Bump to 4.7.0

Currently translated at 100.0% (4624 of 4624 strings)

Translation: pretix/pretix
Translate-URL: https://translate.pretix.eu/projects/pretix/pretix/de_Informal/

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.github/dependabot.yml

@@ -0,0 +1,15 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://help.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "pip"
+    directory: "/src"
+    schedule:
+      interval: "daily"
+  - package-ecosystem: "npm"
+    directory: "/src/pretix/static/npm_dir"
+    schedule:
+      interval: "monthly"

.github/workflows/tests.yml

@@ -18,17 +18,17 @@ jobs:
     name: Tests
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8]
+        python-version: ["3.7", "3.8", "3.9"]
         database: [sqlite, postgres, mysql]
         exclude:
           - database: mysql
-            python-version: 3.7
-          - database: sqlite
-            python-version: 3.7
+            python-version: "3.8"
           - database: mysql
-            python-version: 3.6
+            python-version: "3.9"
           - database: sqlite
-            python-version: 3.6
+            python-version: "3.7"
+          - database: sqlite
+            python-version: "3.8"
     steps:
       - uses: actions/checkout@v2
       - uses: getong/mariadb-action@v1.1
@@ -55,7 +55,7 @@ jobs:
           restore-keys: |
             ${{ runner.os }}-pip-
       - name: Install system dependencies
-        run: sudo apt update && sudo apt install gettext mysql-client
+        run: sudo apt update && sudo apt install gettext mariadb-client
       - name: Install Python dependencies
         run: pip3 install -e ".[dev]" mysqlclient psycopg2-binary
         working-directory: ./src

doc/admin/config.rst

@@ -220,12 +220,30 @@ Example::
 ``user``, ``password``
     The SMTP user data to use for the connection. Empty by default.
 
+``tls``, ``ssl``
+    Use STARTTLS or SSL for the SMTP connection. Off by default.
+
 ``from``
     The email address to set as ``From`` header in outgoing emails by the system.
     Default: ``pretix@localhost``
 
-``tls``, ``ssl``
-    Use STARTTLS or SSL for the SMTP connection. Off by default.
+``from_notifications``
+    The email address to set as ``From`` header in admin notification emails by the system.
+    Defaults to the value of ``from``.
+
+``from_organizers``
+    The email address to set as ``From`` header in outgoing emails by the system sent on behalf of organizers.
+    Defaults to the value of ``from``.
+
+``custom_sender_verification_required``
+    If this is on (the default), organizers need to verify email addresses they want to use as senders in their event.
+
+``custom_sender_spf_string``
+    If this is set to a valid SPF string, pretix will show a warning if organizers use a sender address from a domain
+    that does not include this value.
+
+``custom_smtp_allow_private_networks``
+    If this is off (the default), custom SMTP servers cannot be private network addresses.
 
 ``admins``
     Comma-separated list of email addresses that should receive a report about every error code 500 thrown by pretix.
@@ -282,7 +300,7 @@ You can use an existing memcached server as pretix's caching backend::
 ``location``
     The location of memcached, either a host:port combination or a socket file.
 
-If no memcached is configured, pretix will use Django's built-in local-memory caching method.
+If no memcached is configured, pretix will use redis for caching. If neither is configured, pretix will not use any caching.
 
 .. note:: If you use memcached and you deploy pretix across multiple servers, you should use *one*
           shared memcached instance, not multiple ones, because cache invalidations would not be
@@ -445,8 +463,10 @@ You can configure the maximum file size for uploading various files::
     max_size_image = 12
     ; Max upload size for favicons in MiB, defaults to 1 MiB
     max_size_favicon = 2
-    ; Max upload size for email attachments in MiB, defaults to 10 MiB
+    ; Max upload size for email attachments of manually sent emails in MiB, defaults to 10 MiB
     max_size_email_attachment = 15
+    ; Max upload size for email attachments of automatically sent emails in MiB, defaults to 1 MiB
+    max_size_email_auto_attachment = 2
     ; Max upload size for other files in MiB, defaults to 10 MiB
     ; This includes all file upload type order questions
     max_size_other = 100

doc/admin/errors.rst

@@ -0,0 +1,40 @@
+.. _`admin-errors`:
+
+Dealing with errors
+===================
+
+If you encounter an error in pretix, please follow the following steps to debug it:
+
+* If the error message is shown on a **white page** and the last line of the error includes "nginx", the error is not with pretix
+  directly but with your nginx webserver. This might mean that pretix is not running, but it could also be something else.
+  Please first check your nginx error log. The default location is ``/var/log/nginx/error.log``.
+
+  * If it turns out pretix is not running, check the output of ``docker logs pretix`` for a docker installation and
+    ``journalctl -u pretix-web.service`` for a manual installation.
+
+* If the error message is an "**Internal Server Error**" in purple pretix design, please check pretix' log file which by default is at
+  ``/var/pretix-data/logs/pretix.log`` if you installed with docker and ``/var/pretix/data/logs/pretix.log`` otherwise. If you don't
+  know how to interpret it, open a discussion on GitHub with the relevant parts of the log file.
+
+  * If the error message includes ``/usr/bin/env: ‘node’: No such file or directory``, you forgot to install ``node.js``
+
+  * If the error message includes ``OfflineGenerationError``, you might have forgot to run the ``rebuild`` step after a pretix update
+    or plugin installation.
+
+  * If the error message mentions your database server or redis server, make sure these are running and accessible.
+
+* If pretix loads fine but certain actions (creating carts, orders, or exports, downloading tickets, sending emails) **take forever**,
+  ``pretix-worker`` is not running. Check the output of ``docker logs pretix`` for a docker installation and
+  ``journalctl -u pretix-worker.service`` for a manual installation.
+
+* If the page loads but all **styles are missing**, you probably forgot to update your nginx configuration file after an upgrade of your
+  operating system's python version.
+
+
+If you are unable to debug the issue any further, please open a **discussion** on GitHub in our `Q&A Forum`_. Do **not** open an issue
+right away, since most things turn out not to be a bug in pretix but a mistake in your server configuration. Make sure to include
+relevant log excerpts in your question.
+
+If you're a pretix Enterprise customer, you can also reach out to support@pretix.eu with your issue right away.
+
+.. _Q&A Forum: https://github.com/pretix/pretix/discussions/categories/q-a

doc/admin/index.rst

@@ -9,7 +9,9 @@ This documentation is for everyone who wants to install pretix on a server.
    :maxdepth: 2
 
    installation/index
+   updates
    config
    maintainance
    scaling
+   errors
    indexes

doc/admin/indexes.rst

@@ -50,7 +50,7 @@ Here is the currently recommended set of commands::
     CREATE INDEX CONCURRENTLY pretix_addidx_orderpos_name
         ON pretixbase_orderposition
         USING gin (upper("attendee_name_cached") gin_trgm_ops);
-    CREATE INDEX CONCURRENTLY pretix_addidx_orderpos_scret
+    CREATE INDEX CONCURRENTLY pretix_addidx_orderpos_secret
         ON pretixbase_orderposition
         USING gin (upper("secret") gin_trgm_ops);
     CREATE INDEX CONCURRENTLY pretix_addidx_orderpos_email

doc/admin/installation/docker_smallscale.rst

@@ -36,9 +36,6 @@ Linux and firewalls, we recommend that you start with `ufw`_.
           SSL certificates can be obtained for free these days. We also *do not* provide support for HTTP-only
           installations except for evaluation purposes.
 
-.. warning:: We recommend **PostgreSQL**. If you go for MySQL, make sure you run **MySQL 5.7 or newer** or
-             **MariaDB 10.2.7 or newer**.
-
 .. warning:: By default, using `ufw` in conjunction will not have any effect. Please make sure to either bind the exposed
              ports of your docker container explicitly to 127.0.0.1 or configure docker to respect any set up firewall
              rules.
@@ -61,6 +58,9 @@ directory writable to the user that runs pretix inside the docker container::
 Database
 --------
 
+.. warning:: **Please use PostgreSQL for all new installations**. If you need to go for MySQL, make sure you run
+             **MySQL 5.7 or newer** or **MariaDB 10.2.7 or newer**.
+
 Next, we need a database and a database user. We can create these with any kind of database managing tool or directly on
 our database's shell. Please make sure that UTF8 is used as encoding for the best compatibility. You can check this with
 the following command::
@@ -91,6 +91,8 @@ When using MySQL, make sure you set the character set of the database to ``utf8m
 
     mysql > CREATE DATABASE pretix DEFAULT CHARACTER SET utf8mb4 DEFAULT COLLATE utf8mb4_unicode_ci;
 
+You will also need to make sure that ``sql_mode`` in your ``my.cnf`` file does **not** include ``ONLY_FULL_GROUP_BY``.
+
 Redis
 -----
 
@@ -106,6 +108,18 @@ Now restart redis-server::
 
     # systemctl restart redis-server
 
+In this setup, systemd will delete ``/var/run/redis`` on every redis restart, which will cause issues with pretix. To
+prevent this, you can execute::
+
+   # systemctl edit redis-server
+
+And insert the following::
+
+    [Service]
+    # Keep the directory around so that pretix.service in docker does not need to be
+    # restarted when redis is restarted.
+    RuntimeDirectoryPreserve=yes
+
 .. warning:: Setting the socket permissions to 777 is a possible security problem. If you have untrusted users on your
              system or have high security requirements, please don't do this and let redis listen to a TCP socket
              instead. We recommend the socket approach because the TCP socket in combination with docker's networking
@@ -256,6 +270,8 @@ create an event and start selling tickets!
 
 You should probably read :ref:`maintainance` next.
 
+.. _`docker_updates`:
+
 Updates
 -------
 
@@ -271,6 +287,8 @@ Restarting the service can take a few seconds, especially if the update requires
 Replace ``stable`` above with a specific version number like ``1.0`` or with ``latest`` for the development
 version, if you want to.
 
+Make sure to also read :ref:`update_notes` and the release notes of the version you are updating to.
+
 .. _`docker_plugininstall`:
 
 Install a plugin

doc/admin/installation/manual_smallscale.rst

@@ -34,9 +34,6 @@ Linux and firewalls, we recommend that you start with `ufw`_.
           SSL certificates can be obtained for free these days. We also *do not* provide support for HTTP-only
           installations except for evaluation purposes.
 
-.. warning:: We recommend **PostgreSQL**. If you go for MySQL, make sure you run **MySQL 5.7 or newer** or
-             **MariaDB 10.2.7 or newer**.
-
 Unix user
 ---------
 
@@ -50,6 +47,9 @@ In this guide, all code lines prepended with a ``#`` symbol are commands that yo
 Database
 --------
 
+.. warning:: **Please use PostgreSQL for all new installations**. If you need to go for MySQL, make sure you run
+             **MySQL 5.7 or newer** or **MariaDB 10.2.7 or newer**.
+
 Having the database server installed, we still need a database and a database user. We can create these with any kind
 of database managing tool or directly on our database's shell. Please make sure that UTF8 is used as encoding for the
 best compatibility. You can check this with the following command::
@@ -65,6 +65,8 @@ When using MySQL, make sure you set the character set of the database to ``utf8m
 
     mysql > CREATE DATABASE pretix DEFAULT CHARACTER SET utf8mb4 DEFAULT COLLATE utf8mb4_unicode_ci;
 
+You will also need to make sure that ``sql_mode`` in your ``my.cnf`` file does **not** include ``ONLY_FULL_GROUP_BY``.
+
 Package dependencies
 --------------------
 
@@ -142,7 +144,7 @@ If you're running MySQL, also install the client library::
 
     (venv)$ pip3 install mysqlclient
 
-Note that you need Python 3.6 or newer. You can find out your Python version using ``python -V``.
+Note that you need Python 3.7 or newer. You can find out your Python version using ``python -V``.
 
 We also need to create a data directory::
 
@@ -259,14 +261,14 @@ The following snippet is an example on how to configure a nginx proxy for pretix
         }
 
         location /static/ {
-            alias /var/pretix/venv/lib/python3.7/site-packages/pretix/static.dist/;
+            alias /var/pretix/venv/lib/python3.10/site-packages/pretix/static.dist/;
             access_log off;
             expires 365d;
             add_header Cache-Control "public";
         }
     }
 
-.. note:: Remember to replace the ``python3.7`` in the ``/static/`` path in the config 
+.. note:: Remember to replace the ``python3.10`` in the ``/static/`` path in the config
           above with your python version.
 
 We recommend reading about setting `strong encryption settings`_ for your web server.
@@ -280,6 +282,8 @@ create an event and start selling tickets!
 
 You should probably read :ref:`maintainance` next.
 
+.. _`manual_updates`:
+
 Updates
 -------
 
@@ -294,6 +298,7 @@ To upgrade to a new pretix release, pull the latest code changes and run the fol
     (venv)$ python -m pretix updatestyles
     # systemctl restart pretix-web pretix-worker
 
+Make sure to also read :ref:`update_notes` and the release notes of the version you are updating to.
 
 .. _`manual_plugininstall`:
 

doc/admin/maintainance.rst

@@ -9,6 +9,8 @@ If you host your own pretix instance, you also need to care about the availabili
 of your service and the safety of your data yourself. This page gives you some
 information that you might need to do so properly.
 
+.. _`backups`:
+
 Backups
 -------
 

doc/admin/updates.rst

@@ -0,0 +1,51 @@
+.. _`update_notes`:
+
+Update notes
+============
+
+pretix receives regular feature and bugfix updates and we highly encourage you to always update to
+the latest version for maximum quality and security. Updates are announces on our `blog`_. There are
+usually 10 feature updates in a year, so you can expect a new release almost every month.
+
+Pure bugfix releases are only issued in case of very critical bugs or security vulnerabilities. In these
+case, we'll publish bugfix releases for the last three stable release branches.
+
+Compatibility to plugins and in very rare cases API clients may break. For in-depth details on the
+API changes of every version, please refer to the release notes published on our blog.
+
+Upgrade steps
+-------------
+
+For the actual upgrade, you can usually just follow the steps from the installation guide for :ref:`manual installations <manual_updates>`
+or :ref:`docker installations <docker_updates>` respectively.
+Generally, it is always strongly recommended to perform a :ref:`backup <backups>` first.
+It is possible to skip versions during updates, although we recommend not skipping over major version numbers
+(i.e. if you want to go from 2.4 to 4.4, first upgrade to 3.0, then upgrade to 4.0, then to 4.4).
+
+In addition to these standard update steps, the following list issues steps that should be taken when you upgrade
+to specific versions for pretix. If you're skipping versions, please read the instructions for every version in
+between as well.
+
+Upgrade to 3.17.0 or newer
+""""""""""""""""""""""""""
+
+pretix 3.17 introduces a dependency on ``nodejs``, so you should install it on your system::
+
+    # apt install nodejs npm
+
+Upgrade to 4.4.0 or newer
+"""""""""""""""""""""""""
+
+pretix 4.4 introduces a new data structure to store historical financial data. If you already have existing
+data in your database, you will need to back-fill this data or you might get incorrect reports! This is not
+done automatically as part of the usual update steps since it can take a while on large databases and you might
+want to do it in parallel while the system is already running again. Please execute the following command::
+
+    (venv)$ python -m pretix create_order_transactions
+
+Or, with a docker installation::
+
+    $ docker exec -it pretix.service pretix create_order_transactions
+
+
+.. _blog: https://pretix.eu/about/en/blog/

doc/api/guides/custom_checkout.rst

@@ -97,7 +97,8 @@ For example, if you want users to be redirected to ``https://example.org/order/r
 either enter ``https://example.org`` or ``https://example.org/order/``.
 
 The user will be redirected back to your page instead of pretix' order confirmation page after the payment,
-**regardless of whether it was successful or not**. Make sure you use our API to check if the payment actually
+**regardless of whether it was successful or not**. We will append an ``error=…`` query parameter with an error
+message, but you should not rely on that and instead make sure you use our API to check if the payment actually
 worked! Your final URL could look like this::
 
     https://test.pretix.eu/democon/3vjrh/order/NSLEZ/ujbrnsjzbq4dzhck/pay/123/?return_url=https%3A%2F%2Fexample.org%2Forder%2Freturn%3Ftx_id%3D1234

doc/api/resources/index.rst

@@ -31,5 +31,6 @@ Resources and endpoints
    webhooks
    seatingplans
    exporters
+   sendmail_rules
    billing_invoices
    billing_var

doc/api/resources/invoices.rst

@@ -58,6 +58,12 @@ lines                                 list of objects            The actual invo
                                                                  created before this field was introduced as well as for
                                                                  all lines not created by a product (e.g. a shipping or
                                                                  cancellation fee).
+├ subevent                            integer                    Event series date ID used to create this line. Note that everything
+                                                                 about the subevent might have changed since the creation
+                                                                 of the invoice. Can be ``null`` for all invoice lines
+                                                                 created before this field was introduced as well as for
+                                                                 all lines not created by a product (e.g. a shipping or
+                                                                 cancellation fee) as well as for all events that are not a series.
 ├ fee_type                            string                     Fee type, e.g. ``shipping``, ``service``, ``payment``,
                                                                  ``cancellation``, ``giftcard``, or ``other. Can be ``null`` for
                                                                  all invoice lines
@@ -78,6 +84,12 @@ lines                                 list of objects            The actual invo
                                                                  an event series not created by a product (e.g. shipping or
                                                                  cancellation fees) as well as whenever the respective (sub)event
                                                                  has no end date set.
+├ event_location                      string                     Location of the (sub)event this line was created for as it
+                                                                 was set during invoice creation. Can be ``null`` for all invoice
+                                                                 lines created before this was introduced as well as for lines in
+                                                                 an event series not created by a product (e.g. shipping or
+                                                                 cancellation fees) as well as whenever the respective (sub)event
+                                                                 has no location set.
 ├ attendee_name                       string                     Attendee name at time of invoice creation. Can be ``null`` if no
                                                                  name was set or if names are configured to not be added to invoices.
 ├ gross_value                         money (string)             Price including taxes
@@ -110,6 +122,14 @@ internal_reference                    string                     Customer's refe
 
    The attributes ``fee_type`` and ``fee_internal_type`` have been added.
 
+.. versionchanged:: 4.1
+
+   The attribute ``lines.event_location`` has been added.
+
+.. versionchanged:: 4.6
+
+   The attribute ``lines.subevent`` has been added.
+
 
 Endpoints
 ---------
@@ -175,10 +195,12 @@ Endpoints
                 "description": "Budget Ticket",
                 "item": 1234,
                 "variation": 245,
+                "subevent": null,
                 "fee_type": null,
                 "fee_internal_type": null,
                 "event_date_from": "2017-12-27T10:00:00Z",
                 "event_date_to": null,
+                "event_location": "Heidelberg",
                 "attendee_name": null,
                 "gross_value": "23.00",
                 "tax_value": "0.00",
@@ -263,10 +285,12 @@ Endpoints
             "description": "Budget Ticket",
             "item": 1234,
             "variation": 245,
+            "subevent": null,
             "fee_type": null,
             "fee_internal_type": null,
             "event_date_from": "2017-12-27T10:00:00Z",
             "event_date_to": null,
+            "event_location": "Heidelberg",
             "attendee_name": null,
             "gross_value": "23.00",
             "tax_value": "0.00",

doc/api/resources/item_variations.rst

@@ -24,7 +24,12 @@ active                                boolean                    If ``false``, t
 description                           multi-lingual string       A public description of the variation. May contain
                                                                  Markdown syntax or can be ``null``.
 position                              integer                    An integer, used for sorting
+require_approval                      boolean                    If ``true``, orders with this variation will need to be
+                                                                 approved by the event organizer before they can be
+                                                                 paid.
 require_membership                    boolean                    If ``true``, booking this variation requires an active membership.
+require_membership_hidden             boolean                    If ``true`` and ``require_membership`` is set, this variation will
+                                                                 be hidden from users without a valid membership.
 require_membership_types              list of integers           Internal IDs of membership types valid if ``require_membership`` is ``true``
 sales_channels                        list of strings            Sales channels this variation is available on, such as
                                                                  ``"web"`` or ``"resellers"``. Defaults to all existing sales channels.
@@ -74,7 +79,9 @@ Endpoints
               "en": "S"
             },
             "active": true,
+            "require_approval": false,
             "require_membership": false,
+            "require_membership_hidden": false,
             "require_membership_types": [],
             "sales_channels": ["web"],
             "available_from": null,
@@ -94,7 +101,9 @@ Endpoints
               "en": "L"
             },
             "active": true,
+            "require_approval": false,
             "require_membership": false,
+            "require_membership_hidden": false,
             "require_membership_types": [],
             "description": {},
             "position": 1,
@@ -143,7 +152,9 @@ Endpoints
         "price": "10.00",
         "original_price": null,
         "active": true,
+        "require_approval": false,
         "require_membership": false,
+        "require_membership_hidden": false,
         "require_membership_types": [],
         "sales_channels": ["web"],
         "available_from": null,
@@ -178,7 +189,9 @@ Endpoints
         "value": {"en": "Student"},
         "default_price": "10.00",
         "active": true,
+        "require_approval": false,
         "require_membership": false,
+        "require_membership_hidden": false,
         "require_membership_types": [],
         "sales_channels": ["web"],
         "available_from": null,
@@ -203,7 +216,9 @@ Endpoints
         "price": "10.00",
         "original_price": null,
         "active": true,
+        "require_approval": false,
         "require_membership": false,
+        "require_membership_hidden": false,
         "require_membership_types": [],
         "sales_channels": ["web"],
         "available_from": null,
@@ -259,7 +274,9 @@ Endpoints
         "price": "10.00",
         "original_price": null,
         "active": false,
+        "require_approval": false,
         "require_membership": false,
+        "require_membership_hidden": false,
         "require_membership_types": [],
         "sales_channels": ["web"],
         "available_from": null,

doc/api/resources/items.rst

@@ -70,6 +70,8 @@ require_approval                      boolean                    If ``true``, or
                                                                  paid.
 require_bundling                      boolean                    If ``true``, this item is only available as part of bundles.
 require_membership                    boolean                    If ``true``, booking this item requires an active membership.
+require_membership_hidden             boolean                    If ``true`` and ``require_membership`` is set, this product will
+                                                                 be hidden from users without a valid membership.
 require_membership_types              list of integers           Internal IDs of membership types valid if ``require_membership`` is ``true``
 grant_membership_type                 integer                    If set to the internal ID of a membership type, purchasing this item will
                                                                  create a membership of the given type.
@@ -105,6 +107,8 @@ variations                            list of objects            A list with one
 ├ active                              boolean                    If ``false``, this variation will not be sold or shown.
 ├ description                         multi-lingual string       A public description of the variation. May contain
 ├ require_membership                  boolean                    If ``true``, booking this variation requires an active membership.
+├ require_membership_hidden           boolean                    If ``true`` and ``require_membership`` is set, this variation will
+                                                                 be hidden from users without a valid membership.
 ├ require_membership_types            list of integers           Internal IDs of membership types valid if ``require_membership`` is ``true``
                                                                  Markdown syntax or can be ``null``.
 ├ sales_channels                      list of strings            Sales channels this variation is available on, such as
@@ -155,6 +159,10 @@ meta_data                             object                     Values set for
    The attributes ``require_membership``, ``require_membership_types``, ``grant_membership_type``, ``grant_membership_duration_like_event``,
     ``grant_membership_duration_days`` and ``grant_membership_duration_months`` have been added.
 
+.. versionchanged:: 4.4
+
+   The attributes ``require_membership_hidden`` attribute has been added.
+
 Notes
 -----
 

doc/api/resources/orders.rst

@@ -128,6 +128,14 @@ last_modified                         datetime                   Last modificati
 
    The ``custom_followup_at`` attribute has been added.
 
+.. versionchanged:: 4.4
+
+   The ``item`` and ``variation`` query parameters have been added.
+
+.. versionchanged:: 4.6
+
+   The ``subevent`` query parameters has been added.
+
 
 .. _order-position-resource:
 
@@ -415,6 +423,8 @@ List of all orders
    :query string code: Only return orders that match the given order code
    :query string status: Only return orders in the given order status (see above)
    :query string search: Only return orders matching a given search query
+   :query integer item: Only return orders with a position that contains this item ID. *Warning:* Result will also include orders if they contain mixed items, and it will even return orders where the item is only contained in a canceled position.
+   :query integer variation: Only return orders with a position that contains this variation ID. *Warning:* Result will also include orders if they contain mixed items and variations, and it will even return orders where the variation is only contained in a canceled position.
    :query boolean testmode: Only return orders with ``testmode`` set to ``true`` or ``false``
    :query boolean require_approval: If set to ``true`` or ``false``, only categories with this value for the field
                                     ``require_approval`` will be returned.
@@ -427,6 +437,7 @@ List of all orders
        recommend using this in combination with ``testmode=false``, since test mode orders can vanish at any time and
        you will not notice it using this method.
    :query datetime created_since: Only return orders that have been created since the given date.
+   :query integer subevent: Only return orders with a position that contains this subevent ID. *Warning:* Result will also include orders if they contain mixed subevents, and it will even return orders where the subevent is only contained in a canceled position.
    :query datetime subevent_after: Only return orders that contain a ticket for a subevent taking place after the given date. This is an exclusive after, and it considers the **end** of the subevent (or its start, if the end is not set).
    :query datetime subevent_before: Only return orders that contain a ticket for a subevent taking place after the given date. This is an exclusive before, and it considers the **start** of the subevent.
    :query string exclude: Exclude a field from the output, e.g. ``fees`` or ``positions.downloads``. Can be used as a performance optimization. Can be passed multiple times.
@@ -828,6 +839,7 @@ Creating orders
    * ``comment`` (optional)
    * ``custom_followup_at`` (optional)
    * ``checkin_attention`` (optional)
+   * ``require_approval`` (optional)
    * ``invoice_address`` (optional)
 
       * ``company``
@@ -887,8 +899,9 @@ Creating orders
 
    * ``force`` (optional). If set to ``true``, quotas will be ignored.
    * ``send_email`` (optional). If set to ``true``, the same emails will be sent as for a regular order, regardless of
-     whether these emails are enabled for certain sales channels. Defaults to
-     ``false``. Used to be ``send_mail`` before pretix 3.14.
+     whether these emails are enabled for certain sales channels. If set to ``null``, behavior will be controlled by pretix'
+     settings based on the sales channels (added in pretix 4.7). Defaults to ``false``.
+     Used to be ``send_mail`` before pretix 3.14.
 
    If you want to use add-on products, you need to set the ``positionid`` fields of all positions manually
    to incrementing integers starting with ``1``. Then, you can reference one of these

doc/api/resources/sendmail_rules.rst

@@ -0,0 +1,281 @@
+Automated email rules
+=====================
+
+Resource description
+--------------------
+
+Automated email rules that specify emails that the system will send automatically at a specific point in time, e.g.
+the day of the event.
+
+.. rst-class:: rest-resource-table
+
+===================================== ========================== =======================================================
+Field                                 Type                       Description
+===================================== ========================== =======================================================
+id                                    integer                    Internal ID of the rule
+enabled                               boolean                    If ``false``, the rule is ignored
+subject                               multi-lingual string       The subject of the email
+template                              multi-lingual string       The body of the email
+all_products                          boolean                    If ``true``, the email is sent to buyers of all products
+limit_products                        list of integers           List of product IDs, if ``all_products`` is not set
+include_pending                       boolean                    If ``true``, the email is sent to pending orders. If ``false``,
+                                                                 only paid orders are considered.
+date_is_absolute                      boolean                    If ``true``, the email is set at a specific point in time.
+send_date                             datetime                   If ``date_is_absolute`` is set: Date and time to send the email.
+send_offset_days                      integer                    If ``date_is_absolute`` is not set, this is the number of days
+                                                                 before/after the email is sent.
+send_offset_time                      time                       If ``date_is_absolute`` is not set, this is the time of day the
+                                                                 email is sent on the day specified by ``send_offset_days``.
+offset_to_event_end                   boolean                    If ``true``, ``send_offset_days`` is relative to the event end
+                                                                 date. Otherwise it is relative to the event start date.
+offset_is_after                       boolean                    If ``true``, ``send_offset_days`` is the number of days **after**
+                                                                 the event start or end date. Otherwise it is the number of days
+                                                                 **before**.
+send_to                               string                     Can be ``"orders"`` if the email should be sent to customers
+                                                                 (one email per order),
+                                                                 ``"attendees"`` if the email should be sent to every attendee,
+                                                                 or ``"both"``.
+                                                                 date. Otherwise it is relative to the event start date.
+===================================== ========================== =======================================================
+
+
+Endpoints
+---------
+
+.. http:get:: /api/v1/organizers/(organizer)/events/(event)/sendmail_rules/
+
+   Returns a list of all rules configured for an event.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      GET /api/v1/organizers/bigevents/events/sampleconf/sendmail_rules/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: application/json
+
+      {
+        "count": 1,
+        "next": null,
+        "previous": null,
+        "results": [
+          {
+            "id": 1,
+            "enabled": true,
+            "subject": {"en": "See you tomorrow!"},
+            "template": {"en": "Don't forget your tickets, download them at {url}"},
+            "all_products": true,
+            "limit_products": [],
+            "include_pending": false,
+            "send_date": null,
+            "send_offset_days": 1,
+            "send_offset_time": "18:00",
+            "date_is_absolute": false,
+            "offset_to_event_end": false,
+            "offset_is_after": false,
+            "send_to": "orders"
+          }
+        ]
+      }
+
+   :query page: The page number in case of a multi-page result set, default is 1
+   :param organizer: The ``slug`` field of a valid organizer
+   :param event: The ``slug`` field of the event to fetch
+   :statuscode 200: no error
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer does not exist **or** you have no permission to view it.
+
+.. http:get:: /api/v1/organizers/(organizer)/events/(event)/sendmail_rules/(id)/
+
+   Returns information on one rule, identified by its ID.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      GET /api/v1/organizers/bigevents/events/sampleconf/sendmail_rules/1/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: application/json
+
+      {
+        "id": 1,
+        "enabled": true,
+        "subject": {"en": "See you tomorrow!"},
+        "template": {"en": "Don't forget your tickets, download them at {url}"},
+        "all_products": true,
+        "limit_products": [],
+        "include_pending": false,
+        "send_date": null,
+        "send_offset_days": 1,
+        "send_offset_time": "18:00",
+        "date_is_absolute": false,
+        "offset_to_event_end": false,
+        "offset_is_after": false,
+        "send_to": "orders"
+      }
+
+   :param organizer: The ``slug`` field of the organizer to fetch
+   :param event: The ``slug`` field of the event to fetch
+   :param id: The ``id`` field of the rule to fetch
+   :statuscode 200: no error
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event/rule does not exist **or** you have no permission to view it.
+
+.. http:post:: /api/v1/organizers/(organizer)/events/(event)/sendmail_rules/
+
+   Create a new rule.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      POST /api/v1/organizers/bigevents/events/sampleconf/sendmail_rules/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+      Content-Type: application/json
+      Content-Length: 166
+
+      {
+        "enabled": true,
+        "subject": {"en": "See you tomorrow!"},
+        "template": {"en": "Don't forget your tickets, download them at {url}"},
+        "all_products": true,
+        "limit_products": [],
+        "include_pending": false,
+        "send_date": null,
+        "send_offset_days": 1,
+        "send_offset_time": "18:00",
+        "date_is_absolute": false,
+        "offset_to_event_end": false,
+        "offset_is_after": false,
+        "send_to": "orders"
+      }
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 201 Created
+      Vary: Accept
+      Content-Type: application/json
+
+      {
+        "id": 1,
+        "enabled": true,
+        "subject": {"en": "See you tomorrow!"},
+        "template": {"en": "Don't forget your tickets, download them at {url}"},
+        "all_products": true,
+        "limit_products": [],
+        "include_pending": false,
+        "send_date": null,
+        "send_offset_days": 1,
+        "send_offset_time": "18:00",
+        "date_is_absolute": false,
+        "offset_to_event_end": false,
+        "offset_is_after": false,
+        "send_to": "orders"
+      }
+
+   :param organizer: The ``slug`` field of the organizer to create a rule for
+   :param event: The ``slug`` field of the event to create a rule for
+   :statuscode 201: no error
+   :statuscode 400: The rule could not be created due to invalid submitted data.
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event does not exist **or** you have no permission to create rules.
+
+
+.. http:patch:: /api/v1/organizers/(organizer)/events/(event)/sendmail_rules/(id)/
+
+   Update a rule. You can also use ``PUT`` instead of ``PATCH``. With ``PUT``, you have to provide all fields of
+   the resource, other fields will be reset to default. With ``PATCH``, you only need to provide the fields that you
+   want to change.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      PATCH /api/v1/organizers/bigevents/events/sampleconf/sendmail_rules/1/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+      Content-Type: application/json
+      Content-Length: 34
+
+      {
+        "enabled": false,
+      }
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: text/javascript
+
+      {
+        "id": 1,
+        "enabled": false,
+        "subject": {"en": "See you tomorrow!"},
+        "template": {"en": "Don't forget your tickets, download them at {url}"},
+        "all_products": true,
+        "limit_products": [],
+        "include_pending": false,
+        "send_date": null,
+        "send_offset_days": 1,
+        "send_offset_time": "18:00",
+        "date_is_absolute": false,
+        "offset_to_event_end": false,
+        "offset_is_after": false,
+        "send_to": "orders"
+      }
+
+   :param organizer: The ``slug`` field of the organizer to modify
+   :param event: The ``slug`` field of the event to modify
+   :param id: The ``id`` field of the rule to modify
+   :statuscode 200: no error
+   :statuscode 400: The rule could not be modified due to invalid submitted data.
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event/rule does not exist **or** you have no permission to change it.
+
+
+.. http:delete:: /api/v1/organizers/(organizer)/events/(event)/sendmail_rules/(id)/
+
+   Delete a rule.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      DELETE /api/v1/organizers/bigevents/events/sampleconf/sendmail_rules/1/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 204 No Content
+      Vary: Accept
+
+   :param organizer: The ``slug`` field of the organizer to modify
+   :param event: The ``slug`` field of the event to modify
+   :param id: The ``id`` field of the rule to delete
+   :statuscode 204: no error
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event/rule does not exist **or** you have no permission to change it **or** this rule cannot be deleted since it is currently in use.

doc/api/resources/taxrules.rst

@@ -16,15 +16,22 @@ Field                                 Type                       Description
 ===================================== ========================== =======================================================
 id                                    integer                    Internal ID of the tax rule
 name                                  multi-lingual string       The tax rules' name
+internal_name                         string                     An optional name that is only used in the backend
 rate                                  decimal (string)           Tax rate in percent
 price_includes_tax                    boolean                    If ``true`` (default), tax is assumed to be included in
                                                                  the specified product price
 eu_reverse_charge                     boolean                    If ``true``, EU reverse charge rules are applied
 home_country                          string                     Merchant country (required for reverse charge), can be
                                                                  ``null`` or empty string
+keep_gross_if_rate_changes            boolean                    If ``true``, changes of the tax rate based on custom
+                                                                 rules keep the gross price constant (default is ``false``)
 ===================================== ========================== =======================================================
 
 
+.. versionchanged:: 4.6
+
+    The ``internal_name`` and ``keep_gross_if_rate_changes`` attributes have been added.
+
 Endpoints
 ---------
 
@@ -56,9 +63,11 @@ Endpoints
           {
             "id": 1,
             "name": {"en": "VAT"},
+            "internal_name": "VAT",
             "rate": "19.00",
             "price_includes_tax": true,
             "eu_reverse_charge": false,
+            "keep_gross_if_rate_changes": false,
             "home_country": "DE"
           }
         ]
@@ -94,9 +103,11 @@ Endpoints
       {
         "id": 1,
         "name": {"en": "VAT"},
+        "internal_name": "VAT",
         "rate": "19.00",
         "price_includes_tax": true,
         "eu_reverse_charge": false,
+        "keep_gross_if_rate_changes": false,
         "home_country": "DE"
       }
 
@@ -140,9 +151,11 @@ Endpoints
       {
         "id": 1,
         "name": {"en": "VAT"},
+        "internal_name": "VAT",
         "rate": "19.00",
         "price_includes_tax": true,
         "eu_reverse_charge": false,
+        "keep_gross_if_rate_changes": false,
         "home_country": "DE"
       }
 
@@ -185,9 +198,11 @@ Endpoints
       {
         "id": 1,
         "name": {"en": "VAT"},
+        "internal_name": "VAT",
         "rate": "20.00",
         "price_includes_tax": true,
         "eu_reverse_charge": false,
+        "keep_gross_if_rate_changes": false,
         "home_country": "DE"
       }
 

doc/development/algorithms/index.rst

@@ -2,7 +2,7 @@ Algorithms
 ==========
 
 The business logic inside pretix is full of complex algorithms making decisions based on all the hundreds of settings
-and input parameters available. Some of them are documented here as graphs, either because fully understanding them is very
+and input parameters available. Some of them are documented here as graphs, either because fully understanding them is very important
 when working on features close to them, or because they also need to be re-implemented by client-side components like our
 ticket scanning apps and we want to ensure the implementations are as similar as possible to avoid confusion.
 

doc/development/api/auth.rst

@@ -20,20 +20,31 @@ Basically, three pre-defined flows are supported:
 * Authentication mechanisms that rely on **redirection**, e.g. to an OAuth provider. These can be implemented by
   supplying a ``authentication_url`` method and implementing a custom return view.
 
-Authentication backends are *not* collected through a signal. Instead, they must explicitly be set through the
-``auth_backends`` directive in the ``pretix.cfg`` :ref:`configuration file <config>`.
+For security reasons, authentication backends are *not* automatically discovered through a signal. Instead, they must
+explicitly be set through the ``auth_backends`` directive in the ``pretix.cfg`` :ref:`configuration file <config>`.
 
-In each of these methods (``form_authenticate``, ``request_authenticate`` or your custom view) you are supposed to
-either get an existing :py:class:`pretix.base.models.User` object from the database or create a new one. There are a
-few rules you need to follow:
+In each of these methods (``form_authenticate``, ``request_authenticate``, or your custom view) you are supposed to
+use ``User.objects.get_or_create_for_backend`` to get a :py:class:`pretix.base.models.User` object from the database
+or create a new one.
 
-* You **MUST** only return users with the ``auth_backend`` attribute set to the ``identifier`` value of your backend.
+There are a few rules you need to follow:
 
-* You **MUST** create new users with the ``auth_backend`` attribute set to the ``identifier`` value of your backend.
+* You **MUST** have some kind of identifier for a user that is globally unique and **SHOULD** never change, even if the
+  user's name or email address changes. This could e.g. be the ID of the user in an external database. The identifier
+  must not be longer than 190 characters. If you worry your backend might generated longer identifiers, consider
+  using a hash function to trim them to a constant length.
+
+* You **SHOULD** not allow users created by other authentication backends to log in through your code, and you **MUST**
+  only create, modify or return users with ``auth_backend`` set to your backend.
 
 * Every user object **MUST** have an email address. Email addresses are globally unique. If the email address is
   already registered to a user who signs in through a different backend, you **SHOULD** refuse the login.
 
+``User.objects.get_or_create_for_backend`` will follow these rules for you automatically. It works like this:
+
+.. autoclass:: pretix.base.models.auth.UserManager
+   :members: get_or_create_for_backend
+
 The backend interface
 ---------------------
 
@@ -59,6 +70,7 @@ The backend interface
 
    .. automethod:: authentication_url
 
+
 Logging users in
 ----------------
 
@@ -68,3 +80,45 @@ recommend that you use the following utility method to correctly set session val
 authentication (if activated):
 
 .. autofunction:: pretix.control.views.auth.process_login
+
+A custom view that is called after a redirect from an external identity provider could look like this::
+
+   from django.contrib import messages
+   from django.shortcuts import redirect
+   from django.urls import reverse
+
+   from pretix.base.models import User
+   from pretix.base.models.auth import EmailAddressTakenError
+   from pretix.control.views.auth import process_login
+
+
+   def return_view(request):
+       # Verify validity of login with the external provider's API
+       api_response = my_verify_login_function(
+           code=request.GET.get('code')
+       )
+
+       try:
+           u = User.objects.get_or_create_for_backend(
+               'my_backend_name',
+               api_response['userid'],
+               api_response['email'],
+               set_always={
+                   'fullname': '{} {}'.format(
+                       api_response.get('given_name', ''),
+                       api_response.get('family_name', ''),
+                   ),
+               },
+               set_on_creation={
+                   'locale': api_response.get('locale').lower()[:2],
+                   'timezone': api_response.get('zoneinfo', 'UTC'),
+               }
+           )
+       except EmailAddressTakenError:
+           messages.error(
+               request, _('We cannot create your user account as a user account in this system '
+                          'already exists with the same email address.')
+           )
+           return redirect(reverse('control:auth.login'))
+       else:
+           return process_login(request, u, keep_logged_in=False)

doc/development/api/cookieconsent.rst

@@ -0,0 +1,119 @@
+.. highlight:: python
+   :linenothreshold: 5
+
+.. _`cookieconsent`:
+
+Handling cookie consent
+=======================
+
+pretix includes an optional feature to handle cookie consent explicitly to comply with EU regulations.
+If your plugin sets non-essential cookies or includes a third-party service that does so, you should
+integrate with this feature.
+
+Server-side integration
+-----------------------
+
+First, you need to declare that you are using non-essential cookies by responding to the following
+signal:
+
+.. automodule:: pretix.presale.signals
+   :members: register_cookie_providers
+
+You are expected to return a list of ``CookieProvider`` objects instantiated from the following class:
+
+.. class:: pretix.presale.cookies.CookieProvider
+
+   .. py:attribute:: CookieProvider.identifier
+
+      A short and unique identifier used to distinguish this cookie provider form others (required).
+
+   .. py:attribute:: CookieProvider.provider_name
+
+      A human-readable name of the entity of feature responsible for setting the cookie (required).
+
+   .. py:attribute:: CookieProvider.usage_classes
+
+      A list of enum values from the ``pretix.presale.cookies.UsageClass`` enumeration class, such as
+      ``UsageClass.ANALYTICS``, ``UsageClass.MARKETING``, or ``UsageClass.SOCIAL`` (required).
+
+   .. py:attribute:: CookieProvider.privacy_url
+
+      A link to a privacy policy (optional).
+
+Here is an example of such a receiver:
+
+.. code-block:: python
+
+   @receiver(register_cookie_providers)
+   def recv_cookie_providers(sender, request, **kwargs):
+       return [
+           CookieProvider(
+               identifier='google_analytics',
+               provider_name='Google Analytics',
+               usage_classes=[UsageClass.ANALYTICS],
+           )
+       ]
+
+JavaScript-side integration
+---------------------------
+
+The server-side integration only causes the cookie provider to show up in the cookie dialog. You still
+need to care about actually enforcing the consent state.
+
+You can access the consent state through the ``window.pretix.cookie_consent`` variable. Whenever the
+value changes, a ``pretix:cookie-consent:change`` event is fired on the ``document`` object.
+
+The variable will generally have one of the following states:
+
+.. rst-class:: rest-resource-table
+
+================================================================ =====================================================
+State                                                            Interpretation
+================================================================ =====================================================
+``pretix === undefined || pretix.cookie_consent === undefined``  Your JavaScript has loaded before the cookie consent
+                                                                 script. Wait for the event to be fired, then try again,
+                                                                 do not yet set a cookie.
+``pretix.cookie_consent === null``                               The cookie consent mechanism has not been enabled. This
+                                                                 usually means that you can set cookies however you like.
+``pretix.cookie_consent[identifier] === undefined``              The cookie consent mechanism is loaded, but has no data
+                                                                 on your cookie yet, wait for the event to be fired, do not
+                                                                 yet set a cookie.
+``pretix.cookie_consent[identifier] === true``                   The user has consented to your cookie.
+``pretix.cookie_consent[identifier] === false``                  The user has actively rejected your cookie.
+================================================================ =====================================================
+
+If you are integrating e.g. a tracking provider with native cookie consent support such
+as Facebook's Pixel, you can integrate it like this:
+
+.. code-block:: javascript
+
+     var consent = (window.pretix || {}).cookie_consent;
+     if (consent !== null && !(consent || {}).facebook) {
+         fbq('consent', 'revoke');
+     }
+     fbq('init', ...);
+     document.addEventListener('pretix:cookie-consent:change', function (e) {
+         fbq('consent', (e.detail || {}).facebook ? 'grant' : 'revoke');
+     })
+
+If you have a JavaScript function that you only want to load if consent for a specific ``identifier``
+is given, you can wrap it like this:
+
+.. code-block:: javascript
+
+     var consent_identifier = "youridentifier";
+     var consent = (window.pretix || {}).cookie_consent;
+     if (consent === null || (consent || {})[consent_identifier] === true) {
+         // Cookie consent tool is either disabled or consent is given
+         addScriptElement(src);
+         return;
+     }
+
+     // Either cookie consent tool has not loaded yet or consent is not given
+     document.addEventListener('pretix:cookie-consent:change', function onChange(e) {
+         var consent = e.detail || {};
+         if (consent === null || consent[consent_identifier] === true) {
+             addScriptElement(src);
+             document.removeEventListener('pretix:cookie-consent:change', onChange);
+         }
+     })

doc/development/api/index.rst

@@ -17,6 +17,7 @@ Contents:
    shredder
    import
    customview
+   cookieconsent
    auth
    general
    quality

doc/development/api/payment.rst

@@ -62,6 +62,8 @@ The provider class
 
    .. autoattribute:: public_name
 
+   .. autoattribute:: confirm_button_name
+
    .. autoattribute:: is_enabled
 
    .. autoattribute:: priority

doc/development/api/plugins.rst

@@ -92,6 +92,7 @@ those will be displayed but not block the plugin execution.
 
 The ``AppConfig`` class may implement a method ``is_available(event)`` that checks if a plugin
 is available for a specific event. If not, it will not be shown in the plugin list of that event.
+You should not define ``is_available`` and ``restricted`` on the same plugin.
 
 Plugin registration
 -------------------

doc/development/contribution/style.rst

@@ -1,6 +1,11 @@
+.. spelling:: Rebase rebasing
+
 Coding style and quality
 ========================
 
+Code
+----
+
 * Basically, we want all python code to follow the `PEP 8`_ standard. There are a few exceptions where
   we see things differently or just aren't that strict. The ``setup.cfg`` file in the project's source
   folder contains definitions that allow `flake8`_ to check for violations automatically. See :ref:`checksandtests`
@@ -20,8 +25,62 @@ Coding style and quality
   test suite are in the style of Python's unit test module. If you extend those files, you might continue in this style,
   but please use ``pytest`` style for any new test files.
 
-* Please keep the first line of your commit messages short. When referencing an issue, please phrase it like
-  ``Fix #123 -- Problems with order creation`` or ``Refs #123 -- Fix this part of that bug``.
+Commits and Pull Requests
+-------------------------
+
+
+
+Most commits should start as pull requests, therefore this applies to the titles of pull requests as well since
+the pull request title will become the commit message on merge. We prefer merging with GitHub's "Squash and merge"
+feature if the PR contains multiple commits that do not carry value to keep. If there is value in keeping the
+individual commits, we use "Rebase and merge" instead. Merge commits should be avoided.
+
+* The commit message should start with a single subject line and can optionally be followed by a commit message body.
+
+  * The subject line should be the shortest possible representation of what the commit changes. Someone who reviewed
+    the commit should able to immediately remember the commit in a couple of weeks based on the subject line and tell
+    it apart from other commits.
+
+  * If there's additional useful information that we should keep, such as reasoning behind the commit, you can
+    add a longer body, separated from the first line by a blank line.
+
+  * The body should explain **what** you changed and more importantly **why** you changed it. There's no need to iterate
+    **how** you changed something.
+
+* The subject line should be capitalized ("Add new feature" instead of "add new feature") and should not end with a period
+  ("Add new feature" instead of "Add new feature.")
+
+* The subject line should be written in imperative mood, as if you were giving a command what the computer should do if the
+  commit is applied. This is how generated commit messages by git itself are already written ("Merge branch …", "Revert …")
+  and makes for short and consistent messages.
+
+  * Good: "Fix typo in template"
+  * Good: "Add Chinese translation"
+  * Good: "Remove deprecated method"
+  * Good: "Bump version to 4.4.0"
+  * Bad: "Fixed bug with …"
+  * Bad: "Fixes bug with …"
+  * Bad: "Fixing bug …"
+
+* If all changes in your commit are in context of a single feature or e.g. a bundled plugin, it makes sense to prefix the
+  subject line with the name of that feature. Examples:
+
+  * "API: Add support for PATCH on customers"
+  * "Docs: Add chapter on alpaca feeding"
+  * "Stripe: Fix duplicate payments"
+  * "Order change form: Fix incorrect validation"
+
+* If your commit references a GitHub issue that is fully resolved by your commit, start your subject line with the issue
+  ID in the form of "Fix #1234 -- Crash in order list". In this case, you can omit the verb "Fix" at the beginning of the
+  second part of the message to avoid repetition of the word "fix". If your commit only partially resolves the issue, use
+  "Refs #1234 -- Crash in order list" instead.
+
+* Applies to pretix employees only: If your commit references a sentry issue, please put it in parentheses at the end
+  of the subject line or inside the body ("Fix crash in order list (PRETIXEU-ABC)"). If your commit references a support
+  ticket, please put it in parentheses at the end of the subject line with a "Z#" prefix ("Fix crash in order list (Z#12345)").
+
+* If your PR was open for a while and might cause conflicts on merge, please prefer rebasing it (``git rebase -i master``)
+  over merging ``master`` into your branch unless it is prohibitively complicated.
 
 
 .. _PEP 8: https://legacy.python.org/dev/peps/pep-0008/

doc/development/implementation/models.rst

@@ -92,6 +92,9 @@ Carts and Orders
 .. autoclass:: pretix.base.models.OrderRefund
    :members:
 
+.. autoclass:: pretix.base.models.Transaction
+   :members:
+
 .. autoclass:: pretix.base.models.CartPosition
    :members:
 

doc/development/setup.rst

@@ -26,7 +26,7 @@ Your should install the following on your system:
 * ``libssl`` (Debian package: ``libssl-dev``)
 * ``libxml2`` (Debian package ``libxml2-dev``)
 * ``libxslt`` (Debian package ``libxslt1-dev``)
-* ``libenchant1c2a`` (Debian package ``libenchant1c2a``)
+* ``libenchant-2-2`` (Debian package ``libenchant-2-2``)
 * ``msgfmt`` (Debian package ``gettext``)
 * ``git``
 
@@ -51,7 +51,12 @@ the dependencies might fail::
 
 Working with the code
 ---------------------
-The first thing you need are all the main application's dependencies::
+If you do not have a recent installation of ``nodejs``, install it now::
+
+    curl -sL https://deb.nodesource.com/setup_17.x | sudo -E bash -
+    sudo apt install nodejs
+
+To make sure it is on your path variable, close and reopen your terminal. Now, install the Python-level dependencies of pretix::
 
     cd src/
     pip3 install -e ".[dev]"

doc/plugins/digital.rst

@@ -61,7 +61,7 @@ Variable                            Description
 ``attendee_city``                   City of the ticket holder's address (or empty)
 ``attendee_country``                Country code of the ticket holder's address (or empty)
 ``attendee_state``                  State of the ticket holder's address (or empty)
-``answer[XYZ]``                     Answer to the custom question with identifier ``XYZ``
+``answers[XYZ]``                    Answer to the custom question with identifier ``XYZ``
 ``invoice_name``                    Full name of the invoice address (or empty)
 ``invoice_name_*``                  Name parts of the invoice address, depending on configuration, e.g. ``invoice_name_given_name`` or ``invoice_name_family_name``
 ``invoice_company``                 Company of the invoice address (or empty)

doc/plugins/imported_secrets.rst

@@ -0,0 +1,301 @@
+Secrets Import
+==============
+
+Usually, pretix generates ticket secrets (i.e. the QR code used for scanning) itself. You can read more about this
+process at :ref:`secret_generators`.
+
+With the "Secrets Import" plugin, you can upload your own list of secrets to be used instead. This is useful for
+integrating with third-party check-in systems.
+
+
+API Resource description
+-------------------------
+
+The secrets import plugin provides a HTTP API that allows you to create new secrets.
+
+The imported secret resource contains the following public fields:
+
+.. rst-class:: rest-resource-table
+
+===================================== ========================== =======================================================
+Field                                 Type                       Description
+===================================== ========================== =======================================================
+id                                    integer                    Internal ID of the secret
+secret                                string                     Actual string content of the secret (QR code content)
+used                                  boolean                    Whether the secret was already used for a ticket. If ``true``,
+                                                                 the secret can no longer be deleted. Secrets are never used
+                                                                 twice, even if an order is canceled or deleted.
+item                                  integer                    Internal ID of a product, or ``null``. If set, the secret
+                                                                 will only be used for tickets of this product.
+variation                             integer                    Internal ID of a product variation, or ``null``. If set, the secret
+                                                                 will only be used for tickets of this product variation.
+subevent                              integer                    Internal ID of an event series date, or ``null``. If set, the secret
+                                                                 will only be used for tickets of this event series date.
+===================================== ========================== =======================================================
+
+API Endpoints
+-------------
+
+.. http:get:: /api/v1/organizers/(organizer)/events/(event)/imported_secrets/
+
+   Returns a list of all secrets imported for an event.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      GET /api/v1/organizers/bigevents/events/sampleconf/imported_secrets/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: application/json
+
+      {
+        "count": 1,
+        "next": null,
+        "previous": null,
+        "results": [
+          {
+            "id": 1,
+            "secret": "foobar",
+            "used": false,
+            "item": null,
+            "variation": null,
+            "subevent": null
+          }
+        ]
+      }
+
+   :query page: The page number in case of a multi-page result set, default is 1
+   :param organizer: The ``slug`` field of a valid organizer
+   :param event: The ``slug`` field of the event to fetch
+   :statuscode 200: no error
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer or event does not exist **or** you have no permission to view it.
+
+.. http:get:: /api/v1/organizers/(organizer)/events/(event)/imported_secrets/(id)/
+
+   Returns information on one secret, identified by its ID.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      GET /api/v1/organizers/bigevents/events/sampleconf/imported_secrets/1/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: application/json
+
+      {
+        "id": 1,
+        "secret": "foobar",
+        "used": false,
+        "item": null,
+        "variation": null,
+        "subevent": null
+      }
+
+   :param organizer: The ``slug`` field of the organizer to fetch
+   :param event: The ``slug`` field of the event to fetch
+   :param id: The ``id`` field of the secret to fetch
+   :statuscode 200: no error
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event/secret does not exist **or** you have no permission to view it.
+
+.. http:post:: /api/v1/organizers/(organizer)/events/(event)/imported_secrets/
+
+   Create a new secret.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      POST /api/v1/organizers/bigevents/events/sampleconf/imported_secrets/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+      Content-Type: application/json
+      Content-Length: 166
+
+      {
+        "secret": "foobar",
+        "used": false,
+        "item": null,
+        "variation": null,
+        "subevent": null
+      }
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 201 Created
+      Vary: Accept
+      Content-Type: application/json
+
+      {
+        "id": 1,
+        "secret": "foobar",
+        "used": false,
+        "item": null,
+        "variation": null,
+        "subevent": null
+      }
+
+   :param organizer: The ``slug`` field of the organizer to a create new secret for
+   :param event: The ``slug`` field of the event to create a new secret for
+   :statuscode 201: no error
+   :statuscode 400: The secret could not be created due to invalid submitted data.
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event does not exist **or** you have no permission to create secrets.
+
+.. http:post:: /api/v1/organizers/(organizer)/events/(event)/imported_secrets/bulk_create/
+
+   Create new secrets in bulk (up to 500 per request). The request either succeeds or fails entirely.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      POST /api/v1/organizers/bigevents/events/sampleconf/imported_secrets/bulk_create/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+      Content-Type: application/json
+      Content-Length: 166
+
+      [
+        {
+          "secret": "foobar",
+          "used": false,
+          "item": null,
+          "variation": null,
+          "subevent": null
+        },
+        {
+          "secret": "baz",
+          "used": false,
+          "item": null,
+          "variation": null,
+          "subevent": null
+        }
+      ]
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: application/json
+
+      [
+        {
+          "id": 1,
+          "secret": "foobar",
+          "used": false,
+          "item": null,
+          "variation": null,
+          "subevent": null
+        },
+        {
+          "id": 2,
+          "secret": "baz",
+          "used": false,
+          "item": null,
+          "variation": null,
+          "subevent": null
+        }
+      ]
+
+   :param organizer: The ``slug`` field of the organizer to create new secrets for
+   :param event: The ``slug`` field of the event to create new secrets for
+   :statuscode 201: no error
+   :statuscode 400: The secrets could not be created due to invalid submitted data.
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event does not exist **or** you have no permission to create secrets.
+
+
+.. http:patch:: /api/v1/organizers/(organizer)/events/(event)/imported_secrets/(id)/
+
+   Update a secret. You can also use ``PUT`` instead of ``PATCH``. With ``PUT``, you have to provide all fields of
+   the resource, other fields will be reset to default. With ``PATCH``, you only need to provide the fields that you
+   want to change.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      PATCH /api/v1/organizers/bigevents/events/sampleconf/imported_secrets/1/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+      Content-Type: application/json
+      Content-Length: 34
+
+      {
+        "item": 2
+      }
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: text/javascript
+
+      {
+        "id": 1,
+        "secret": "foobar",
+        "used": false,
+        "item": 2,
+        "variation": null,
+        "subevent": null
+      }
+
+   :param organizer: The ``slug`` field of the organizer to modify
+   :param event: The ``slug`` field of the event to modify
+   :param id: The ``id`` field of the secret to modify
+   :statuscode 200: no error
+   :statuscode 400: The secret could not be modified due to invalid submitted data.
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event/secret does not exist **or** you have no permission to change it.
+
+
+.. http:delete:: /api/v1/organizers/(organizer)/events/(event)/imported_secrets/(id)/
+
+   Delete a secret. You can only delete secrets that have not yet been used.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      DELETE /api/v1/organizers/bigevents/events/sampleconf/imported_secrets/1/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 204 No Content
+      Vary: Accept
+
+   :param organizer: The ``slug`` field of the organizer to modify
+   :param event: The ``slug`` field of the event to modify
+   :param id: The ``id`` field of the secret to delete
+   :statuscode 204: no error
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event/secret does not exist **or** you have no permission to change it **or** the secret has already been used
+

doc/plugins/index.rst

@@ -17,4 +17,6 @@ If you want to **create** a plugin, please go to the
    campaigns
    certificates
    digital
+   imported_secrets
    webinar
+   presale-saml

doc/plugins/presale-saml.rst

@@ -0,0 +1,405 @@
+.. highlight:: ini
+.. spelling::
+
+   IdP
+   skIDentity
+   ePA
+   NPA
+
+Presale SAML Authentication
+===========================
+
+The Presale SAML Authentication plugin is an advanced plugin, which most event
+organizers will not need to use. However, for the select few  who do require
+strong customer authentication that cannot be covered by the built-in customer
+account functionality, this plugin allows pretix to connect to a SAML IdP and
+perform authentication and retrieval of user information.
+
+Usage of the plugin is governed by two separate sets of settings: The plugin
+installation, the Service Provider (SP) configuration and the event
+configuration.
+
+Plugin installation and initial configuration
+---------------------------------------------
+
+.. note:: If you are a customer of our hosted `pretix.eu`_ offering, you can
+          skip this section.
+
+The plugin is installed as any other plugin in the pretix ecosystem. As a
+pretix system administrator, please follow the instructions in the the
+:ref:`Administrator documentation <admindocs>`.
+
+Once installed, you will need to assess, if you want (or need) your pretix
+instance to be a single SP for all organizers and events or if every event
+organizer has to provide their own SP.
+
+Take the example of a university which runs pretix under an pretix Enterprise
+agreement. Since they only provide ticketing services to themselves (every
+organizer is still just a different department of the same university), a
+single SP should be enough.
+
+On the other hand, a reseller such as `pretix.eu`_ who services a multitude
+of clients would not work that way. Here, every organizer is a separate
+legal entity and as such will also need to provide their own SP configuration:
+Company A will expect their SP to reflect their company - and not a generalized
+"pretix SP".
+
+Once you have decided on the mode of operation, the :ref:`Configuration file
+<config>` needs to be extended to reflect your choice.
+
+Example::
+
+    [presale-saml]
+    level=global
+
+``level``
+    ``global`` to use only a single, system-wide SP, ``organizer`` for multiple
+    SPs, configured on the organizer-level. Defaults to ``organizer``.
+
+Service Provider configuration
+------------------------------
+
+Global Level
+^^^^^^^^^^^^
+
+.. note:: If you are a customer of our hosted `pretix.eu`_ offering, you can
+          skip this section and follow the instructions on the upcoming
+          Organizer Level settings.
+
+As a user with administrative privileges, please activate them by clicking the
+`Admin Mode` button in the top right hand corner.
+
+You should now see a new menu-item titled `SAML` appear.
+
+Organizer Level
+^^^^^^^^^^^^^^^
+
+Navigate to the organizer settings in the pretix backend. In the navigation
+bar, you will find a menu-item titled `SAML` if your user has the `Can
+change organizer settings` permission.
+
+
+.. note:: If you are a customer of our hosted `pretix.eu`_ offering, the menu
+          will only appear once one of our friendly customer service agents
+          has enabled the Presale SAML Authentication plugin for at least one
+          of your events. Feel free to get in touch with us!
+
+Setting up the SP
+^^^^^^^^^^^^^^^^^
+
+No matter where your SP configuration lives, you will be greeted by a very
+long list of fields of which almost all of them will need to be filled. Please
+don't be discouraged - most of the settings don't need to be decided by yourself
+and/or are already preset with a sensible default setting.
+
+If you are not sure what setting you should choose for any of the fields, you
+should reach out to your IdP operator as they can tell you exactly what the IdP
+expects and - more importantly - supports.
+
+``IdP Metadata URL``
+    Please provide the URL where your IdP outputs its metadata. For most IdPs,
+    this URL is static and the same for all SPs. If you are a member of the
+    DFN-AAI, you can find the meta-data for the `Test-, Basic- and
+    Advanced-Federation`_ on their website. Please do talk with your local
+    IdP operator though, as you might not even need to go through the DFN-AAI
+    and might just use your institutions local IdP which will also host their
+    metadata on a different URL.
+
+    The URL needs to be publicly accessible, as saving the settings form will
+    fail if the IdP metadata cannot be retrieved. pretix will also automatically
+    refresh the IdP metadata on a regular basis.
+
+``SP Entity Id``
+    By default, we recommend that you use the system-proposed metadata-URL as
+    the Entity Id of your SP. However, if so desired or required by your IdP,
+    you can also set any other, arbitrary URL as the SP Entity Id.
+
+``SP Name / SP Decription``
+    Most IdP will display the name and description of your SP to the users
+    during authentication. The description field can be used to explain to the
+    users how their data is being used.
+
+``SP X.509 Certificate / SP X.509 Private Key``
+    Your SP needs a certificate and a private key for said certificate. Please
+    coordinate with your IdP, if you are supposed to generate these yourself or
+    if they are provided to you.
+
+``SP X.509 New Certificate``
+    As certificates have an expiry date, they need to be renewed on a regular
+    basis. In order to facilitate the rollover from the expiring to the new
+    certificate, you can provide the new certificate already before the expiration
+    of the existing one. That way, the system will automatically use the correct
+    one. Once the old certificate has expired and is not used anymore at all,
+    you can move the new certificate into the slot of the normal certificate and
+    keep the new slot empty for your next renewal process.
+
+``Requested Attributes``
+    An IdP can hold a variety of attributes of an authenticating user. While
+    your IdP will dictate which of the available attributes your SP can consume
+    in theory, you will still need to define exactly which attributes the SP
+    should request.
+
+    The notation is a JSON list of objects with 5 attributes each:
+
+      * ``attributeValue``: Can be defaulted to ``[]``.
+      * ``friendlyName``: String used in the upcoming event-level settings to
+        retrieve the attributes data.
+      * ``isRequired``: Boolean indicating whether the IdP must enforce the
+        transmission of this attribute. In most cases, ``true`` is the best
+        choice.
+      * ``name``: String of the internal, technical name of the requested
+        attribute. Often starting with ``urn:mace:dir:attribute-def:``,
+        ``urn:oid:`` or ``http://``/``https://``.
+      * ``nameFormat``: String describing the type of ``name`` that has been
+        set in the previous section. Often starting with
+        ``urn:mace:shibboleth:1.0:`` or ``urn:oasis:names:tc:SAML:2.0:``.
+
+    Your IdP can provide you with a list of available attributes. See below
+    for a sample configuration in an academic context.
+
+    Note, that you can have multiple attributes with the same ``friendlyName``
+    but different ``name``s. This is often used in systems, where the same
+    information (for example a persons name) is saved in different fields -
+    for example because one institution is returning SAML 1.0 and other
+    institutions are returning SAML 2.0 style attributes. Typically, this only
+    occurs in mix environments like the DFN-AAI with a large number of
+    participants. If you are only using your own institutions IdP and not
+    authenticating anyone outside of your realm, this should not be a common
+    sight.
+
+``Encrypt/Sign/Require ...``
+    Does what is says on the box - please inquire with your IdP for the
+    necessary settings. Most settings can be turned on as they increase security,
+    however some IdPs might stumble over some of them.
+
+``Signature / Digest Algorithm``
+    Please chose appropriate algorithms, that both pretix/your SP and the IdP
+    can communicate with. A common source of issues when connecting to a
+    Shibboleth-based IdP is the Digest Algorithm: pretix does not support
+    ``http://www.w3.org/2009/xmlenc11#rsa-oaep`` and authentication will fail
+    if the IdP enforces this.
+
+``Technical/Support Contacts``
+    Those contacts are encoded into the SPs public meta data and might be
+    displayed to users having trouble authenticating. It is recommended to
+    provide a dedicated point of contact for technical issues, as those will
+    be the ones to change the configuration for the SP.
+
+Event / Authentication configuration
+------------------------------------
+
+Basic settings
+^^^^^^^^^^^^^^
+
+Once the plugin has been enabled for a pretix event using the Plugins-menu from
+the event's settings, a new *SAML* menu item will show up.
+
+On this page, the actual authentication can be configured.
+
+``Checkout Explanation``
+    Since most users probably won't be familiar with why they have to authenticate
+    to buy a ticket, you can provide them a small blurb here. Markdown is supported.
+
+``Attribute RegEx``
+    By default, any successful authentication with the IdP will allow the user to
+    proceed with their purchase. Should the allowed audience needed to be restricted
+    further, a set of regular Expressions can be used to do this.
+
+    An Attribute RegEx of ``{}`` will allow any authenticated user to pass.
+
+    A RegEx of ``{ "affiliation": "^(employee@pretix.eu|staff@pretix.eu)$" }`` will
+    only allow user to pass which have the ``affiliation`` attribute and whose
+    attribute either matches ``employee@pretix.eu`` or ``staff@pretix.eu``.
+
+    Please make sure that the attribute you are querying is also requested from the
+    IdP in the first place - for a quick check you can have a look at the top of
+    the page where all currently configured attributes are listed.
+
+``RegEx Fail Explanation``
+    Only used in conjunction with the above Attribute RegEx. Should the user not
+    pass the restrictions imposed by the regular expression, the user is shown
+    this error-message.
+
+    If you are - for example in an university context - restricting access to
+    students only, you might want to explain here that Employees are not allowed
+    to book tickets.
+
+``Ticket Secret SAML Attribute``
+    In very specific instances, it might be desirable that the ticket-secret is
+    not the randomly one generated by pretix but rather based on one of the
+    users attributes - for example their unique ID or access card number.
+
+    To achieve this, the name of a SAML-attribute can be specified here.
+
+    It is however necessary to note, that even with this setting in use,
+    ticket-secrets need to be unique. This is why when this setting is enabled,
+    the default, pretix-generated ticket-secret is prefixed with the attributes
+    value.
+
+    Example: A users ``cardid`` attribute has the value of ``01189998819991197253``.
+    The default random ticket secret would have been
+    ``yczygpw9877akz2xwdhtdyvdqwkv7npj``. The resulting new secret will now be
+    ``01189998819991197253_yczygpw9877akz2xwdhtdyvdqwkv7npj``.
+
+    That way, the ticket secret is still unique, but when checking into an event,
+    the user can easily be searched and found using their identifier.
+
+IdP-provided E-Mail addresses, names
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+By default, pretix will only authenticate the user and not process the received
+data any further.
+
+However, there are a few exceptions to this rule.
+
+There are a few `magic` attributes that pretix will use to automatically populate
+the corresponding fields within the checkout process **and lock them out from
+user editing**.
+
+  * ``givenName`` and ``sn``: If both of those attributes are present and pretix
+    is configured to collect the users name, these attributes' values are used
+    for the given and family name respectively.
+  * ``email``: If this attribute is present, the E-Mail-address of the users will
+    be set to the one transmitted through the attributes.
+
+The latter might pose a problem, if the IdP is transmitting an ``email`` attribute
+which does contain a system-level mail address which is only used as an internal
+identifier but not as a real mailbox. In this case, please consider setting the
+``friendlyName`` of the attribute to a different value than ``email`` or removing
+this field from the list of requested attributes altogether.
+
+Saving attributes to questions
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+By setting the ``internal identifier`` of a user-defined question to the same name
+as a SAML attribute, pretix will save the value of said attribute into the question.
+
+All the same as in the above section on E-Mail addresses, those fields become
+non-editable by the user.
+
+Please be aware that some specialty question types might not be compatible with
+the SAML attributes due to specific format requirements. If in doubt (or if the
+checkout fails/the information is not properly saved), try setting the question
+type to a simple type like "Text (one line)".
+
+Notes and configuration examples
+--------------------------------
+
+Requesting SAML 1.0 and 2.0 attributes from an academic IdP
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This requests the ``eduPersonPrincipalName`` (also sometimes called EPPN),
+``email``, ``givenName`` and ``sn`` both in SAML 1.0 and SAML 2.0 attributes.
+
+.. sourcecode:: json
+
+    [
+        {
+            "attributeValue": [],
+            "friendlyName": "eduPersonPrincipalName",
+            "isRequired": true,
+            "name": "urn:mace:dir:attribute-def:eduPersonPrincipalName",
+            "nameFormat": "urn:mace:shibboleth:1.0:attributeNamespace:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "eduPersonPrincipalName",
+            "isRequired": true,
+            "name": "urn:oid:1.3.6.1.4.1.5923.1.1.1.6",
+            "nameFormat": "urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "email",
+            "isRequired": true,
+            "name": "urn:mace:dir:attribute-def:mail",
+            "nameFormat": "urn:mace:shibboleth:1.0:attributeNamespace:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "email",
+            "isRequired": true,
+            "name": "urn:oid:0.9.2342.19200300.100.1.3",
+            "nameFormat": "urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "givenName",
+            "isRequired": true,
+            "name": "urn:mace:dir:attribute-def:givenName",
+            "nameFormat": "urn:mace:shibboleth:1.0:attributeNamespace:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "givenName",
+            "isRequired": true,
+            "name": "urn:oid:2.5.4.42",
+            "nameFormat": "urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "sn",
+            "isRequired": true,
+            "name": "urn:mace:dir:attribute-def:sn",
+            "nameFormat": "urn:mace:shibboleth:1.0:attributeNamespace:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "sn",
+            "isRequired": true,
+            "name": "urn:oid:2.5.4.4",
+            "nameFormat": "urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
+        }
+    ]
+
+skIDentity IdP Metadata URL
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Since the IdP Metadata URL for `skIDentity`_ is not readily documented/visible
+in their backend, we document it here:
+``https://service.skidentity.de/fs/saml/metadata``
+
+Requesting skIDentity attributes for electronic identity cards
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This requests the basic ``eIdentifier``, ``IDType``, ``IDIssuer``, and
+``NameID`` from the `skIDentity`_ SAML service, which are available for
+electronic ID cards such as the German ePA/NPA. (Other attributes such as
+the name and address are available at additional cost from the IdP).
+
+.. sourcecode:: json
+
+    [
+        {
+            "attributeValue": [],
+            "friendlyName": "eIdentifier",
+            "isRequired": true,
+            "name": "http://www.skidentity.de/att/eIdentifier",
+            "nameFormat": "urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "IDType",
+            "isRequired": true,
+            "name": "http://www.skidentity.de/att/IDType",
+            "nameFormat": "urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "IDIssuer",
+            "isRequired": true,
+            "name": "http://www.skidentity.de/att/IDIssuer",
+            "nameFormat": "urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
+        },
+        {
+            "attributeValue": [],
+            "friendlyName": "NameID",
+            "isRequired": true,
+            "name": "http://www.skidentity.de/att/NameID",
+            "nameFormat": "urn:oasis:names:tc:SAML:2.0:attrname-format:uri"
+        }
+    ]
+
+.. _pretix.eu: https://pretix.eu
+.. _Test-, Basic- and Advanced-Federation: https://doku.tid.dfn.de/en:metadata
+.. _skIDentity: https://www.skidentity.de/

doc/spelling_wordlist.txt

@@ -17,6 +17,7 @@ bic
 BIC
 boolean
 booleans
+bugfix
 cancelled
 casted
 Ceph
@@ -77,6 +78,7 @@ mixin
 mixins
 multi
 multidomain
+multiplicator
 namespace
 namespaced
 namespaces

doc/user/events/email.rst

@@ -203,4 +203,4 @@ Then, please contact support@pretix.eu and we will enable DKIM for your domain o
 
 
 .. _Sender Policy Framework: https://en.wikipedia.org/wiki/Sender_Policy_Framework
-.. _SPF specification: http://www.openspf.org/SPF_Record_Syntax
+.. _SPF specification: http://www.open-spf.org/SPF_Record_Syntax

doc/user/events/ticket_secrets.rst

@@ -1,3 +1,5 @@
+.. _secret_generators:
+
 Ticket secret generators
 ========================
 

doc/user/events/widget.rst

@@ -309,6 +309,10 @@ Currently, the following attributes are understood by pretix itself:
   always be modified. Note that this is not a security feature and can easily be overridden by users, so do not rely
   on this for authentication.
 
+* If ``data-consent="…"`` is given, the cookie consent mechanism will be initialized with consent for the given cookie
+  providers. All other providers will be disabled, no consent dialog will be shown. This is useful if you already
+  asked the user for consent and don't want them to be asked again. Example: ``data-consent="facebook,google_analytics"``
+
 Any configured pretix plugins might understand more data fields. For example, if the appropriate plugins on pretix
 Hosted or pretix Enterprise are active, you can pass the following fields:
 

src/.update-locales

@@ -34,5 +34,7 @@ git push
 # Unlock Weblate
 for c in $COMPONENTS; do
 	wlc unlock $c;
+done
+for c in $COMPONENTS; do
 	wlc pull $c;
 done

src/pretix/__init__.py

@@ -19,4 +19,4 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
-__version__ = "4.3.0"
+__version__ = "4.7.0"

src/pretix/api/auth/devicesecurity.py

@@ -167,6 +167,8 @@ class PretixPosSecurityProfile(AllowListSecurityProfile):
         ('GET', 'api-v1:checkinlist-list'),
         ('POST', 'api-v1:checkinlistpos-redeem'),
         ('POST', 'plugins:pretix_posbackend:order.posprintlog'),
+        ('POST', 'plugins:pretix_posbackend:order.poslock'),
+        ('DELETE', 'plugins:pretix_posbackend:order.poslock'),
         ('DELETE', 'api-v1:cartposition-detail'),
         ('GET', 'api-v1:giftcard-list'),
         ('POST', 'api-v1:giftcard-transact'),
@@ -174,6 +176,8 @@ class PretixPosSecurityProfile(AllowListSecurityProfile):
         ('POST', 'plugins:pretix_posbackend:posreceipt-list'),
         ('POST', 'plugins:pretix_posbackend:posclosing-list'),
         ('POST', 'plugins:pretix_posbackend:posdebugdump-list'),
+        ('POST', 'plugins:pretix_posbackend:posdebuglogentry-list'),
+        ('POST', 'plugins:pretix_posbackend:posdebuglogentry-bulk-create'),
         ('GET', 'plugins:pretix_posbackend:poscashier-list'),
         ('POST', 'plugins:pretix_posbackend:stripeterminal.token'),
         ('GET', 'api-v1:revokedsecrets-list'),

src/pretix/api/serializers/checkin.py

@@ -60,7 +60,7 @@ class CheckinListSerializer(I18nAwareModelSerializer):
         full_data = self.to_internal_value(self.to_representation(self.instance)) if self.instance else {}
         full_data.update(data)
 
-        for item in full_data.get('limit_products'):
+        for item in full_data.get('limit_products', []):
             if event != item.event:
                 raise ValidationError(_('One or more items do not belong to this event.'))
 

src/pretix/api/serializers/event.py

@@ -637,7 +637,7 @@ class SubEventSerializer(I18nAwareModelSerializer):
 class TaxRuleSerializer(CountryFieldMixin, I18nAwareModelSerializer):
     class Meta:
         model = TaxRule
-        fields = ('id', 'name', 'rate', 'price_includes_tax', 'eu_reverse_charge', 'home_country')
+        fields = ('id', 'name', 'rate', 'price_includes_tax', 'eu_reverse_charge', 'home_country', 'internal_name', 'keep_gross_if_rate_changes')
 
 
 class EventSettingsSerializer(SettingsSerializer):
@@ -704,6 +704,7 @@ class EventSettingsSerializer(SettingsSerializer):
         'payment_term_accept_late',
         'payment_explanation',
         'payment_pending_hidden',
+        'mail_days_order_expire_warning',
         'ticket_download',
         'ticket_download_date',
         'ticket_download_addons',
@@ -712,7 +713,6 @@ class EventSettingsSerializer(SettingsSerializer):
         'ticket_download_require_validated_email',
         'ticket_secret_length',
         'mail_prefix',
-        'mail_from',
         'mail_from_name',
         'mail_attach_ical',
         'mail_attach_tickets',
@@ -733,6 +733,7 @@ class EventSettingsSerializer(SettingsSerializer):
         'invoice_numbers_prefix_cancellations',
         'invoice_numbers_counter_length',
         'invoice_attendee_name',
+        'invoice_event_location',
         'invoice_include_expire_date',
         'invoice_address_explanation_text',
         'invoice_email_attachment',
@@ -762,6 +763,7 @@ class EventSettingsSerializer(SettingsSerializer):
         'cancel_allow_user_paid_refund_as_giftcard',
         'cancel_allow_user_paid_require_approval',
         'change_allow_user_variation',
+        'change_allow_user_addons',
         'change_allow_user_until',
         'change_allow_user_price',
         'primary_color',

src/pretix/api/serializers/item.py

@@ -58,8 +58,9 @@ class InlineItemVariationSerializer(I18nAwareModelSerializer):
     class Meta:
         model = ItemVariation
         fields = ('id', 'value', 'active', 'description',
-                  'position', 'default_price', 'price', 'original_price',
-                  'require_membership', 'require_membership_types', 'available_from', 'available_until',
+                  'position', 'default_price', 'price', 'original_price', 'require_approval',
+                  'require_membership', 'require_membership_types',
+                  'require_membership_hidden', 'available_from', 'available_until',
                   'sales_channels', 'hide_without_voucher',)
 
     def __init__(self, *args, **kwargs):
@@ -74,8 +75,9 @@ class ItemVariationSerializer(I18nAwareModelSerializer):
     class Meta:
         model = ItemVariation
         fields = ('id', 'value', 'active', 'description',
-                  'position', 'default_price', 'price', 'original_price',
-                  'require_membership', 'require_membership_types', 'available_from', 'available_until',
+                  'position', 'default_price', 'price', 'original_price', 'require_approval',
+                  'require_membership', 'require_membership_types',
+                  'require_membership_hidden', 'available_from', 'available_until',
                   'sales_channels', 'hide_without_voucher',)
 
     def __init__(self, *args, **kwargs):
@@ -175,7 +177,7 @@ class ItemSerializer(I18nAwareModelSerializer):
                   'min_per_order', 'max_per_order', 'checkin_attention', 'has_variations', 'variations',
                   'addons', 'bundles', 'original_price', 'require_approval', 'generate_tickets',
                   'show_quota_left', 'hidden_if_available', 'allow_waitinglist', 'issue_giftcard', 'meta_data',
-                  'require_membership', 'require_membership_types', 'grant_membership_type',
+                  'require_membership', 'require_membership_types', 'require_membership_hidden', 'grant_membership_type',
                   'grant_membership_duration_like_event', 'grant_membership_duration_days',
                   'grant_membership_duration_months')
         read_only_fields = ('has_variations',)
@@ -249,9 +251,12 @@ class ItemSerializer(I18nAwareModelSerializer):
         bundles_data = validated_data.pop('bundles') if 'bundles' in validated_data else {}
         meta_data = validated_data.pop('meta_data', None)
         picture = validated_data.pop('picture', None)
+        require_membership_types = validated_data.pop('require_membership_types', [])
         item = Item.objects.create(**validated_data)
         if picture:
             item.picture.save(os.path.basename(picture.name), picture)
+        if require_membership_types:
+            item.require_membership_types.add(*require_membership_types)
 
         for variation_data in variations_data:
             require_membership_types = variation_data.pop('require_membership_types', [])

src/pretix/api/serializers/order.py

@@ -934,7 +934,8 @@ class OrderCreateSerializer(I18nAwareModelSerializer):
     consume_carts = serializers.ListField(child=serializers.CharField(), required=False)
     force = serializers.BooleanField(default=False, required=False)
     payment_date = serializers.DateTimeField(required=False, allow_null=True)
-    send_email = serializers.BooleanField(default=False, required=False)
+    send_email = serializers.BooleanField(default=False, required=False, allow_null=True)
+    require_approval = serializers.BooleanField(default=False, required=False)
     simulate = serializers.BooleanField(default=False, required=False)
     customer = serializers.SlugRelatedField(slug_field='identifier', queryset=Customer.objects.none(), required=False)
 
@@ -947,7 +948,7 @@ class OrderCreateSerializer(I18nAwareModelSerializer):
         model = Order
         fields = ('code', 'status', 'testmode', 'email', 'phone', 'locale', 'payment_provider', 'fees', 'comment', 'sales_channel',
                   'invoice_address', 'positions', 'checkin_attention', 'payment_info', 'payment_date', 'consume_carts',
-                  'force', 'send_email', 'simulate', 'customer', 'custom_followup_at')
+                  'force', 'send_email', 'simulate', 'customer', 'custom_followup_at', 'require_approval')
 
     def validate_payment_provider(self, pp):
         if pp is None:
@@ -1041,6 +1042,8 @@ class OrderCreateSerializer(I18nAwareModelSerializer):
         force = validated_data.pop('force', False)
         simulate = validated_data.pop('simulate', False)
         self._send_mail = validated_data.pop('send_email', False)
+        if self._send_mail is None:
+            self._send_mail = validated_data.get('sales_channel') in self.context['event'].settings.mail_sales_channel_placed_paid
 
         if 'invoice_address' in validated_data:
             iadata = validated_data.pop('invoice_address')
@@ -1219,6 +1222,8 @@ class OrderCreateSerializer(I18nAwareModelSerializer):
             order.set_expires(subevents=[p.get('subevent') for p in positions_data])
             order.meta_info = "{}"
             order.total = Decimal('0.00')
+            if validated_data.get('require_approval') is not None:
+                order.require_approval = validated_data['require_approval']
             if simulate:
                 order = WrappedModel(order)
                 order.last_modified = now()
@@ -1404,6 +1409,7 @@ class OrderCreateSerializer(I18nAwareModelSerializer):
                 state=OrderPayment.PAYMENT_STATE_CREATED
             )
 
+        order.create_transactions(is_new=True, fees=fees, positions=pos_map.values())
         return order
 
 
@@ -1425,9 +1431,9 @@ class InlineInvoiceLineSerializer(I18nAwareModelSerializer):
 
     class Meta:
         model = InvoiceLine
-        fields = ('position', 'description', 'item', 'variation', 'attendee_name', 'event_date_from',
+        fields = ('position', 'description', 'item', 'variation', 'subevent', 'attendee_name', 'event_date_from',
                   'event_date_to', 'gross_value', 'tax_value', 'tax_rate', 'tax_name', 'fee_type',
-                  'fee_internal_type')
+                  'fee_internal_type', 'event_location')
 
 
 class InvoiceSerializer(I18nAwareModelSerializer):

src/pretix/api/serializers/organizer.py

@@ -296,7 +296,14 @@ class OrganizerSettingsSerializer(SettingsSerializer):
         'theme_round_borders',
         'primary_font',
         'organizer_logo_image_inherit',
-        'organizer_logo_image'
+        'organizer_logo_image',
+        'privacy_url',
+        'cookie_consent',
+        'cookie_consent_dialog_title',
+        'cookie_consent_dialog_text',
+        'cookie_consent_dialog_text_secondary',
+        'cookie_consent_dialog_button_yes',
+        'cookie_consent_dialog_button_no',
     ]
 
     def __init__(self, *args, **kwargs):

src/pretix/api/views/checkin.py

@@ -430,7 +430,13 @@ class CheckinListPositionViewSet(viewsets.ReadOnlyModelViewSet):
             if self.kwargs['pk'].isnumeric():
                 op = queryset.get(Q(pk=self.kwargs['pk']) | Q(secret=self.kwargs['pk']))
             else:
-                op = queryset.get(secret=self.kwargs['pk'])
+                # In application/x-www-form-urlencoded, you can encodes space ' ' with '+' instead of '%20'.
+                # `id`, however, is part of a path where this technically is not allowed. Old versions of our
+                # scan apps still do it, so we try work around it!
+                try:
+                    op = queryset.get(secret=self.kwargs['pk'])
+                except OrderPosition.DoesNotExist:
+                    op = queryset.get(secret=self.kwargs['pk'].replace('+', ' '))
         except OrderPosition.DoesNotExist:
             revoked_matches = list(self.request.event.revoked_secrets.filter(secret=self.kwargs['pk']))
             if len(revoked_matches) == 0:

src/pretix/api/views/exporters.py

@@ -69,7 +69,7 @@ class ExportersMixin:
         cf = get_object_or_404(CachedFile, id=kwargs['cfid'])
         if cf.file:
             resp = ChunkBasedFileResponse(cf.file.file, content_type=cf.type)
-            resp['Content-Disposition'] = 'attachment; filename="{}"'.format(cf.filename)
+            resp['Content-Disposition'] = 'attachment; filename="{}"'.format(cf.filename).encode("ascii", "ignore")
             return resp
         elif not settings.HAS_CELERY:
             return Response(
@@ -132,7 +132,7 @@ class EventExportersViewSet(ExportersMixin, viewsets.ViewSet):
     def exporters(self):
         exporters = []
         responses = register_data_exporters.send(self.request.event)
-        for ex in sorted([response(self.request.event, self.request.organizer) for r, response in responses], key=lambda ex: str(ex.verbose_name)):
+        for ex in sorted([response(self.request.event, self.request.organizer) for r, response in responses if response], key=lambda ex: str(ex.verbose_name)):
             ex._serializer = JobRunSerializer(exporter=ex)
             exporters.append(ex)
         return exporters

src/pretix/api/views/order.py

@@ -92,6 +92,9 @@ with scopes_disabled():
         subevent_after = django_filters.IsoDateTimeFilter(method='subevent_after_qs')
         subevent_before = django_filters.IsoDateTimeFilter(method='subevent_before_qs')
         search = django_filters.CharFilter(method='search_qs')
+        item = django_filters.CharFilter(field_name='all_positions', lookup_expr='item_id')
+        variation = django_filters.CharFilter(field_name='all_positions', lookup_expr='variation_id')
+        subevent = django_filters.CharFilter(field_name='all_positions', lookup_expr='subevent_id')
 
         class Meta:
             model = Order
@@ -214,7 +217,9 @@ class OrderViewSet(viewsets.ModelViewSet):
                     'positions',
                     opq.all().prefetch_related(
                         Prefetch('checkins', queryset=Checkin.objects.all()),
-                        'item', 'variation', 'answers', 'answers__options', 'answers__question', 'seat',
+                        'item', 'variation',
+                        Prefetch('answers', queryset=QuestionAnswer.objects.prefetch_related('options', 'question').order_by('question__position')),
+                        'seat',
                     )
                 )
             )
@@ -641,7 +646,11 @@ class OrderViewSet(viewsets.ModelViewSet):
                     payment and order.total == Decimal('0.00') and order.status == Order.STATUS_PAID and
                     not order.require_approval and payment.provider == "free"
                 )
-                if free_flow:
+                if order.require_approval:
+                    email_template = request.event.settings.mail_text_order_placed_require_approval
+                    log_entry = 'pretix.event.order.email.order_placed_require_approval'
+                    email_attendees = False
+                elif free_flow:
                     email_template = request.event.settings.mail_text_order_free
                     log_entry = 'pretix.event.order.email.order_free'
                     email_attendees = request.event.settings.mail_send_order_free_attendee
@@ -654,12 +663,13 @@ class OrderViewSet(viewsets.ModelViewSet):
 
                 _order_placed_email(
                     request.event, order, payment.payment_provider if payment else None, email_template,
-                    log_entry, invoice, payment
+                    log_entry, invoice, payment, is_free=free_flow
                 )
                 if email_attendees:
                     for p in order.positions.all():
                         if p.addon_to_id is None and p.attendee_email and p.attendee_email != order.email:
-                            _order_placed_email_attendee(request.event, order, p, email_attendees_template, log_entry)
+                            _order_placed_email_attendee(request.event, order, p, email_attendees_template, log_entry,
+                                                         is_free=free_flow)
 
                 if not free_flow and order.status == Order.STATUS_PAID and payment:
                     payment._send_paid_mail(invoice, None, '')

src/pretix/base/apps.py

@@ -47,6 +47,7 @@ class PretixBaseConfig(AppConfig):
         from . import notifications  # NOQA
         from . import email  # NOQA
         from .services import auth, checkin, export, mail, tickets, cart, orderimport, orders, invoices, cleanup, update_check, quotas, notifications, vouchers  # NOQA
+        from .models import _transactions  # NOQA
         from django.conf import settings
 
         try:

src/pretix/base/auth.py

@@ -94,6 +94,9 @@ class BaseAuthBackend:
         This method will be called after the user filled in the login form. ``request`` will contain
         the current request and ``form_data`` the input for the form fields defined in ``login_form_fields``.
         You are expected to either return a ``User`` object (if login was successful) or ``None``.
+
+        You are expected to either return a ``User`` object (if login was successful) or ``None``. You should
+        obtain this user object using ``User.objects.get_or_create_for_backend``.
         """
         return
 
@@ -104,7 +107,9 @@ class BaseAuthBackend:
         reverse proxy, you can directly return a ``User`` object that will be logged in.
 
         ``request`` will contain the current request.
-        You are expected to either return a ``User`` object (if login was successful) or ``None``.
+
+        You are expected to either return a ``User`` object (if login was successful) or ``None``. You should
+        obtain this user object using ``User.objects.get_or_create_for_backend``.
         """
         return
 
@@ -146,7 +151,8 @@ class NativeAuthBackend(BaseAuthBackend):
         d = OrderedDict([
             ('email', forms.EmailField(label=_("E-mail"), max_length=254,
                                        widget=forms.EmailInput(attrs={'autofocus': 'autofocus'}))),
-            ('password', forms.CharField(label=_("Password"), widget=forms.PasswordInput)),
+            ('password', forms.CharField(label=_("Password"), widget=forms.PasswordInput,
+                                         max_length=4096)),
         ])
         return d
 

src/pretix/base/email.py

@@ -25,6 +25,7 @@ from datetime import timedelta
 from decimal import Decimal
 from itertools import groupby
 from smtplib import SMTPResponseException
+from typing import TypeVar
 
 import css_inline
 from django.conf import settings
@@ -32,6 +33,7 @@ from django.core.mail.backends.smtp import EmailBackend
 from django.db.models import Count
 from django.dispatch import receiver
 from django.template.loader import get_template
+from django.utils.formats import date_format
 from django.utils.timezone import now
 from django.utils.translation import (
     get_language, gettext_lazy as _, pgettext_lazy,
@@ -49,23 +51,23 @@ from pretix.base.templatetags.rich_text import markdown_compile_email
 
 logger = logging.getLogger('pretix.base.email')
 
+T = TypeVar("T", bound=EmailBackend)
 
-class CustomSMTPBackend(EmailBackend):
 
-    def test(self, from_addr):
-        try:
-            self.open()
-            self.connection.ehlo_or_helo_if_needed()
-            (code, resp) = self.connection.mail(from_addr, [])
-            if code != 250:
-                logger.warn('Error testing mail settings, code %d, resp: %s' % (code, resp))
-                raise SMTPResponseException(code, resp)
-            (code, resp) = self.connection.rcpt('testdummy@pretix.eu')
-            if (code != 250) and (code != 251):
-                logger.warn('Error testing mail settings, code %d, resp: %s' % (code, resp))
-                raise SMTPResponseException(code, resp)
-        finally:
-            self.close()
+def test_custom_smtp_backend(backend: T, from_addr: str) -> None:
+    try:
+        backend.open()
+        backend.connection.ehlo_or_helo_if_needed()
+        (code, resp) = backend.connection.mail(from_addr, [])
+        if code != 250:
+            logger.warning('Error testing mail settings, code %d, resp: %s' % (code, resp))
+            raise SMTPResponseException(code, resp)
+        (code, resp) = backend.connection.rcpt('testdummy@pretix.eu')
+        if (code != 250) and (code != 251):
+            logger.warning('Error testing mail settings, code %d, resp: %s' % (code, resp))
+            raise SMTPResponseException(code, resp)
+    finally:
+        backend.close()
 
 
 class BaseHTMLMailRenderer:
@@ -163,9 +165,20 @@ class TemplateBasedMailRenderer(BaseHTMLMailRenderer):
                 has_addons=Count('addons')
             ))
             htmlctx['cart'] = [(k, list(v)) for k, v in groupby(
-                positions, key=lambda op: (
-                    op.item, op.variation, op.subevent, op.attendee_name,
-                    (op.pk if op.addon_to_id else None), (op.pk if op.has_addons else None)
+                sorted(
+                    positions,
+                    key=lambda op: (
+                        (op.addon_to.positionid if op.addon_to_id else op.positionid),
+                        op.positionid
+                    )
+                ),
+                key=lambda op: (
+                    op.item,
+                    op.variation,
+                    op.subevent,
+                    op.attendee_name,
+                    (op.pk if op.addon_to_id else None),
+                    (op.pk if op.has_addons else None)
                 )
             )]
 
@@ -452,6 +465,15 @@ def base_placeholders(sender, **kwargs):
                 }
             ),
         ),
+        SimpleFunctionalMailTextPlaceholder(
+            'event_location', ['event_or_subevent'], lambda event_or_subevent: str(event_or_subevent.location or ''),
+            lambda event: str(event.location or ''),
+        ),
+        SimpleFunctionalMailTextPlaceholder(
+            'event_admission_time', ['event_or_subevent'],
+            lambda event_or_subevent: date_format(event_or_subevent.date_admission, 'TIME_FORMAT') if event_or_subevent.date_admission else '',
+            lambda event: date_format(event.date_admission, 'TIME_FORMAT') if event.date_admission else '',
+        ),
         SimpleFunctionalMailTextPlaceholder(
             'subevent', ['waiting_list_entry', 'event'],
             lambda waiting_list_entry, event: str(waiting_list_entry.subevent or event),
@@ -539,6 +561,22 @@ def base_placeholders(sender, **kwargs):
             'voucher_list', ['voucher_list'], lambda voucher_list: '  \n'.join(voucher_list),
             '    68CYU2H6ZTP3WLK5\n    7MB94KKPVEPSMVF2'
         ),
+        SimpleFunctionalMailTextPlaceholder(
+            # join vouchers with two spaces at end of line so markdown-parser inserts a <br>
+            'voucher_url_list', ['event', 'voucher_list'],
+            lambda event, voucher_list: '  \n'.join([
+                build_absolute_uri(
+                    event, 'presale:event.redeem'
+                ) + '?voucher=' + c
+                for c in voucher_list
+            ]),
+            lambda event: '  \n'.join([
+                build_absolute_uri(
+                    event, 'presale:event.redeem'
+                ) + '?voucher=' + c
+                for c in ['68CYU2H6ZTP3WLK5', '7MB94KKPVEPSMVF2']
+            ]),
+        ),
         SimpleFunctionalMailTextPlaceholder(
             'url', ['event', 'voucher_list'], lambda event, voucher_list: build_absolute_uri(event, 'presale:event.index', kwargs={
                 'event': event.slug,
@@ -605,6 +643,10 @@ def base_placeholders(sender, **kwargs):
             'meta_%s' % k, ['event'], lambda event, k=k: event.meta_data[k],
             v
         ))
+        ph.append(SimpleFunctionalMailTextPlaceholder(
+            'meta_%s' % k, ['event_or_subevent'], lambda event_or_subevent, k=k: event_or_subevent.meta_data[k],
+            v
+        ))
 
     return ph
 

src/pretix/base/exporters/invoices.py

@@ -324,7 +324,6 @@ class InvoiceDataExporter(InvoiceExporterMixin, MultiSheetListExporter):
                 _('Tax rate'),
                 _('Tax name'),
                 _('Event start date'),
-
                 _('Date'),
                 _('Order code'),
                 _('E-mail address'),
@@ -348,6 +347,8 @@ class InvoiceDataExporter(InvoiceExporterMixin, MultiSheetListExporter):
                 _('Invoice recipient:') + ' ' + _('Beneficiary'),
                 _('Invoice recipient:') + ' ' + _('Internal reference'),
                 _('Payment providers'),
+                _('Event end date'),
+                _('Location'),
             ]
 
             p_providers = OrderPayment.objects.filter(
@@ -406,7 +407,9 @@ class InvoiceDataExporter(InvoiceExporterMixin, MultiSheetListExporter):
                     ', '.join([
                         str(self.providers.get(p, p)) for p in sorted(set((l.payment_providers or '').split(',')))
                         if p and p != 'free'
-                    ])
+                    ]),
+                    date_format(l.event_date_to, "SHORT_DATE_FORMAT") if l.event_date_to else "",
+                    l.event_location or "",
                 ]
 
     @cached_property

src/pretix/base/exporters/json.py

@@ -55,16 +55,20 @@ class JSONExporter(BaseExporter):
                     'name': str(self.event.organizer.name),
                     'slug': self.event.organizer.slug
                 },
+                'meta_data': self.event.meta_data,
                 'categories': [
                     {
                         'id': category.id,
                         'name': str(category.name),
+                        'description': str(category.description),
+                        'position': category.position,
                         'internal_name': category.internal_name
                     } for category in self.event.categories.all()
                 ],
                 'items': [
                     {
                         'id': item.id,
+                        'position': item.position,
                         'name': str(item.name),
                         'internal_name': str(item.internal_name),
                         'category': item.category_id,
@@ -73,13 +77,35 @@ class JSONExporter(BaseExporter):
                         'tax_name': str(item.tax_rule.name) if item.tax_rule else None,
                         'admission': item.admission,
                         'active': item.active,
+                        'sales_channels': item.sales_channels,
+                        'description': str(item.description),
+                        'available_from': item.available_from,
+                        'available_until': item.available_until,
+                        'require_voucher': item.require_voucher,
+                        'hide_without_voucher': item.hide_without_voucher,
+                        'allow_cancel': item.allow_cancel,
+                        'require_bundling': item.require_bundling,
+                        'min_per_order': item.min_per_order,
+                        'max_per_order': item.max_per_order,
+                        'checkin_attention': item.checkin_attention,
+                        'original_price': item.original_price,
+                        'issue_giftcard': item.issue_giftcard,
+                        'meta_data': item.meta_data,
+                        'require_membership': item.require_membership,
                         'variations': [
                             {
                                 'id': variation.id,
                                 'active': variation.active,
                                 'price': variation.default_price if variation.default_price is not None else
                                 item.default_price,
-                                'name': str(variation)
+                                'name': str(variation),
+                                'description': str(variation.description),
+                                'position': variation.position,
+                                'require_membership': variation.require_membership,
+                                'sales_channels': variation.sales_channels,
+                                'available_from': variation.available_from,
+                                'available_until': variation.available_until,
+                                'hide_without_voucher': variation.hide_without_voucher,
                             } for variation in item.variations.all()
                         ]
                     } for item in self.event.items.select_related('tax_rule').prefetch_related('variations')
@@ -87,7 +113,13 @@ class JSONExporter(BaseExporter):
                 'questions': [
                     {
                         'id': question.id,
+                        'identifier': question.identifier,
+                        'required': question.required,
                         'question': str(question.question),
+                        'position': question.position,
+                        'hidden': question.hidden,
+                        'ask_during_checkin': question.ask_during_checkin,
+                        'help_text': str(question.help_text),
                         'type': question.type
                     } for question in self.event.questions.all()
                 ],
@@ -95,7 +127,18 @@ class JSONExporter(BaseExporter):
                     {
                         'code': order.code,
                         'status': order.status,
+                        'customer': order.customer.identifier if order.customer else None,
+                        'testmode': order.testmode,
                         'user': order.email,
+                        'email': order.email,
+                        'phone': str(order.phone),
+                        'locale': order.locale,
+                        'comment': order.comment,
+                        'custom_followup_at': order.custom_followup_at,
+                        'require_approval': order.require_approval,
+                        'checkin_attention': order.checkin_attention,
+                        'sales_channel': order.sales_channel,
+                        'expires': order.expires,
                         'datetime': order.datetime,
                         'fees': [
                             {
@@ -108,11 +151,21 @@ class JSONExporter(BaseExporter):
                         'positions': [
                             {
                                 'id': position.id,
+                                'positionid': position.positionid,
                                 'item': position.item_id,
                                 'variation': position.variation_id,
+                                'subevent': position.subevent_id,
+                                'seat': position.seat.seat_guid if position.seat else None,
                                 'price': position.price,
+                                'tax_rate': position.tax_rate,
+                                'tax_value': position.tax_value,
                                 'attendee_name': position.attendee_name,
                                 'attendee_email': position.attendee_email,
+                                'company': position.company,
+                                'street': position.street,
+                                'zipcode': position.zipcode,
+                                'country': str(position.country) if position.country else None,
+                                'state': position.state,
                                 'secret': position.secret,
                                 'addon_to': position.addon_to_id,
                                 'answers': [
@@ -124,15 +177,30 @@ class JSONExporter(BaseExporter):
                             } for position in order.positions.all()
                         ]
                     } for order in
-                    self.event.orders.all().prefetch_related('positions', 'positions__answers', 'fees')
+                    self.event.orders.all().prefetch_related('positions', 'positions__answers', 'positions__seat', 'customer', 'fees')
                 ],
                 'quotas': [
                     {
                         'id': quota.id,
                         'size': quota.size,
+                        'subevent': quota.subevent_id,
                         'items': [item.id for item in quota.items.all()],
                         'variations': [variation.id for variation in quota.variations.all()],
                     } for quota in self.event.quotas.all().prefetch_related('items', 'variations')
+                ],
+                'subevents': [
+                    {
+                        'id': se.id,
+                        'name': str(se.name),
+                        'location': str(se.location),
+                        'date_from': se.date_from,
+                        'date_to': se.date_to,
+                        'date_admission': se.date_admission,
+                        'geo_lat': se.geo_lat,
+                        'geo_lon': se.geo_lon,
+                        'is_public': se.is_public,
+                        'meta_data': se.meta_data,
+                    } for se in self.event.subevents.all()
                 ]
             }
         }

src/pretix/base/exporters/orderlist.py

@@ -33,6 +33,7 @@
 # License for the specific language governing permissions and limitations under the License.
 
 from collections import OrderedDict
+from datetime import date, datetime, time
 from decimal import Decimal
 
 import dateutil
@@ -42,10 +43,10 @@ from django.db.models import (
     Case, CharField, Count, DateTimeField, F, IntegerField, Max, Min, OuterRef,
     Q, Subquery, Sum, When,
 )
-from django.db.models.functions import Coalesce, TruncDate
+from django.db.models.functions import Coalesce
 from django.dispatch import receiver
 from django.utils.functional import cached_property
-from django.utils.timezone import get_current_timezone, now
+from django.utils.timezone import get_current_timezone, make_aware, now
 from django.utils.translation import gettext as _, gettext_lazy, pgettext
 
 from pretix.base.models import (
@@ -181,41 +182,43 @@ class OrderListExporter(MultiSheetListExporter):
 
         if form_data.get('date_from'):
             date_value = form_data.get('date_from')
-            if isinstance(date_value, str):
+            if not isinstance(date_value, date):
                 date_value = dateutil.parser.parse(date_value).date()
+            datetime_value = make_aware(datetime.combine(date_value, time(0, 0, 0)), self.timezone)
 
-            annotations['date'] = TruncDate(f'{rel}datetime')
-            filters['date__gte'] = date_value
+            filters[f'{rel}datetime__gte'] = datetime_value
 
         if form_data.get('date_to'):
             date_value = form_data.get('date_to')
-            if isinstance(date_value, str):
+            if not isinstance(date_value, date):
                 date_value = dateutil.parser.parse(date_value).date()
+            datetime_value = make_aware(datetime.combine(date_value, time(23, 59, 59, 999999)), self.timezone)
 
-            annotations['date'] = TruncDate(f'{rel}datetime')
-            filters['date__lte'] = date_value
+            filters[f'{rel}datetime__lte'] = datetime_value
 
         if form_data.get('event_date_from'):
             date_value = form_data.get('event_date_from')
-            if isinstance(date_value, str):
+            if not isinstance(date_value, date):
                 date_value = dateutil.parser.parse(date_value).date()
+            datetime_value = make_aware(datetime.combine(date_value, time(0, 0, 0)), self.timezone)
 
             annotations['event_date_max'] = Case(
                 When(**{f'{rel}event__has_subevents': True}, then=Max(f'{rel}all_positions__subevent__date_from')),
                 default=F(f'{rel}event__date_from'),
             )
-            filters['event_date_max__gte'] = date_value
+            filters['event_date_max__gte'] = datetime_value
 
         if form_data.get('event_date_to'):
             date_value = form_data.get('event_date_to')
-            if isinstance(date_value, str):
+            if not isinstance(date_value, date):
                 date_value = dateutil.parser.parse(date_value).date()
+            datetime_value = make_aware(datetime.combine(date_value, time(23, 59, 59, 999999)), self.timezone)
 
             annotations['event_date_min'] = Case(
                 When(**{f'{rel}event__has_subevents': True}, then=Min(f'{rel}all_positions__subevent__date_from')),
                 default=F(f'{rel}event__date_from'),
             )
-            filters['event_date_min__lte'] = date_value
+            filters['event_date_min__lte'] = datetime_value
 
         if filters:
             return qs.annotate(**annotations).filter(**filters)
@@ -570,6 +573,7 @@ class OrderListExporter(MultiSheetListExporter):
             pgettext('address', 'State'),
             _('Voucher'),
             _('Pseudonymization ID'),
+            _('Ticket secret'),
             _('Seat ID'),
             _('Seat name'),
             _('Seat zone'),
@@ -666,6 +670,7 @@ class OrderListExporter(MultiSheetListExporter):
                     op.state or '',
                     op.voucher.code if op.voucher else '',
                     op.pseudonymization_id,
+                    op.secret,
                 ]
 
                 if op.seat:
@@ -870,6 +875,78 @@ class QuotaListExporter(ListExporter):
         return '{}_quotas'.format(self.event.slug)
 
 
+def generate_GiftCardTransactionListExporter(organizer):  # hackhack
+    class GiftcardTransactionListExporter(ListExporter):
+        identifier = 'giftcardtransactionlist'
+        verbose_name = gettext_lazy('Gift card transactions')
+
+        @property
+        def additional_form_fields(self):
+            d = [
+                ('date_from',
+                 forms.DateField(
+                     label=_('Start date'),
+                     widget=forms.DateInput(attrs={'class': 'datepickerfield'}),
+                     required=False,
+                 )),
+                ('date_to',
+                 forms.DateField(
+                     label=_('End date'),
+                     widget=forms.DateInput(attrs={'class': 'datepickerfield'}),
+                     required=False,
+                 )),
+            ]
+            d = OrderedDict(d)
+            return d
+
+        def iterate_list(self, form_data):
+            qs = GiftCardTransaction.objects.filter(
+                card__issuer=organizer,
+            ).order_by('datetime').select_related('card', 'order', 'order__event')
+
+            if form_data.get('date_from'):
+                date_value = form_data.get('date_from')
+                if isinstance(date_value, str):
+                    date_value = dateutil.parser.parse(date_value).date()
+                qs = qs.filter(
+                    datetime__gte=make_aware(datetime.combine(date_value, time(0, 0, 0)), self.timezone)
+                )
+
+            if form_data.get('date_to'):
+                date_value = form_data.get('date_to')
+                if isinstance(date_value, str):
+                    date_value = dateutil.parser.parse(date_value).date()
+
+                qs = qs.filter(
+                    datetime__lte=make_aware(datetime.combine(date_value, time(23, 59, 59, 999999)), self.timezone)
+                )
+
+            headers = [
+                _('Gift card code'),
+                _('Test mode'),
+                _('Date'),
+                _('Amount'),
+                _('Currency'),
+                _('Order'),
+            ]
+            yield headers
+
+            for obj in qs:
+                row = [
+                    obj.card.secret,
+                    _('TEST MODE') if obj.card.testmode else '',
+                    obj.datetime.astimezone(self.timezone).strftime('%Y-%m-%d %H:%M:%S'),
+                    obj.value,
+                    obj.card.currency,
+                    obj.order.full_code if obj.order else None,
+                ]
+                yield row
+
+        def get_filename(self):
+            return '{}_giftcardtransactions'.format(organizer.slug)
+    return GiftcardTransactionListExporter
+
+
 class GiftcardRedemptionListExporter(ListExporter):
     identifier = 'giftcardredemptionlist'
     verbose_name = gettext_lazy('Gift card redemptions')
@@ -1062,3 +1139,8 @@ def register_multievent_i_giftcardredemptionlist_exporter(sender, **kwargs):
 @receiver(register_multievent_data_exporters, dispatch_uid="multiexporter_giftcardlist")
 def register_multievent_i_giftcardlist_exporter(sender, **kwargs):
     return generate_GiftCardListExporter(sender)
+
+
+@receiver(register_multievent_data_exporters, dispatch_uid="multiexporter_giftcardtransactionlist")
+def register_multievent_i_giftcardtransactionlist_exporter(sender, **kwargs):
+    return generate_GiftCardTransactionListExporter(sender)

src/pretix/base/forms/__init__.py

@@ -38,6 +38,7 @@ import i18nfield.forms
 from django import forms
 from django.forms.models import ModelFormMetaclass
 from django.utils.crypto import get_random_string
+from django.utils.translation import gettext_lazy as _
 from formtools.wizard.views import SessionWizardView
 from hierarkey.forms import HierarkeyForm
 
@@ -118,6 +119,33 @@ class SettingsForm(i18nfield.forms.I18nFormMixin, HierarkeyForm):
                 self.cleaned_data[k] = self.initial[k]
         return super().save()
 
+    def clean(self):
+        d = super().clean()
+
+        # There is logic in HierarkeyForm.save() to only persist fields that changed. HierarkeyForm determines if
+        # something changed by comparing `self._s.get(name)` to `value`. This leaves an edge case open for multi-lingual
+        # text fields. On the very first load, the initial value in `self._s.get(name)` will be a LazyGettextProxy-based
+        # string. However, only some of the languages are usually visible, so even if the user does not change anything
+        # at all, it will be considered a changed value and stored. We do not want that, as it makes it very hard to add
+        # languages to an organizer/event later on. So we trick it and make sure nothing gets changed in that situation.
+        for name, field in self.fields.items():
+            if isinstance(field, SecretKeySettingsField) and d.get(name) == SECRET_REDACTED and not self.initial.get(name):
+                self.add_error(
+                    name,
+                    _('Due to technical reasons you cannot set inputs, that need to be masked (e.g. passwords), to %(value)s.') % {'value': SECRET_REDACTED}
+                )
+
+            if isinstance(field, i18nfield.forms.I18nFormField):
+                value = d.get(name)
+                if not value:
+                    continue
+
+                current = self._s.get(name, as_type=type(value))
+                if name not in self.changed_data:
+                    d[name] = current
+
+        return d
+
     def get_new_filename(self, name: str) -> str:
         from pretix.base.models import Event
 

src/pretix/base/forms/auth.py

@@ -154,6 +154,7 @@ class RegistrationForm(forms.Form):
         widget=forms.PasswordInput(attrs={
             'autocomplete': 'new-password'  # see https://bugs.chromium.org/p/chromium/issues/detail?id=370363#c7
         }),
+        max_length=4096,
         required=True
     )
     password_repeat = forms.CharField(
@@ -161,6 +162,7 @@ class RegistrationForm(forms.Form):
         widget=forms.PasswordInput(attrs={
             'autocomplete': 'new-password'  # see https://bugs.chromium.org/p/chromium/issues/detail?id=370363#c7
         }),
+        max_length=4096,
         required=True
     )
     keep_logged_in = forms.BooleanField(label=_("Keep me logged in"), required=False)
@@ -204,11 +206,13 @@ class PasswordRecoverForm(forms.Form):
     password = forms.CharField(
         label=_('Password'),
         widget=forms.PasswordInput,
+        max_length=4096,
         required=True
     )
     password_repeat = forms.CharField(
         label=_('Repeat password'),
-        widget=forms.PasswordInput
+        widget=forms.PasswordInput,
+        max_length=4096,
     )
 
     def __init__(self, user_id=None, *args, **kwargs):

src/pretix/base/forms/questions.py

@@ -37,22 +37,21 @@ import json
 import logging
 from decimal import Decimal
 from io import BytesIO
-from urllib.error import HTTPError
 
 import dateutil.parser
 import pycountry
 import pytz
-import vat_moss.errors
-import vat_moss.id
 from babel import Locale
 from django import forms
 from django.conf import settings
 from django.contrib import messages
 from django.core.exceptions import ValidationError
 from django.core.files.uploadedfile import SimpleUploadedFile
-from django.core.validators import MaxValueValidator, MinValueValidator
+from django.core.validators import (
+    MaxValueValidator, MinValueValidator, RegexValidator,
+)
 from django.db.models import QuerySet
-from django.forms import Select
+from django.forms import Select, widgets
 from django.utils import translation
 from django.utils.formats import date_format
 from django.utils.html import escape
@@ -76,8 +75,9 @@ from pretix.base.i18n import (
     get_babel_locale, get_language_without_region, language,
 )
 from pretix.base.models import InvoiceAddress, Question, QuestionOption
-from pretix.base.models.tax import (
-    EU_COUNTRIES, cc_to_vat_prefix, is_eu_country,
+from pretix.base.models.tax import VAT_ID_COUNTRIES, ask_for_vat_id
+from pretix.base.services.tax import (
+    VATIDFinalError, VATIDTemporaryError, validate_vat_id,
 )
 from pretix.base.settings import (
     COUNTRIES_WITH_STATE_IN_ADDRESS, PERSON_NAME_SALUTATIONS,
@@ -154,8 +154,9 @@ class NamePartsWidget(forms.MultiWidget):
                     final_attrs,
                     id='%s_%s' % (id_, i),
                     title=self.scheme['fields'][i][1],
-                    placeholder=self.scheme['fields'][i][1],
                 )
+                if not isinstance(widget, widgets.Select):
+                    these_attrs['placeholder'] = self.scheme['fields'][i][1]
                 if self.scheme['fields'][i][0] in REQUIRED_NAME_PARTS:
                     if self.field.required:
                         these_attrs['required'] = 'required'
@@ -188,6 +189,15 @@ class NamePartsFormField(forms.MultiValueField):
         defaults = {
             'widget': self.widget,
             'max_length': kwargs.pop('max_length', None),
+            'validators': [
+                RegexValidator(
+                    # The following characters should never appear in a name anywhere of
+                    # the world. However, they commonly appear in inputs generated by spam
+                    # bots.
+                    r'^[^$€/%§{}<>~]*$',
+                    message=_('Please do not use special characters in names.')
+                )
+            ]
         }
         self.scheme_name = kwargs.pop('scheme')
         self.titles = kwargs.pop('titles')
@@ -208,6 +218,7 @@ class NamePartsFormField(forms.MultiValueField):
             if fname == 'title' and self.scheme_titles:
                 d = dict(defaults)
                 d.pop('max_length', None)
+                d.pop('validators', None)
                 field = forms.ChoiceField(
                     **d,
                     choices=[('', '')] + [(d, d) for d in self.scheme_titles[1]]
@@ -216,6 +227,7 @@ class NamePartsFormField(forms.MultiValueField):
             elif fname == 'salutation':
                 d = dict(defaults)
                 d.pop('max_length', None)
+                d.pop('validators', None)
                 field = forms.ChoiceField(
                     **d,
                     choices=[('', '---')] + PERSON_NAME_SALUTATIONS
@@ -334,23 +346,41 @@ class WrappedPhoneNumberPrefixWidget(PhoneNumberPrefixWidget):
 def guess_country(event):
     # Try to guess the initial country from either the country of the merchant
     # or the locale. This will hopefully save at least some users some scrolling :)
-    locale = get_language_without_region()
     country = event.settings.region or event.settings.invoice_address_from_country
     if not country:
-        valid_countries = countries.countries
-        if '-' in locale:
-            parts = locale.split('-')
-            # TODO: does this actually work?
-            if parts[1].upper() in valid_countries:
-                country = Country(parts[1].upper())
-            elif parts[0].upper() in valid_countries:
-                country = Country(parts[0].upper())
-        else:
-            if locale.upper() in valid_countries:
-                country = Country(locale.upper())
+        country = get_country_by_locale(get_language_without_region())
     return country
 
 
+def get_country_by_locale(locale):
+    country = None
+    valid_countries = countries.countries
+    if '-' in locale:
+        parts = locale.split('-')
+        # TODO: does this actually work?
+        if parts[1].upper() in valid_countries:
+            country = Country(parts[1].upper())
+        elif parts[0].upper() in valid_countries:
+            country = Country(parts[0].upper())
+    else:
+        if locale.upper() in valid_countries:
+            country = Country(locale.upper())
+    return country
+
+
+def guess_phone_prefix(event):
+    with language(get_babel_locale()):
+        country = str(guess_country(event))
+        return get_phone_prefix(country)
+
+
+def get_phone_prefix(country):
+    for prefix, values in _COUNTRY_CODE_TO_REGION_CODE.items():
+        if country in values:
+            return prefix
+    return None
+
+
 class QuestionCheckboxSelectMultiple(forms.CheckboxSelectMultiple):
     option_template_name = 'pretixbase/forms/widgets/checkbox_option_with_links.html'
 
@@ -781,25 +811,26 @@ class BaseQuestionsForm(forms.Form):
                 if q.valid_datetime_max:
                     field.validators.append(MaxDateTimeValidator(q.valid_datetime_max))
             elif q.type == Question.TYPE_PHONENUMBER:
-                with language(get_babel_locale()):
-                    default_country = guess_country(event)
-                    default_prefix = None
-                    for prefix, values in _COUNTRY_CODE_TO_REGION_CODE.items():
-                        if str(default_country) in values:
-                            default_prefix = prefix
+                if initial:
                     try:
-                        initial = PhoneNumber().from_string(initial.answer) if initial else "+{}.".format(default_prefix)
+                        initial = PhoneNumber().from_string(initial.answer)
                     except NumberParseException:
                         initial = None
-                    field = PhoneNumberField(
-                        label=label, required=required,
-                        help_text=help_text,
-                        # We now exploit an implementation detail in PhoneNumberPrefixWidget to allow us to pass just
-                        # a country code but no number as an initial value. It's a bit hacky, but should be stable for
-                        # the future.
-                        initial=initial,
-                        widget=WrappedPhoneNumberPrefixWidget()
-                    )
+
+                if not initial:
+                    phone_prefix = guess_phone_prefix(event)
+                    if phone_prefix:
+                        initial = "+{}.".format(phone_prefix)
+
+                field = PhoneNumberField(
+                    label=label, required=required,
+                    help_text=help_text,
+                    # We now exploit an implementation detail in PhoneNumberPrefixWidget to allow us to pass just
+                    # a country code but no number as an initial value. It's a bit hacky, but should be stable for
+                    # the future.
+                    initial=initial,
+                    widget=WrappedPhoneNumberPrefixWidget()
+                )
             field.question = q
             if answers:
                 # Cache the answer object for later use
@@ -870,6 +901,12 @@ class BaseQuestionsForm(forms.Form):
                 if question_is_required(q) and not answer and answer != 0 and not field.errors:
                     raise ValidationError({'question_%d' % q.pk: [_('This field is required.')]})
 
+        # Strip invisible question from cleaned_data so they don't end up in the database
+        for q in question_cache.values():
+            answer = d.get('question_%d' % q.pk)
+            if q.dependency_question_id and not question_is_visible(q.dependency_question_id, q.dependency_values) and answer is not None:
+                d['question_%d' % q.pk] = None
+
         return d
 
 
@@ -901,7 +938,7 @@ class BaseInvoiceAddressForm(forms.ModelForm):
                 'data-display-dependency': '#id_is_business_1',
                 'autocomplete': 'organization',
             }),
-            'vat_id': forms.TextInput(attrs={'data-display-dependency': '#id_is_business_1', 'data-countries-in-eu': ','.join(EU_COUNTRIES)}),
+            'vat_id': forms.TextInput(attrs={'data-display-dependency': '#id_is_business_1', 'data-countries-with-vat-id': ','.join(VAT_ID_COUNTRIES)}),
             'internal_reference': forms.TextInput,
         }
         labels = {
@@ -921,6 +958,18 @@ class BaseInvoiceAddressForm(forms.ModelForm):
         super().__init__(*args, **kwargs)
         if not event.settings.invoice_address_vatid:
             del self.fields['vat_id']
+        elif self.validate_vat_id:
+            self.fields['vat_id'].help_text = '<br/>'.join([
+                str(_('Optional, but depending on the country you reside in we might need to charge you '
+                      'additional taxes if you do not enter it.')),
+                str(_('If you are registered in Switzerland, you can enter your UID instead.')),
+            ])
+        else:
+            self.fields['vat_id'].help_text = '<br/>'.join([
+                str(_('Optional, but it might be required for you to claim tax benefits on your invoice '
+                      'depending on your and the seller’s country of residence.')),
+                str(_('If you are registered in Switzerland, you can enter your UID instead.')),
+            ])
 
         self.fields['country'].choices = CachedCountries()
 
@@ -952,7 +1001,7 @@ class BaseInvoiceAddressForm(forms.ModelForm):
         self.fields['state'].widget.is_required = True
 
         # Without JavaScript the VAT ID field is not hidden, so we empty the field if a country outside the EU is selected.
-        if cc and not is_eu_country(cc) and fprefix + 'vat_id' in self.data:
+        if cc and not ask_for_vat_id(cc) and fprefix + 'vat_id' in self.data:
             self.data = self.data.copy()
             del self.data[fprefix + 'vat_id']
 
@@ -1002,7 +1051,7 @@ class BaseInvoiceAddressForm(forms.ModelForm):
         if not data.get('is_business'):
             data['company'] = ''
             data['vat_id'] = ''
-        if data.get('is_business') and not is_eu_country(data.get('country')):
+        if data.get('is_business') and not ask_for_vat_id(data.get('country')):
             data['vat_id'] = ''
         if self.event.settings.invoice_address_required:
             if data.get('is_business') and not data.get('company'):
@@ -1025,36 +1074,23 @@ class BaseInvoiceAddressForm(forms.ModelForm):
             # Do not save the country if it is the only field set -- we don't know the user even checked it!
             self.cleaned_data['country'] = ''
 
-        if data.get('vat_id') and is_eu_country(data.get('country')) and data.get('vat_id')[:2] != cc_to_vat_prefix(str(data.get('country'))):
-            raise ValidationError(_('Your VAT ID does not match the selected country.'))
-
         if self.validate_vat_id and self.instance.vat_id_validated and 'vat_id' not in self.changed_data:
             pass
-        elif self.validate_vat_id and data.get('is_business') and is_eu_country(data.get('country')) and data.get('vat_id'):
+        elif self.validate_vat_id and data.get('is_business') and ask_for_vat_id(data.get('country')) and data.get('vat_id'):
             try:
-                result = vat_moss.id.validate(data.get('vat_id'))
-                if result:
-                    country_code, normalized_id, company_name = result
-                    self.instance.vat_id_validated = True
-                    self.instance.vat_id = normalized_id
-            except (vat_moss.errors.InvalidError, ValueError):
-                raise ValidationError(_('This VAT ID is not valid. Please re-check your input.'))
-            except vat_moss.errors.WebServiceUnavailableError:
-                logger.exception('VAT ID checking failed for country {}'.format(data.get('country')))
+                normalized_id = validate_vat_id(data.get('vat_id'), str(data.get('country')))
+                self.instance.vat_id_validated = True
+                self.instance.vat_id = normalized_id
+            except VATIDFinalError as e:
+                if self.all_optional:
+                    self.instance.vat_id_validated = False
+                    messages.warning(self.request, e.message)
+                else:
+                    raise ValidationError(e.message)
+            except VATIDTemporaryError as e:
                 self.instance.vat_id_validated = False
                 if self.request and self.vat_warning:
-                    messages.warning(self.request, _('Your VAT ID could not be checked, as the VAT checking service of '
-                                                     'your country is currently not available. We will therefore '
-                                                     'need to charge VAT on your invoice. You can get the tax amount '
-                                                     'back via the VAT reimbursement process.'))
-            except (vat_moss.errors.WebServiceError, HTTPError):
-                logger.exception('VAT ID checking failed for country {}'.format(data.get('country')))
-                self.instance.vat_id_validated = False
-                if self.request and self.vat_warning:
-                    messages.warning(self.request, _('Your VAT ID could not be checked, as the VAT checking service of '
-                                                     'your country returned an incorrect result. We will therefore '
-                                                     'need to charge VAT on your invoice. Please contact support to '
-                                                     'resolve this manually.'))
+                    messages.warning(self.request, e.message)
         else:
             self.instance.vat_id_validated = False
 

src/pretix/base/forms/user.py

@@ -55,6 +55,7 @@ class UserSettingsForm(forms.ModelForm):
         'pw_current_wrong': _("The current password you entered was not correct."),
         'pw_mismatch': _("Please enter the same password twice"),
         'rate_limit': _("For security reasons, please wait 5 minutes before you try again."),
+        'pw_equal': _("Please choose a password different to your current one.")
     }
 
     old_pw = forms.CharField(max_length=255,
@@ -158,6 +159,12 @@ class UserSettingsForm(forms.ModelForm):
                 code='pw_current'
             )
 
+        if password1 and password1 == old_pw:
+            raise forms.ValidationError(
+                self.error_messages['pw_equal'],
+                code='pw_equal'
+            )
+
         if password1:
             self.instance.set_password(password1)
 

src/pretix/base/forms/widgets.py

@@ -86,14 +86,6 @@ class TimePickerWidget(forms.TimeInput):
 
 class UploadedFileWidget(forms.ClearableFileInput):
     def __init__(self, *args, **kwargs):
-        # Browsers can't recognize that the server already has a file uploaded
-        # Don't mark this input as being required if we already have an answer
-        # (this needs to be done via the attrs, otherwise we wouldn't get the "required" star on the field label)
-        attrs = kwargs.get('attrs', {})
-        if kwargs.get('required') and kwargs.get('initial'):
-            attrs.update({'required': None})
-        kwargs.update({'attrs': attrs})
-
         self.position = kwargs.pop('position')
         self.event = kwargs.pop('event')
         self.answer = kwargs.pop('answer')
@@ -125,6 +117,15 @@ class UploadedFileWidget(forms.ClearableFileInput):
                     'answer': self.answer.pk,
                 })
 
+    def get_context(self, name, value, attrs):
+        # Browsers can't recognize that the server already has a file uploaded
+        # Don't mark this input as being required if we already have an answer
+        # (this needs to be done via the attrs, otherwise we wouldn't get the "required" star on the field label)
+        ctx = super().get_context(name, value, attrs)
+        if ctx['widget']['is_initial']:
+            ctx['widget']['attrs']['required'] = False
+        return ctx
+
     def format_value(self, value):
         if self.is_initial(value):
             return self.FakeFile(value, self.position, self.event, self.answer)

src/pretix/base/invoice.py

@@ -395,7 +395,13 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
             return txt
 
         if not self.invoice.event.has_subevents and self.invoice.event.settings.show_dates_on_frontpage:
-            if self.invoice.event.settings.show_date_to and self.invoice.event.date_to:
+            tz = self.invoice.event.timezone
+            show_end_date = (
+                self.invoice.event.settings.show_date_to and
+                self.invoice.event.date_to and
+                self.invoice.event.date_to.astimezone(tz).date() != self.invoice.event.date_from.astimezone(tz).date()
+            )
+            if show_end_date:
                 p_str = (
                     shorten(self.invoice.event.name) + '\n' +
                     pgettext('invoice', '{from_date}\nuntil {to_date}').format(
@@ -550,7 +556,10 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
         for line in self.invoice.lines.all():
             if has_taxes:
                 tdata.append((
-                    Paragraph(line.description, self.stylesheet['Normal']),
+                    Paragraph(
+                        bleach.clean(line.description, tags=['br']).strip().replace('<br>', '<br/>').replace('\n', '<br />\n'),
+                        self.stylesheet['Normal']
+                    ),
                     "1",
                     localize(line.tax_rate) + " %",
                     money_filter(line.net_value, self.invoice.event.currency),
@@ -558,7 +567,10 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
                 ))
             else:
                 tdata.append((
-                    Paragraph(line.description, self.stylesheet['Normal']),
+                    Paragraph(
+                        bleach.clean(line.description, tags=['br']).strip().replace('<br>', '<br/>').replace('\n', '<br />\n'),
+                        self.stylesheet['Normal']
+                    ),
                     "1",
                     money_filter(line.gross_value, self.invoice.event.currency),
                 ))
@@ -595,7 +607,7 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
         table.setStyle(TableStyle(tstyledata))
         story.append(table)
 
-        story.append(Spacer(1, 15 * mm))
+        story.append(Spacer(1, 10 * mm))
 
         if self.invoice.payment_provider_text:
             story.append(Paragraph(
@@ -611,12 +623,14 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
                 self.invoice.additional_text,
                 self.stylesheet['Normal']
             ))
-            story.append(Spacer(1, 15 * mm))
+            story.append(Spacer(1, 5 * mm))
 
         tstyledata = [
             ('ALIGN', (1, 0), (-1, -1), 'RIGHT'),
             ('LEFTPADDING', (0, 0), (0, -1), 0),
             ('RIGHTPADDING', (-1, 0), (-1, -1), 0),
+            ('TOPPADDING', (0, 0), (-1, -1), 1),
+            ('BOTTOMPADDING', (0, 0), (-1, -1), 1),
             ('FONTSIZE', (0, 0), (-1, -1), 8),
             ('FONTNAME', (0, 0), (-1, -1), self.font_regular),
         ]

src/pretix/base/management/commands/check_order_transactions.py

@@ -0,0 +1,107 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+from decimal import Decimal
+
+from django.core.management.base import BaseCommand
+from django.db import models
+from django.db.models import (
+    Case, Count, F, OuterRef, Q, Subquery, Sum, Value, When,
+)
+from django.db.models.functions import Coalesce
+from django_scopes import scopes_disabled
+
+from pretix.base.models import Order, OrderFee, OrderPosition
+from pretix.base.models.orders import Transaction
+
+
+class Command(BaseCommand):
+    help = "Check order for consistency with their transactions"
+
+    @scopes_disabled()
+    def handle(self, *args, **options):
+        qs = Order.objects.annotate(
+            position_total=Coalesce(
+                Subquery(
+                    OrderPosition.objects.filter(
+                        order=OuterRef('pk')
+                    ).order_by().values('order').annotate(p=Sum('price')).values('p'),
+                    output_field=models.DecimalField(decimal_places=2, max_digits=10)
+                ), Value(0), output_field=models.DecimalField(decimal_places=2, max_digits=10)
+            ),
+            position_cnt=Case(
+                When(Q(status__in=('e', 'c')) | Q(require_approval=True), then=Value(0)),
+                default=Coalesce(
+                    Subquery(
+                        OrderPosition.objects.filter(
+                            order=OuterRef('pk')
+                        ).order_by().values('order').annotate(p=Count('*')).values('p'),
+                        output_field=models.IntegerField()
+                    ), Value(0), output_field=models.IntegerField()
+                ),
+                output_field=models.IntegerField()
+            ),
+            fee_total=Coalesce(
+                Subquery(
+                    OrderFee.objects.filter(
+                        order=OuterRef('pk')
+                    ).order_by().values('order').annotate(p=Sum('value')).values('p'),
+                    output_field=models.DecimalField(decimal_places=2, max_digits=10)
+                ), Value(0), output_field=models.DecimalField(decimal_places=2, max_digits=10)
+            ),
+            tx_total=Coalesce(
+                Subquery(
+                    Transaction.objects.filter(
+                        order=OuterRef('pk')
+                    ).order_by().values('order').annotate(p=Sum(F('price') * F('count'))).values('p'),
+                    output_field=models.DecimalField(decimal_places=2, max_digits=10)
+                ), Value(0), output_field=models.DecimalField(decimal_places=2, max_digits=10)
+            ),
+            tx_cnt=Coalesce(
+                Subquery(
+                    Transaction.objects.filter(
+                        order=OuterRef('pk'),
+                        item__isnull=False,
+                    ).order_by().values('order').annotate(p=Sum(F('count'))).values('p'),
+                    output_field=models.DecimalField(decimal_places=2, max_digits=10)
+                ), Value(0), output_field=models.DecimalField(decimal_places=2, max_digits=10)
+            ),
+        ).annotate(
+            correct_total=Case(
+                When(Q(status=Order.STATUS_CANCELED) | Q(status=Order.STATUS_EXPIRED) | Q(require_approval=True),
+                     then=Value(0)),
+                default=F('position_total') + F('fee_total'),
+                output_field=models.DecimalField(decimal_places=2, max_digits=10)
+            ),
+        ).exclude(
+            total=F('position_total') + F('fee_total'),
+            tx_total=F('correct_total'),
+            tx_cnt=F('position_cnt')
+        ).select_related('event')
+        for o in qs:
+            if abs(o.tx_total - o.correct_total) < Decimal('0.00001') and abs(o.position_total + o.fee_total - o.total) < Decimal('0.00001') \
+                    and o.tx_cnt == o.position_cnt:
+                # Ignore SQLite which treats Decimals like floats…
+                continue
+            print(f"Error in order {o.full_code}: status={o.status}, sum(positions)+sum(fees)={o.position_total + o.fee_total}, "
+                  f"order.total={o.total}, sum(transactions)={o.tx_total}, expected={o.correct_total}, pos_cnt={o.position_cnt}, tx_pos_cnt={o.tx_cnt}")
+
+        self.stderr.write(self.style.SUCCESS('Check completed.'))

src/pretix/base/management/commands/create_order_transactions.py

@@ -0,0 +1,95 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+import time
+
+from django.core.management.base import BaseCommand
+from django.db.models import F, Max, Q
+from django.utils.timezone import now
+from django_scopes import scopes_disabled
+from tqdm import tqdm
+
+from pretix.base.models import Order
+
+
+class Command(BaseCommand):
+    help = "Create missing order transactions"
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "--slowdown",
+            dest="interval",
+            type=int,
+            default=0,
+            help="Interval for staggered execution. If set to a value different then zero, we will "
+                 "wait this many milliseconds between every order we process.",
+        )
+
+    @scopes_disabled()
+    def handle(self, *args, **options):
+        t = 0
+        qs = Order.objects.annotate(
+            last_transaction=Max('transactions__created')
+        ).filter(
+            Q(last_transaction__isnull=True) | Q(last_modified__gt=F('last_transaction')),
+            require_approval=False,
+        ).prefetch_related(
+            'all_positions', 'all_fees'
+        ).order_by(
+            'pk'
+        )
+        last_pk = 0
+        with tqdm(total=qs.count()) as pbar:
+            while True:
+                batch = list(qs.filter(pk__gt=last_pk)[:5000])
+                if not batch:
+                    break
+
+                for o in batch:
+                    if o.last_transaction is None:
+                        tn = o.create_transactions(
+                            positions=o.all_positions.all(),
+                            fees=o.all_fees.all(),
+                            dt_now=o.datetime,
+                            migrated=True,
+                            is_new=True,
+                            _backfill_before_cancellation=True,
+                        )
+                        o.create_transactions(
+                            positions=o.all_positions.all(),
+                            fees=o.all_fees.all(),
+                            dt_now=o.cancellation_date or (o.expires if o.status == Order.STATUS_EXPIRED else o.datetime),
+                            migrated=True,
+                        )
+                    else:
+                        tn = o.create_transactions(
+                            positions=o.all_positions.all(),
+                            fees=o.all_fees.all(),
+                            dt_now=now(),
+                            migrated=True,
+                        )
+                    if tn:
+                        t += 1
+                    time.sleep(0)
+                    pbar.update(1)
+                last_pk = batch[-1].pk
+
+        self.stderr.write(self.style.SUCCESS(f'Created transactions for {t} orders.'))

src/pretix/base/middleware.py

@@ -208,7 +208,7 @@ def _parse_csp(header):
 
 
 def _render_csp(h):
-    return "; ".join(k + ' ' + ' '.join(v) for k, v in h.items())
+    return "; ".join(k + ' ' + ' '.join(v) for k, v in h.items() if v)
 
 
 def _merge_csp(a, b):

src/pretix/base/migrations/0198_invoice_sent_to_customer.py

@@ -0,0 +1,21 @@
+# Generated by Django 3.2.4 on 2021-09-30 10:25
+from datetime import datetime
+
+from django.db import migrations, models
+from pytz import UTC
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0197_auto_20210914_0814'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='invoice',
+            name='sent_to_customer',
+            field=models.DateTimeField(blank=True, null=True, default=UTC.localize(datetime(1970, 1, 1, 0, 0, 0, 0))),
+            preserve_default=False,
+        ),
+    ]

src/pretix/base/migrations/0199_auto_20211005_1050.py

@@ -0,0 +1,23 @@
+# Generated by Django 3.2.4 on 2021-10-05 10:50
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0198_invoice_sent_to_customer'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='item',
+            name='require_membership_hidden',
+            field=models.BooleanField(default=False),
+        ),
+        migrations.AddField(
+            model_name='itemvariation',
+            name='require_membership_hidden',
+            field=models.BooleanField(default=False),
+        ),
+    ]

src/pretix/base/migrations/0200_transaction.py

@@ -0,0 +1,38 @@
+# Generated by Django 3.2.4 on 2021-10-18 10:27
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0199_auto_20211005_1050'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Transaction',
+            fields=[
+                ('id', models.BigAutoField(primary_key=True, serialize=False)),
+                ('created', models.DateTimeField(auto_now_add=True, db_index=True)),
+                ('datetime', models.DateTimeField(db_index=True)),
+                ('migrated', models.BooleanField(default=False)),
+                ('positionid', models.PositiveIntegerField(default=1, null=True)),
+                ('count', models.IntegerField(default=1)),
+                ('price', models.DecimalField(decimal_places=2, max_digits=10)),
+                ('tax_rate', models.DecimalField(decimal_places=2, max_digits=7)),
+                ('tax_value', models.DecimalField(decimal_places=2, max_digits=10)),
+                ('fee_type', models.CharField(max_length=100, null=True)),
+                ('internal_type', models.CharField(max_length=255, null=True)),
+                ('item', models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to='pretixbase.item')),
+                ('order', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='transactions', to='pretixbase.order')),
+                ('subevent', models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to='pretixbase.subevent')),
+                ('tax_rule', models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to='pretixbase.taxrule')),
+                ('variation', models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, to='pretixbase.itemvariation')),
+            ],
+            options={
+                'ordering': ('datetime', 'pk'),
+            },
+        ),
+    ]

src/pretix/base/migrations/0201_invoiceline_event_location.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.4 on 2021-11-03 09:24
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0200_transaction'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='invoiceline',
+            name='event_location',
+            field=models.TextField(null=True),
+        ),
+    ]

src/pretix/base/migrations/0202_user_needs_password_change.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.9 on 2021-11-04 13:05
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0201_invoiceline_event_location'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='user',
+            name='needs_password_change',
+            field=models.BooleanField(default=False),
+        ),
+    ]

src/pretix/base/migrations/0203_orderposition_is_bundled.py

@@ -0,0 +1,17 @@
+# Generated by Django 3.2.2 on 2021-11-08 07:51
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('pretixbase', '0202_user_needs_password_change'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='orderposition',
+            name='is_bundled',
+            field=models.BooleanField(default=False),
+        ),
+    ]

src/pretix/base/migrations/0204_orderposition_backfill_is_bundled.py

@@ -0,0 +1,46 @@
+# Generated by Django 3.2.2 on 2021-11-08 07:51
+
+from django.db import migrations, models
+from django.db.models import Count, OuterRef, Subquery
+from django.db.models.functions import Coalesce
+
+
+def fill_is_bundled(apps, schema_editor):
+    # We cannot really know if a position was bundled or an add-on, but we can at least guess
+    ItemBundle = apps.get_model("pretixbase", "ItemBundle")
+    OrderPosition = apps.get_model("pretixbase", "OrderPosition")
+
+    for ib in ItemBundle.objects.iterator():
+        OrderPosition.all.alias(
+            pos_earlier=Coalesce(Subquery(
+                OrderPosition.all.filter(
+                    canceled=False,
+                    addon_to=OuterRef('addon_to'),
+                    item=ib.bundled_item,
+                    variation=ib.bundled_variation,
+                    positionid__lt=OuterRef('positionid'),
+                ).values('addon_to').order_by().annotate(c=Count('*')).values('c'),
+                output_field=models.IntegerField()
+            ), 0)
+        ).filter(
+            canceled=False,
+            addon_to__item=ib.base_item,
+            item=ib.bundled_item,
+            variation=ib.bundled_variation,
+            pos_earlier__lt=ib.count,
+        ).update(
+            is_bundled=True
+        )
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ('pretixbase', '0203_orderposition_is_bundled'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            fill_is_bundled,
+            migrations.RunPython.noop,
+        ),
+    ]

src/pretix/base/migrations/0205_itemvariation_require_approval.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.9 on 2021-12-13 14:21
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0204_orderposition_backfill_is_bundled'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='itemvariation',
+            name='require_approval',
+            field=models.BooleanField(default=False),
+        ),
+    ]

src/pretix/base/migrations/0206_customer_phone.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.2.9 on 2022-01-12 10:59
+
+import phonenumber_field.modelfields
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0205_itemvariation_require_approval'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='customer',
+            name='phone',
+            field=phonenumber_field.modelfields.PhoneNumberField(max_length=128, null=True, region=None),
+        ),
+    ]

src/pretix/base/migrations/0207_auto_20220119_1427.py

@@ -0,0 +1,23 @@
+# Generated by Django 3.2.4 on 2022-01-19 14:27
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0206_customer_phone'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='taxrule',
+            name='internal_name',
+            field=models.CharField(max_length=190, null=True),
+        ),
+        migrations.AddField(
+            model_name='taxrule',
+            name='keep_gross_if_rate_changes',
+            field=models.BooleanField(default=False),
+        ),
+    ]

src/pretix/base/migrations/0208_auto_20220214_1632.py

@@ -0,0 +1,22 @@
+# Generated by Django 3.2.4 on 2022-02-14 16:32
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0207_auto_20220119_1427'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='user',
+            name='auth_backend_identifier',
+            field=models.CharField(db_index=True, max_length=190, null=True),
+        ),
+        migrations.AlterUniqueTogether(
+            name='user',
+            unique_together={('auth_backend', 'auth_backend_identifier')},
+        ),
+    ]

src/pretix/base/models/__init__.py

@@ -42,8 +42,9 @@ from .notifications import NotificationSetting
 from .orders import (
     AbstractPosition, CachedCombinedTicket, CachedTicket, CartPosition,
     InvoiceAddress, Order, OrderFee, OrderPayment, OrderPosition, OrderRefund,
-    QuestionAnswer, RevokedTicketSecret, cachedcombinedticket_name,
-    cachedticket_name, generate_position_secret, generate_secret,
+    QuestionAnswer, RevokedTicketSecret, Transaction,
+    cachedcombinedticket_name, cachedticket_name, generate_position_secret,
+    generate_secret,
 )
 from .organizer import (
     Organizer, Organizer_SettingsStore, Team, TeamAPIToken, TeamInvite,

src/pretix/base/models/_transactions.py

@@ -0,0 +1,113 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+
+"""
+This module contains helper functions that are supposed to call out code paths missing calls to
+``Order.create_transaction()`` by actively breaking them. Read the docstring of the ``Transaction`` class for a
+detailed reasoning why this exists.
+"""
+import inspect
+import logging
+import os
+import threading
+
+from django.conf import settings
+from django.db import transaction
+
+dirty_transactions = threading.local()
+
+logger = logging.getLogger(__name__)
+fail_loudly = os.getenv('PRETIX_DIRTY_TRANSACTIONS_QUIET', 'false' if settings.DEBUG else 'true') not in ('true', 'True', 'on', '1')
+
+
+class DirtyTransactionsForOrderException(Exception):
+    pass
+
+
+def _fail(message):
+    if fail_loudly:
+        raise DirtyTransactionsForOrderException(message)
+    else:
+        if settings.SENTRY_ENABLED:
+            import sentry_sdk
+
+            sentry_sdk.capture_message(message, "fatal")
+
+        logger.warning(message, stack_info=True)
+
+
+def _check_for_dirty_orders():
+    if getattr(dirty_transactions, 'order_ids', None) is None:
+        dirty_transactions.order_ids = set()
+    try:
+        if dirty_transactions.order_ids and dirty_transactions.order_ids != {None}:
+            _fail(
+                f"In the transaction that just ended, you created or modified an Order, OrderPosition, or OrderFee "
+                f"object in a way that you should have called `order.create_transactions()` afterwards. The transaction "
+                f"still went through and your data can be fixed with the `create_order_transactions` management command "
+                f"but you should update your code to prevent this from happening. Affected order IDs: {dirty_transactions.order_ids}"
+            )
+    finally:
+        dirty_transactions.order_ids.clear()
+
+
+def _transactions_mark_order_dirty(order_id, using=None):
+    if "PYTEST_CURRENT_TEST" in os.environ:
+        # We don't care about Order.objects.create() calls in test code so let's try to figure out if this is test code
+        # or not.
+        for frame in inspect.stack():
+            if 'pretix/base/models/orders' in frame.filename:
+                continue
+            elif 'test_' in frame.filename or 'conftest.py in frame.filename':
+                return
+            elif 'pretix/' in frame.filename or 'pretix_' in frame.filename:
+                # This went through non-test code, let's consider it non-test
+                break
+
+    if order_id is None:
+        return
+
+    conn = transaction.get_connection(using)
+    if not conn.in_atomic_block:
+        _fail(
+            "You modified an Order, OrderPosition, or OrderFee object in a way that should create "
+            "a new Transaction object within the same database transaction, however you are not "
+            "doing it inside a database transaction!"
+        )
+
+    if getattr(dirty_transactions, 'order_ids', None) is None:
+        dirty_transactions.order_ids = set()
+
+    if _check_for_dirty_orders not in [func for savepoint_id, func in conn.run_on_commit]:
+        transaction.on_commit(_check_for_dirty_orders, using)
+        dirty_transactions.order_ids.clear()  # This is necessary to clean up after old threads with rollbacked transactions
+
+    dirty_transactions.order_ids.add(order_id)
+
+
+def _transactions_mark_order_clean(order_id):
+    if getattr(dirty_transactions, 'order_ids', None) is None:
+        dirty_transactions.order_ids = set()
+    try:
+        dirty_transactions.order_ids.remove(order_id)
+    except KeyError:
+        pass

src/pretix/base/models/auth.py

@@ -44,7 +44,7 @@ from django.contrib.auth.models import (
 )
 from django.contrib.auth.tokens import default_token_generator
 from django.contrib.contenttypes.models import ContentType
-from django.db import models
+from django.db import IntegrityError, models, transaction
 from django.db.models import Q
 from django.utils.crypto import get_random_string, salted_hmac
 from django.utils.timezone import now
@@ -61,6 +61,10 @@ from pretix.helpers.urls import build_absolute_uri
 from .base import LoggingMixin
 
 
+class EmailAddressTakenError(IntegrityError):
+    pass
+
+
 class UserManager(BaseUserManager):
     """
     This is the user manager for our custom user model. See the User
@@ -83,6 +87,116 @@ class UserManager(BaseUserManager):
         user.save()
         return user
 
+    def get_or_create_for_backend(self, backend, identifier, email, set_always, set_on_creation):
+        """
+        This method should be used by third-party authentication backends to log in a user.
+        It either returns an already existing user or creates a new user.
+
+        In pretix 4.7 and earlier, email addresses were the only property to identify a user with.
+        Starting with pretix 4.8, backends SHOULD instead use a unique, immutable identifier
+        based on their backend data store to allow for changing email addresses.
+
+        This method transparently handles the conversion of old user accounts and adds the
+        backend identifier to their database record.
+
+        This method will never return users managed by a different authentication backend.
+        If you try to create an account with an email address already blocked by a different
+        authentication backend, :py:class:`EmailAddressTakenError` will be raised. In this case,
+        you should display a message to the user.
+
+        :param backend: The `identifier` attribute of the authentication backend
+        :param identifier: The unique, immutable identifier of this user, max. 190 characters
+        :param email: The user's email address
+        :param set_always: A dictionary of fields to update on the user model on every login
+        :param set_on_creation: A dictionary of fields to set on the user model if it's newly created
+        :return: A `User` instance.
+        """
+        if identifier is None:
+            raise ValueError('You need to supply a custom, unique identifier for this user.')
+        if email is None:
+            raise ValueError('You need to supply an email address for this user.')
+        if 'auth_backend_identifier' in set_always or 'auth_backend_identifier' in set_on_creation or \
+                'auth_backend' in set_always or 'auth_backend' in set_on_creation:
+            raise ValueError('You may not update auth_backend/auth_backend_identifier.')
+        if len(identifier) > 190:
+            raise ValueError('The user identifier must not be more than 190 characters.')
+
+        # Always update the email address
+        set_always.update({'email': email})
+
+        # First, check if we find the user based on it's backend-specific authenticator
+        try:
+            u = self.get(
+                auth_backend=backend,
+                auth_backend_identifier=identifier,
+            )
+            dirty = False
+            for k, v in set_always.items():
+                if getattr(u, k) != v:
+                    setattr(u, k, v)
+                    dirty = True
+            if dirty:
+                try:
+                    with transaction.atomic():
+                        u.save(update_fields=set_always.keys())
+                except IntegrityError:
+                    # This might only raise IntegrityError if the email address is used
+                    # by someone else
+                    raise EmailAddressTakenError()
+            return u
+        except self.model.DoesNotExist:
+            pass
+
+        # Second, check if we find the user based on their email address and this backend
+        try:
+            u = self.get(
+                auth_backend=backend,
+                auth_backend_identifier__isnull=True,
+                email=email,
+            )
+            u.auth_backend_identifier = identifier
+            for k, v in set_always.items():
+                setattr(u, k, v)
+            try:
+                with transaction.atomic():
+                    u.save(update_fields=['auth_backend_identifier'] + list(set_always.keys()))
+                return u
+            except IntegrityError:
+                # This might only raise IntegrityError if this code is being executed twice
+                # and runs into a race condition, this mechanism is taken from Django's
+                # get_or_create
+                try:
+                    return self.get(
+                        auth_backend=backend,
+                        auth_backend_identifier=identifier,
+                    )
+                except self.model.DoesNotExist:
+                    pass
+                raise
+        except self.model.DoesNotExist:
+            pass
+
+        # Third, create a new user
+        u = User(
+            auth_backend=backend,
+            auth_backend_identifier=identifier,
+            **set_on_creation,
+            **set_always,
+        )
+        try:
+            u.save(force_insert=True)
+            return u
+        except IntegrityError:
+            # This might either be a race condition or the email address is taken
+            # by a different backend
+            try:
+                return self.get(
+                    auth_backend=backend,
+                    auth_backend_identifier=identifier,
+                )
+            except self.model.DoesNotExist:
+                raise EmailAddressTakenError()
+
 
 def generate_notifications_token():
     return get_random_string(length=32)
@@ -113,8 +227,14 @@ class User(AbstractBaseUser, PermissionsMixin, LoggingMixin):
     :type date_joined: datetime
     :param locale: The user's preferred locale code.
     :type locale: str
+    :param needs_password_change: Whether this user's password needs to be changed.
+    :type needs_password_change: bool
     :param timezone: The user's preferred timezone.
     :type timezone: str
+    :param auth_backend: The identifier of the authentication backend plugin responsible for managing this user.
+    :type auth_backend: str
+    :param auth_backend_identifier: The native identifier of the user provided by a non-native authentication backend.
+    :type auth_backend_identifier: str
     """
 
     USERNAME_FIELD = 'email'
@@ -130,6 +250,8 @@ class User(AbstractBaseUser, PermissionsMixin, LoggingMixin):
                                    verbose_name=_('Is site admin'))
     date_joined = models.DateTimeField(auto_now_add=True,
                                        verbose_name=_('Date joined'))
+    needs_password_change = models.BooleanField(default=False,
+                                                verbose_name=_('Force user to select a new password'))
     locale = models.CharField(max_length=50,
                               choices=settings.LANGUAGES,
                               default=settings.LANGUAGE_CODE,
@@ -148,6 +270,7 @@ class User(AbstractBaseUser, PermissionsMixin, LoggingMixin):
     )
     notifications_token = models.CharField(max_length=255, default=generate_notifications_token)
     auth_backend = models.CharField(max_length=255, default='native')
+    auth_backend_identifier = models.CharField(max_length=190, db_index=True, null=True, blank=True)
     session_token = models.CharField(max_length=32, default=generate_session_token)
 
     objects = UserManager()
@@ -160,6 +283,7 @@ class User(AbstractBaseUser, PermissionsMixin, LoggingMixin):
         verbose_name = _("User")
         verbose_name_plural = _("Users")
         ordering = ('email',)
+        unique_together = (('auth_backend', 'auth_backend_identifier'),)
 
     def save(self, *args, **kwargs):
         self.email = self.email.lower()

src/pretix/base/models/checkin.py

@@ -221,7 +221,7 @@ class CheckinList(LoggedModel):
             return rules
 
         if operator in ('or', 'and') and seen_nonbool:
-            raise ValidationError(f'You cannot use OR/AND logic on a level below a comparison operator.')
+            raise ValidationError('You cannot use OR/AND logic on a level below a comparison operator.')
 
         for v in values:
             cls.validate_rules(v, seen_nonbool=seen_nonbool or operator not in ('or', 'and'), depth=depth + 1)

src/pretix/base/models/customers.py

@@ -25,9 +25,11 @@ from django.contrib.auth.hashers import (
     check_password, is_password_usable, make_password,
 )
 from django.db import models
+from django.db.models import F, Q
 from django.utils.crypto import get_random_string, salted_hmac
 from django.utils.translation import gettext_lazy as _, pgettext_lazy
 from django_scopes import ScopedManager, scopes_disabled
+from phonenumber_field.modelfields import PhoneNumberField
 
 from pretix.base.banlist import banned
 from pretix.base.models.base import LoggedModel
@@ -44,6 +46,7 @@ class Customer(LoggedModel):
     organizer = models.ForeignKey(Organizer, related_name='customers', on_delete=models.CASCADE)
     identifier = models.CharField(max_length=190, db_index=True, unique=True)
     email = models.EmailField(db_index=True, null=True, blank=False, verbose_name=_('E-mail'), max_length=190)
+    phone = PhoneNumberField(null=True, blank=True, verbose_name=_('Phone number'))
     password = models.CharField(verbose_name=_('Password'), max_length=128)
     name_cached = models.CharField(max_length=255, verbose_name=_('Full name'), blank=True)
     name_parts = models.JSONField(default=dict)
@@ -86,6 +89,7 @@ class Customer(LoggedModel):
         self.name_parts = {}
         self.name_cached = ''
         self.email = None
+        self.phone = None
         self.save()
         self.all_logentries().update(data={}, shredded=True)
         self.orders.all().update(customer=None)
@@ -168,6 +172,7 @@ class Customer(LoggedModel):
         return salted_hmac(key_salt, payload).hexdigest()
 
     def get_email_context(self):
+        from pretix.base.email import get_name_parts_localized
         ctx = {
             'name': self.name,
             'organizer': self.organizer.name,
@@ -176,13 +181,25 @@ class Customer(LoggedModel):
         for f, l, w in name_scheme['fields']:
             if f == 'full_name':
                 continue
-            ctx['name_%s' % f] = self.name_parts.get(f, '')
+            ctx['name_%s' % f] = get_name_parts_localized(self.name_parts, f)
+
+        if "concatenation_for_salutation" in name_scheme:
+            ctx['name_for_salutation'] = name_scheme["concatenation_for_salutation"](self.name_parts)
+        else:
+            ctx['name_for_salutation'] = name_scheme["concatenation"](self.name_parts)
+
         return ctx
 
     @property
     def stored_addresses(self):
         return self.invoice_addresses(manager='profiles')
 
+    def usable_memberships(self, for_event, testmode=False):
+        return self.memberships.active(for_event).with_usages().filter(
+            Q(membership_type__max_usages__isnull=True) | Q(usages__lt=F('membership_type__max_usages')),
+            testmode=testmode,
+        )
+
 
 class AttendeeProfile(models.Model):
     customer = models.ForeignKey(

src/pretix/base/models/event.py

@@ -57,6 +57,7 @@ from django.urls import reverse
 from django.utils.crypto import get_random_string
 from django.utils.formats import date_format
 from django.utils.functional import cached_property
+from django.utils.html import format_html
 from django.utils.timezone import make_aware, now
 from django.utils.translation import gettext, gettext_lazy as _
 from django_scopes import ScopedManager, scopes_disabled
@@ -145,7 +146,7 @@ class EventMixin:
             ("SHORT_" if short else "") + ("DATETIME_FORMAT" if self.settings.show_times and show_times else "DATE_FORMAT")
         )
 
-    def get_date_range_display(self, tz=None, force_show_end=False) -> str:
+    def get_date_range_display(self, tz=None, force_show_end=False, as_html=False) -> str:
         """
         Returns a formatted string containing the start date and the end date
         of the event with respect to the current locale and to the ``show_date_to``
@@ -153,8 +154,17 @@ class EventMixin:
         """
         tz = tz or self.timezone
         if (not self.settings.show_date_to and not force_show_end) or not self.date_to:
+            if as_html:
+                return format_html(
+                    "<time datetime=\"{}\">{}</time>",
+                    _date(self.date_from.astimezone(tz), "Y-m-d"),
+                    _date(self.date_from.astimezone(tz), "DATE_FORMAT"),
+                )
             return _date(self.date_from.astimezone(tz), "DATE_FORMAT")
-        return daterange(self.date_from.astimezone(tz), self.date_to.astimezone(tz))
+        return daterange(self.date_from.astimezone(tz), self.date_to.astimezone(tz), as_html)
+
+    def get_date_range_display_as_html(self, tz=None, force_show_end=False) -> str:
+        return self.get_date_range_display(tz, force_show_end, as_html=True)
 
     def get_time_range_display(self, tz=None, force_show_end=False) -> str:
         """
@@ -555,6 +565,8 @@ class Event(EventMixin, LoggedModel):
         self.settings.ticketoutput_pdf__enabled = True
         self.settings.ticketoutput_passbook__enabled = True
         self.settings.event_list_type = 'calendar'
+        self.settings.invoice_email_attachment = True
+        self.settings.name_scheme = 'given_family'
 
     @property
     def social_image(self):
@@ -653,21 +665,22 @@ class Event(EventMixin, LoggedModel):
 
         return locking.LockManager(self)
 
-    def get_mail_backend(self, timeout=None, force_custom=False):
+    def get_mail_backend(self, timeout=None):
         """
         Returns an email server connection, either by using the system-wide connection
         or by returning a custom one based on the event's settings.
         """
-        from pretix.base.email import CustomSMTPBackend
 
-        if self.settings.smtp_use_custom or force_custom:
-            return CustomSMTPBackend(host=self.settings.smtp_host,
-                                     port=self.settings.smtp_port,
-                                     username=self.settings.smtp_username,
-                                     password=self.settings.smtp_password,
-                                     use_tls=self.settings.smtp_use_tls,
-                                     use_ssl=self.settings.smtp_use_ssl,
-                                     fail_silently=False, timeout=timeout)
+        if self.settings.smtp_use_custom:
+            return get_connection(backend=settings.EMAIL_CUSTOM_SMTP_BACKEND,
+                                  host=self.settings.smtp_host,
+                                  port=self.settings.smtp_port,
+                                  username=self.settings.smtp_username,
+                                  password=self.settings.smtp_password,
+                                  use_tls=self.settings.smtp_use_tls,
+                                  use_ssl=self.settings.smtp_use_ssl,
+                                  fail_silently=False,
+                                  timeout=timeout)
         else:
             return get_connection(fail_silently=False)
 
@@ -1166,21 +1179,21 @@ class Event(EventMixin, LoggedModel):
             if not p.name.startswith('.') and getattr(p, 'visible', True)
         }
 
-    def set_active_plugins(self, modules, allow_restricted=False):
+    def set_active_plugins(self, modules, allow_restricted=frozenset()):
         plugins_active = self.get_plugins()
         plugins_available = self.get_available_plugins()
 
         enable = [m for m in modules if m not in plugins_active and m in plugins_available]
 
         for module in enable:
-            if getattr(plugins_available[module].app, 'restricted', False) and not allow_restricted:
+            if getattr(plugins_available[module].app, 'restricted', False) and module not in allow_restricted:
                 modules.remove(module)
             elif hasattr(plugins_available[module].app, 'installed'):
                 getattr(plugins_available[module].app, 'installed')(self)
 
         self.plugins = ",".join(modules)
 
-    def enable_plugin(self, module, allow_restricted=False):
+    def enable_plugin(self, module, allow_restricted=frozenset()):
         plugins_active = self.get_plugins()
         from pretix.presale.style import regenerate_css
 
@@ -1421,7 +1434,7 @@ class SubEvent(EventMixin, LoggedModel):
         return self.event.currency
 
     def allow_delete(self):
-        return not self.orderposition_set.exists()
+        return not self.orderposition_set.exists() and not self.transaction_set.exists()
 
     def delete(self, *args, **kwargs):
         clear_cache = kwargs.pop('clear_cache', False)

src/pretix/base/models/invoices.py

@@ -159,6 +159,8 @@ class Invoice(models.Model):
     # False: The invoice wasn't sent and never will, because sending was not configured at the time of the check.
     sent_to_organizer = models.BooleanField(null=True, blank=True)
 
+    sent_to_customer = models.DateTimeField(null=True, blank=True)
+
     file = models.FileField(null=True, blank=True, upload_to=invoice_filename, max_length=255)
 
     objects = ScopedManager(organizer='event__organizer')
@@ -235,7 +237,7 @@ class Invoice(models.Model):
     def _get_invoice_number_from_order(self):
         return '{order}-{count}'.format(
             order=self.order.code,
-            count=Invoice.objects.filter(event=self.event, order=self.order).count() + 1,
+            count=Invoice.objects.filter(event=self.event, prefix=self.prefix, invoice_no__startswith=f"{self.order.code}-", order=self.order).count() + 1,
         )
 
     def save(self, *args, **kwargs):
@@ -262,6 +264,7 @@ class Invoice(models.Model):
                     self.invoice_no = self._get_invoice_number_from_order()
                 try:
                     with transaction.atomic():
+                        self.full_invoice_no = self.prefix + self.invoice_no
                         return super().save(*args, **kwargs)
                 except DatabaseError:
                     # Suppress duplicate key errors and try again
@@ -300,6 +303,9 @@ class Invoice(models.Model):
     def __repr__(self):
         return '<Invoice {} / {}>'.format(self.full_invoice_no, self.pk)
 
+    def __str__(self):
+        return self.full_invoice_no
+
 
 class InvoiceLine(models.Model):
     """
@@ -323,6 +329,8 @@ class InvoiceLine(models.Model):
     :type event_date_from: datetime
     :param event_date_to: Event end date of the (sub)event at the time the invoice was created
     :type event_date_to: datetime
+    :param event_location: Event location of the (sub)event at the time the invoice was created
+    :type event_location: str
     :param item: The item this line refers to
     :type item: Item
     :param variation: The variation this line refers to
@@ -340,6 +348,7 @@ class InvoiceLine(models.Model):
     subevent = models.ForeignKey('SubEvent', null=True, blank=True, on_delete=models.PROTECT)
     event_date_from = models.DateTimeField(null=True)
     event_date_to = models.DateTimeField(null=True)
+    event_location = models.TextField(null=True, blank=True)
     item = models.ForeignKey('Item', null=True, blank=True, on_delete=models.PROTECT)
     variation = models.ForeignKey('ItemVariation', null=True, blank=True, on_delete=models.PROTECT)
     attendee_name = models.TextField(null=True, blank=True)

src/pretix/base/models/items.py

@@ -44,7 +44,7 @@ import dateutil.parser
 import pytz
 from django.conf import settings
 from django.core.exceptions import ValidationError
-from django.core.validators import RegexValidator
+from django.core.validators import MinValueValidator, RegexValidator
 from django.db import models
 from django.db.models import Q
 from django.utils import formats
@@ -479,12 +479,14 @@ class Item(LoggedModel):
     min_per_order = models.IntegerField(
         verbose_name=_('Minimum amount per order'),
         null=True, blank=True,
+        validators=[MinValueValidator(0)],
         help_text=_('This product can only be bought if it is added to the cart at least this many times. If you keep '
                     'the field empty or set it to 0, there is no special limit for this product.')
     )
     max_per_order = models.IntegerField(
         verbose_name=_('Maximum amount per order'),
         null=True, blank=True,
+        validators=[MinValueValidator(0)],
         help_text=_('This product can only be bought at most this many times within one order. If you keep the field '
                     'empty or set it to 0, there is no special limit for this product. The limit for the maximum '
                     'number of items in the whole order applies regardless.')
@@ -523,6 +525,12 @@ class Item(LoggedModel):
         verbose_name=_('Allowed membership types'),
         blank=True,
     )
+    require_membership_hidden = models.BooleanField(
+        verbose_name=_('Hide without a valid membership'),
+        help_text=_('Do not show this unless the customer is logged in and has a valid membership. Be aware that '
+                    'this means it will never be visible in the widget.'),
+        default=False,
+    )
     grant_membership_type = models.ForeignKey(
         'MembershipType',
         null=True, blank=True,
@@ -687,9 +695,9 @@ class Item(LoggedModel):
         return res
 
     def allow_delete(self):
-        from pretix.base.models.orders import OrderPosition
+        from pretix.base.models.orders import OrderPosition, Transaction
 
-        return not OrderPosition.all.filter(item=self).exists()
+        return not Transaction.objects.filter(item=self).exists() and not OrderPosition.all.filter(item=self).exists()
 
     @property
     def includes_mixed_tax_rate(self):
@@ -758,6 +766,9 @@ class ItemVariation(models.Model):
     :type default_price: decimal.Decimal
     :param original_price: The item's "original" price. Will not be used for any calculations, will just be shown.
     :type original_price: decimal.Decimal
+    :param require_approval: If set to ``True``, orders containing this variation can only be processed and paid after
+    approval by an administrator
+    :type require_approval: bool
     """
     item = models.ForeignKey(
         Item,
@@ -793,6 +804,13 @@ class ItemVariation(models.Model):
         help_text=_('If set, this will be displayed next to the current price to show that the current price is a '
                     'discounted one. This is just a cosmetic setting and will not actually impact pricing.')
     )
+    require_approval = models.BooleanField(
+        verbose_name=_('Require approval'),
+        default=False,
+        help_text=_('If this variation is part of an order, the order will be put into an "approval" state and '
+                    'will need to be confirmed by you before it can be paid and completed. You can use this e.g. for '
+                    'discounted tickets that are only available to specific groups.'),
+    )
     require_membership = models.BooleanField(
         verbose_name=_('Require a valid membership'),
         default=False,
@@ -802,6 +820,12 @@ class ItemVariation(models.Model):
         verbose_name=_('Membership types'),
         blank=True,
     )
+    require_membership_hidden = models.BooleanField(
+        verbose_name=_('Hide without a valid membership'),
+        help_text=_('Do not show this unless the customer is logged in and has a valid membership. Be aware that '
+                    'this means it will never be visible in the widget.'),
+        default=False,
+    )
     available_from = models.DateTimeField(
         verbose_name=_("Available from"),
         null=True, blank=True,
@@ -820,7 +844,7 @@ class ItemVariation(models.Model):
         blank=True,
     )
     hide_without_voucher = models.BooleanField(
-        verbose_name=_('This variation will only be shown if a voucher matching the product is redeemed.'),
+        verbose_name=_('Show only if a matching voucher is redeemed.'),
         default=False,
         help_text=_('This variation will be hidden from the event page until the user enters a voucher '
                     'that unlocks this variation.')
@@ -946,10 +970,13 @@ class ItemVariation(models.Model):
         return self.position < other.position
 
     def allow_delete(self):
-        from pretix.base.models.orders import CartPosition, OrderPosition
+        from pretix.base.models.orders import (
+            CartPosition, OrderPosition, Transaction,
+        )
 
         return (
-            not OrderPosition.objects.filter(variation=self).exists()
+            not Transaction.objects.filter(variation=self).exists()
+            and not OrderPosition.objects.filter(variation=self).exists()
             and not CartPosition.objects.filter(variation=self).exists()
         )
 
@@ -1672,7 +1699,7 @@ class Quota(LoggedModel):
             if event != item.event:
                 raise ValidationError(_('One or more items do not belong to this event.'))
             if item.has_variations:
-                if not any(var.item == item for var in variations):
+                if not variations or not any(var.item == item for var in variations):
                     raise ValidationError(_('One or more items has variations but none of these are in the variations list.'))
 
     @staticmethod

src/pretix/base/models/memberships.py

@@ -95,6 +95,7 @@ class MembershipQuerySet(models.QuerySet):
 
     def active(self, ev):
         return self.filter(
+            canceled=False,
             date_start__lte=ev.date_from,
             date_end__gte=ev.date_from
         )
@@ -175,7 +176,7 @@ class Membership(models.Model):
         else:
             dt = now()
 
-        return dt >= self.date_start and dt <= self.date_end
+        return not self.canceled and dt >= self.date_start and dt <= self.date_end
 
     def allow_delete(self):
         return self.testmode and not self.orderposition_set.exists()

src/pretix/base/models/orders.py

@@ -75,11 +75,14 @@ from pretix.base.email import get_email_context
 from pretix.base.i18n import language
 from pretix.base.models import Customer, User
 from pretix.base.reldate import RelativeDateWrapper
-from pretix.base.services.locking import NoLockManager
+from pretix.base.services.locking import LOCK_TIMEOUT, NoLockManager
 from pretix.base.settings import PERSON_NAME_SCHEMES
 from pretix.base.signals import order_gracefully_delete
 
 from ...helpers.countries import CachedCountries, FastCountryField
+from ._transactions import (
+    _fail, _transactions_mark_order_clean, _transactions_mark_order_dirty,
+)
 from .base import LockModel, LoggedModel
 from .event import Event, SubEvent
 from .items import Item, ItemVariation, Question, QuestionOption, Quota
@@ -262,6 +265,11 @@ class Order(LockModel, LoggedModel):
     def __str__(self):
         return self.full_code
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        if 'require_approval' not in self.get_deferred_fields() and 'status' not in self.get_deferred_fields():
+            self.__initial_status_paid_or_pending = self.status in (Order.STATUS_PENDING, Order.STATUS_PAID) and not self.require_approval
+
     def gracefully_delete(self, user=None, auth=None):
         from . import GiftCard, GiftCardTransaction, Membership, Voucher
 
@@ -289,6 +297,7 @@ class Order(LockModel, LoggedModel):
         OrderPosition.all.filter(order=self, addon_to__isnull=False).delete()
         OrderPosition.all.filter(order=self).delete()
         OrderFee.all.filter(order=self).delete()
+        Transaction.objects.filter(order=self).delete()
         self.refunds.all().delete()
         self.payments.all().delete()
         self.event.cache.delete('complain_testmode_orders')
@@ -444,7 +453,27 @@ class Order(LockModel, LoggedModel):
             self.datetime = now()
         if not self.expires:
             self.set_expires()
-        super().save(**kwargs)
+
+        is_new = not self.pk
+        update_fields = kwargs.get('update_fields', [])
+        if 'require_approval' not in self.get_deferred_fields() and 'status' not in self.get_deferred_fields():
+            status_paid_or_pending = self.status in (Order.STATUS_PENDING, Order.STATUS_PAID) and not self.require_approval
+            if status_paid_or_pending != self.__initial_status_paid_or_pending:
+                _transactions_mark_order_dirty(self.pk, using=kwargs.get('using', None))
+        elif (
+            not kwargs.get('force_save_with_deferred_fields', None) and
+            (not update_fields or ('require_approval' not in update_fields and 'status' not in update_fields))
+        ):
+            _fail("It is unsafe to call save() on an OrderFee with deferred fields since we can't check if you missed "
+                  "creating a transaction. Call save(force_save_with_deferred_fields=True) if you really want to do "
+                  "this.")
+
+        r = super().save(**kwargs)
+
+        if is_new:
+            _transactions_mark_order_dirty(self.pk, using=kwargs.get('using', None))
+
+        return r
 
     def touch(self):
         self.save(update_fields=['last_modified'])
@@ -552,6 +581,7 @@ class Order(LockModel, LoggedModel):
         Returns whether or not this order can be canceled by the user.
         """
         from .checkin import Checkin
+        from .items import ItemAddOn
 
         if self.status not in (Order.STATUS_PENDING, Order.STATUS_PAID) or not self.count_positions:
             return False
@@ -577,7 +607,10 @@ class Order(LockModel, LoggedModel):
         if self.user_change_deadline and now() > self.user_change_deadline:
             return False
 
-        return self.event.settings.change_allow_user_variation and any([op.has_variations for op in positions])
+        return (
+            (self.event.settings.change_allow_user_variation and any([op.has_variations for op in positions])) or
+            (self.event.settings.change_allow_user_addons and ItemAddOn.objects.filter(base_item_id__in=[op.item_id for op in positions]).exists())
+        )
 
     @property
     @scopes_disabled()
@@ -917,7 +950,7 @@ class Order(LockModel, LoggedModel):
                   context: Dict[str, Any]=None, log_entry_type: str='pretix.event.order.email.sent',
                   user: User=None, headers: dict=None, sender: str=None, invoices: list=None,
                   auth=None, attach_tickets=False, position: 'OrderPosition'=None, auto_email=True,
-                  attach_ical=False):
+                  attach_ical=False, attach_other_files: list=None):
         """
         Sends an email to the user that placed this order. Basically, this method does two things:
 
@@ -943,7 +976,7 @@ class Order(LockModel, LoggedModel):
             SendMailException, TolerantDict, mail, render_mail,
         )
 
-        if not self.email:
+        if not self.email and not (position and position.attendee_email):
             return
 
         for k, v in self.event.meta_data.items():
@@ -961,7 +994,8 @@ class Order(LockModel, LoggedModel):
                     recipient, subject, template, context,
                     self.event, self.locale, self, headers=headers, sender=sender,
                     invoices=invoices, attach_tickets=attach_tickets,
-                    position=position, auto_email=auto_email, attach_ical=attach_ical
+                    position=position, auto_email=auto_email, attach_ical=attach_ical,
+                    attach_other_files=attach_other_files,
                 )
             except SendMailException:
                 raise
@@ -999,6 +1033,59 @@ class Order(LockModel, LoggedModel):
                 continue
             yield op
 
+    def create_transactions(self, is_new=False, positions=None, fees=None, dt_now=None, migrated=False,
+                            _backfill_before_cancellation=False, save=True):
+        dt_now = dt_now or now()
+
+        # Count the transactions we already have
+        current_transaction_count = Counter()
+        if not is_new:
+            for t in Transaction.objects.filter(order=self):  # do not use related manager, we want to avoid cached data
+                current_transaction_count[Transaction.key(t)] += t.count
+
+        # Count the transactions we'd actually need
+        target_transaction_count = Counter()
+        if (_backfill_before_cancellation or self.status in (Order.STATUS_PENDING, Order.STATUS_PAID)) and not self.require_approval:
+            positions = self.positions.all() if positions is None else positions
+            for p in positions:
+                if p.canceled and not _backfill_before_cancellation:
+                    continue
+                target_transaction_count[Transaction.key(p)] += 1
+
+            fees = self.fees.all() if fees is None else fees
+            for f in fees:
+                if f.canceled and not _backfill_before_cancellation:
+                    continue
+                target_transaction_count[Transaction.key(f)] += 1
+
+        keys = set(target_transaction_count.keys()) | set(current_transaction_count.keys())
+        create = []
+        for k in keys:
+            positionid, itemid, variationid, subeventid, price, taxrate, taxruleid, taxvalue, feetype, internaltype = k
+            d = target_transaction_count[k] - current_transaction_count[k]
+            if d:
+                create.append(Transaction(
+                    order=self,
+                    datetime=dt_now,
+                    migrated=migrated,
+                    positionid=positionid,
+                    count=d,
+                    item_id=itemid,
+                    variation_id=variationid,
+                    subevent_id=subeventid,
+                    price=price,
+                    tax_rate=taxrate,
+                    tax_rule_id=taxruleid,
+                    tax_value=taxvalue,
+                    fee_type=feetype,
+                    internal_type=internaltype,
+                ))
+        create.sort(key=lambda t: (0 if t.count < 0 else 1, t.positionid or 0))
+        if save:
+            Transaction.objects.bulk_create(create)
+        _transactions_mark_order_clean(self.pk)
+        return create
+
 
 def answerfile_name(instance, filename: str) -> str:
     secret = get_random_string(length=32, allowed_chars=string.ascii_letters + string.digits)
@@ -1224,6 +1311,7 @@ class AbstractPosition(models.Model):
     seat = models.ForeignKey(
         'Seat', null=True, blank=True, on_delete=models.PROTECT
     )
+    is_bundled = models.BooleanField(default=False)
 
     company = models.CharField(max_length=255, blank=True, verbose_name=_('Company name'), null=True)
     street = models.TextField(verbose_name=_('Address'), blank=True, null=True)
@@ -1354,6 +1442,15 @@ class AbstractPosition(models.Model):
         lines = [r.strip() for r in lines if r]
         return '\n'.join(lines).strip()
 
+    def requires_approval(self, invoice_address=None):
+        if self.item.require_approval:
+            return True
+        if self.variation and self.variation.require_approval:
+            return True
+        if self.item.tax_rule and self.item.tax_rule._require_approval(invoice_address):
+            return True
+        return False
+
 
 class OrderPayment(models.Model):
     """
@@ -1460,7 +1557,7 @@ class OrderPayment(models.Model):
         return self.order.event.get_payment_providers(cached=True).get(self.provider)
 
     @transaction.atomic()
-    def _mark_paid(self, force, count_waitinglist, user, auth, ignore_date=False, overpaid=False):
+    def _mark_paid_inner(self, force, count_waitinglist, user, auth, ignore_date=False, overpaid=False):
         from pretix.base.signals import order_paid
         can_be_paid = self.order._can_be_paid(count_waitinglist=count_waitinglist, ignore_date=ignore_date, force=force)
         if can_be_paid is not True:
@@ -1468,6 +1565,7 @@ class OrderPayment(models.Model):
                 'message': can_be_paid
             }, user=user, auth=auth)
             raise Quota.QuotaExceededException(can_be_paid)
+        status_change = self.order.status != Order.STATUS_PENDING
         self.order.status = Order.STATUS_PAID
         self.order.save(update_fields=['status'])
 
@@ -1481,6 +1579,8 @@ class OrderPayment(models.Model):
         if overpaid:
             self.order.log_action('pretix.event.order.overpaid', {}, user=user, auth=auth)
         order_paid.send(self.order.event, order=self.order)
+        if status_change:
+            self.order.create_transactions()
 
     def fail(self, info=None, user=None, auth=None):
         """
@@ -1533,10 +1633,6 @@ class OrderPayment(models.Model):
         :type mail_text: str
         :raises Quota.QuotaExceededException: if the quota is exceeded and ``force`` is ``False``
         """
-        from pretix.base.services.invoices import (
-            generate_invoice, invoice_qualified,
-        )
-
         with transaction.atomic():
             locked_instance = OrderPayment.objects.select_for_update().get(pk=self.pk)
             if locked_instance.state == self.PAYMENT_STATE_CONFIRMED:
@@ -1580,7 +1676,15 @@ class OrderPayment(models.Model):
             ))
             return
 
-        if (self.order.status == Order.STATUS_PENDING and self.order.expires > now() + timedelta(hours=12)) or not lock:
+        self._mark_order_paid(count_waitinglist, send_mail, force, user, auth, mail_text, ignore_date, lock, payment_sum - refund_sum)
+
+    def _mark_order_paid(self, count_waitinglist=True, send_mail=True, force=False, user=None, auth=None, mail_text='',
+                         ignore_date=False, lock=True, payment_refund_sum=0):
+        from pretix.base.services.invoices import (
+            generate_invoice, invoice_qualified,
+        )
+
+        if (self.order.status == Order.STATUS_PENDING and self.order.expires > now() + timedelta(seconds=LOCK_TIMEOUT * 2)) or not lock:
             # Performance optimization. In this case, there's really no reason to lock everything and an atomic
             # database transaction is more than enough.
             lockfn = NoLockManager
@@ -1588,8 +1692,8 @@ class OrderPayment(models.Model):
             lockfn = self.order.event.lock
 
         with lockfn():
-            self._mark_paid(force, count_waitinglist, user, auth, overpaid=payment_sum - refund_sum > self.order.total,
-                            ignore_date=ignore_date)
+            self._mark_paid_inner(force, count_waitinglist, user, auth, overpaid=payment_refund_sum > self.order.total,
+                                  ignore_date=ignore_date)
 
         invoice = None
         if invoice_qualified(self.order):
@@ -1620,10 +1724,10 @@ class OrderPayment(models.Model):
             email_context = get_email_context(event=self.order.event, order=self.order, position=position)
             email_subject = _('Event registration confirmed: %(code)s') % {'code': self.order.code}
             try:
-                self.order.send_mail(
+                position.send_mail(
                     email_subject, email_template, email_context,
                     'pretix.event.order.email.order_paid', user,
-                    invoices=[], position=position,
+                    invoices=[],
                     attach_tickets=True,
                     attach_ical=self.order.event.settings.mail_attach_ical
                 )
@@ -1958,6 +2062,12 @@ class OrderFee(models.Model):
     def net_value(self):
         return self.value - self.tax_value
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        if not self.get_deferred_fields():
+            self.__initial_transaction_key = Transaction.key(self)
+            self.__initial_canceled = self.canceled
+
     def __str__(self):
         if self.description:
             return '{} - {}'.format(self.get_fee_type_display(), self.description)
@@ -1996,6 +2106,15 @@ class OrderFee(models.Model):
         if self.tax_rate is None:
             self._calculate_tax()
         self.order.touch()
+
+        if not self.get_deferred_fields():
+            if Transaction.key(self) != self.__initial_transaction_key or self.canceled != self.__initial_canceled or not self.pk:
+                _transactions_mark_order_dirty(self.order_id, using=kwargs.get('using', None))
+        elif not kwargs.get('force_save_with_deferred_fields', None):
+            _fail("It is unsafe to call save() on an OrderFee with deferred fields since we can't check if you missed "
+                  "creating a transaction. Call save(force_save_with_deferred_fields=True) if you really want to do "
+                  "this.")
+
         return super().save(*args, **kwargs)
 
     def delete(self, **kwargs):
@@ -2010,7 +2129,7 @@ class OrderPosition(AbstractPosition):
     AbstractPosition.
 
     The default ``OrderPosition.objects`` manager only contains fees that are not ``canceled``. If
-    you ant all objects, you need to use ``OrderPosition.all`` instead.
+    you want all objects, you need to use ``OrderPosition.all`` instead.
 
     :param order: The order this position is a part of
     :type order: Order
@@ -2061,6 +2180,12 @@ class OrderPosition(AbstractPosition):
     all = ScopedManager(organizer='order__event__organizer')
     objects = ActivePositionManager()
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        if not self.get_deferred_fields():
+            self.__initial_transaction_key = Transaction.key(self)
+            self.__initial_canceled = self.canceled
+
     class Meta:
         verbose_name = _("Order position")
         verbose_name_plural = _("Order positions")
@@ -2104,6 +2229,7 @@ class OrderPosition(AbstractPosition):
             op._calculate_tax()
             op.positionid = i + 1
             op.save()
+            ops.append(op)
             cp_mapping[cartpos.pk] = op
             for answ in cartpos.answers.all():
                 answ.orderposition = op
@@ -2169,6 +2295,14 @@ class OrderPosition(AbstractPosition):
         if not self.pseudonymization_id:
             self.assign_pseudonymization_id()
 
+        if not self.get_deferred_fields():
+            if Transaction.key(self) != self.__initial_transaction_key or self.canceled != self.__initial_canceled or not self.pk:
+                _transactions_mark_order_dirty(self.order_id, using=kwargs.get('using', None))
+        elif not kwargs.get('force_save_with_deferred_fields', None):
+            _fail("It is unsafe to call save() on an OrderFee with deferred fields since we can't check if you missed "
+                  "creating a transaction. Call save(force_save_with_deferred_fields=True) if you really want to do "
+                  "this.")
+
         return super().save(*args, **kwargs)
 
     @scopes_disabled()
@@ -2192,7 +2326,7 @@ class OrderPosition(AbstractPosition):
     def send_mail(self, subject: str, template: Union[str, LazyI18nString],
                   context: Dict[str, Any]=None, log_entry_type: str='pretix.event.order.email.sent',
                   user: User=None, headers: dict=None, sender: str=None, invoices: list=None,
-                  auth=None, attach_tickets=False, attach_ical=False):
+                  auth=None, attach_tickets=False, attach_ical=False, attach_other_files: list=None):
         """
         Sends an email to the attendee. Basically, this method does two things:
 
@@ -2212,7 +2346,7 @@ class OrderPosition(AbstractPosition):
         :param attach_ical: Attach relevant ICS files
         """
         from pretix.base.services.mail import (
-            SendMailException, mail, render_mail,
+            SendMailException, TolerantDict, mail, render_mail,
         )
 
         if not self.attendee_email:
@@ -2225,6 +2359,7 @@ class OrderPosition(AbstractPosition):
             recipient = self.attendee_email
             try:
                 email_content = render_mail(template, context)
+                subject = str(subject).format_map(TolerantDict(context))
                 mail(
                     recipient, subject, template, context,
                     self.event, self.order.locale, order=self.order, headers=headers, sender=sender,
@@ -2232,6 +2367,7 @@ class OrderPosition(AbstractPosition):
                     invoices=invoices,
                     attach_tickets=attach_tickets,
                     attach_ical=attach_ical,
+                    attach_other_files=attach_other_files,
                 )
             except SendMailException:
                 raise
@@ -2263,6 +2399,151 @@ class OrderPosition(AbstractPosition):
             )
 
 
+class Transaction(models.Model):
+    """
+    Transactions are a data structure that is redundant on the first sight but makes it possible to create good
+    financial reporting.
+
+    To understand this, think of "orders" as something like a contractual relationship between the organizer and the
+    customer which requires to customer to pay some money and the organizer to provide a ticket.
+
+    The ``Order``, ``OrderPosition``, and ``OrderFee`` models combined give a representation of the current contractual
+    status of this relationship, i.e. how much and what is owed. The ``OrderPayment`` and ``OrderRefund`` models indicate
+    the "other side" of the relationship, i.e. how much of the financial obligation has been met so far.
+
+    However, while ``OrderPayment`` and ``OrderRefund`` objects are "final" and no longer change once they reached their
+    final state, ``Order``, ``OrderPosition`` and ``OrderFee`` are highly mutable and can change at any time, e.g. if
+    the customer moves their booking to a different day or a discount is applied retroactively.
+
+    Therefore those models can be used to answer the question "how many tickets of type X have been sold for my event
+    as of today?" but they cannot accurately answer the question "how many tickets of type X have been sold for my event
+    as of last month?" because they lack this kind of historical information.
+
+    Transactions help here because they are "immutable copies" or "modification records" of call positions and fees
+    at the time of their creation and change. They only record data that is usually relevant for financial reporting,
+    such as amounts, prices, products and dates involved. They do not record data like attendee names etc.
+
+    Even before the introduction of the Transaction Model pretix *did* store historical data for auditability in the
+    LogEntry model. However, it's almost impossible to do efficient reporting on that data.
+
+    Transactions should never be generated manually but only through the ``order.create_transactions()``
+    method which should be called **within the same database transaction**.
+
+    The big downside of this approach is that you need to remember to update transaction records every time you change
+    or create orders in new code paths. The mechanism introduced in ``pretix.base.models._transactions`` as well as
+    the ``save()`` methods of ``Order``, ``OrderPosition`` and ``OrderFee`` intends to help you notice if you missed
+    it. The only thing this *doesn't* catch is usage of ``OrderPosition.objects.bulk_create`` (and likewise for
+    ``bulk_update`` and ``OrderFee``).
+
+    :param id: ID of the transaction
+    :param order: Order the transaction belongs to
+    :param datetime: Date and time of the transaction
+    :param migrated: Whether this object was reconstructed because the order was created before transactions where introduced
+    :param positionid: Affected Position ID, in case this transaction represents a change in an order position
+    :param count: An amount, multiplicator for price etc. For order positions this can *currently* only be -1 or +1, for
+                  fees it can also be more in special cases
+    :param item: ``Item``, in case this transaction represents a change in an order position
+    :param variation: ``ItemVariation``, in case this transaction represents a change in an order position
+    :param subevent: ``subevent``, in case this transaction represents a change in an order position
+    :param price: Price of the changed position
+    :param tax_rate: Tax rate of the changed position
+    :param tax_rule: Used tax rule
+    :param tax_value: Tax value in event currency
+    :param fee_type: Fee type code in case this transaction represents a change in an order fee
+    :param internal_type: Internal fee type in case this transaction represents a change in an order fee
+    """
+    id = models.BigAutoField(primary_key=True)
+    order = models.ForeignKey(
+        Order,
+        verbose_name=_("Order"),
+        related_name='transactions',
+        on_delete=models.PROTECT
+    )
+    created = models.DateTimeField(
+        auto_now_add=True,
+        db_index=True,
+    )
+    datetime = models.DateTimeField(
+        verbose_name=_("Date"),
+        db_index=True,
+    )
+    migrated = models.BooleanField(
+        default=False
+    )
+    positionid = models.PositiveIntegerField(default=1, null=True, blank=True)
+    count = models.IntegerField(
+        default=1
+    )
+    item = models.ForeignKey(
+        Item,
+        null=True, blank=True,
+        verbose_name=_("Item"),
+        on_delete=models.PROTECT
+    )
+    variation = models.ForeignKey(
+        ItemVariation,
+        null=True, blank=True,
+        verbose_name=_("Variation"),
+        on_delete=models.PROTECT
+    )
+    subevent = models.ForeignKey(
+        SubEvent,
+        null=True, blank=True,
+        on_delete=models.PROTECT,
+        verbose_name=pgettext_lazy("subevent", "Date"),
+    )
+    price = models.DecimalField(
+        decimal_places=2, max_digits=10,
+        verbose_name=_("Price")
+    )
+    tax_rate = models.DecimalField(
+        max_digits=7, decimal_places=2,
+        verbose_name=_('Tax rate')
+    )
+    tax_rule = models.ForeignKey(
+        'TaxRule',
+        on_delete=models.PROTECT,
+        null=True, blank=True
+    )
+    tax_value = models.DecimalField(
+        max_digits=10, decimal_places=2,
+        verbose_name=_('Tax value')
+    )
+    fee_type = models.CharField(
+        max_length=100, choices=OrderFee.FEE_TYPES, null=True, blank=True
+    )
+    internal_type = models.CharField(max_length=255, null=True, blank=True)
+
+    class Meta:
+        ordering = 'datetime', 'pk'
+
+    def save(self, *args, **kwargs):
+        if not self.fee_type and not self.item:
+            raise ValidationError('Should set either item or fee type')
+        return super().save(*args, **kwargs)
+
+    @staticmethod
+    def key(obj):
+        if isinstance(obj, Transaction):
+            return (obj.positionid, obj.item_id, obj.variation_id, obj.subevent_id, obj.price, obj.tax_rate,
+                    obj.tax_rule_id, obj.tax_value, obj.fee_type, obj.internal_type)
+        elif isinstance(obj, OrderPosition):
+            return (obj.positionid, obj.item_id, obj.variation_id, obj.subevent_id, obj.price, obj.tax_rate,
+                    obj.tax_rule_id, obj.tax_value, None, None)
+        elif isinstance(obj, OrderFee):
+            return (None, None, None, None, obj.value, obj.tax_rate,
+                    obj.tax_rule_id, obj.tax_value, obj.fee_type, obj.internal_type)
+        raise ValueError('invalid state')  # noqa
+
+    @property
+    def full_price(self):
+        return self.price * self.count
+
+    @property
+    def full_tax_value(self):
+        return self.tax_value * self.count
+
+
 class CartPosition(AbstractPosition):
     """
     A cart position is similar to an order line, except that it is not
@@ -2301,7 +2582,6 @@ class CartPosition(AbstractPosition):
         max_digits=10, decimal_places=2,
         null=True, blank=True
     )
-    is_bundled = models.BooleanField(default=False)
 
     objects = ScopedManager(organizer='event__organizer')
 
@@ -2351,8 +2631,7 @@ class InvoiceAddress(models.Model):
     country = FastCountryField(verbose_name=_('Country'), blank=False, blank_label=_('Select country'),
                                countries=CachedCountries)
     state = models.CharField(max_length=255, verbose_name=pgettext_lazy('address', 'State'), blank=True)
-    vat_id = models.CharField(max_length=255, blank=True, verbose_name=_('VAT ID'),
-                              help_text=_('Only for business customers within the EU.'))
+    vat_id = models.CharField(max_length=255, blank=True, verbose_name=_('VAT ID'))
     vat_id_validated = models.BooleanField(default=False)
     custom_field = models.CharField(max_length=255, null=True, blank=True)
     internal_reference = models.TextField(

src/pretix/base/models/organizer.py

@@ -36,6 +36,7 @@ import string
 from datetime import date, datetime, time
 
 import pytz
+from django.conf import settings
 from django.core.mail import get_connection
 from django.core.validators import MinLengthValidator, RegexValidator
 from django.db import models
@@ -97,10 +98,21 @@ class Organizer(LoggedModel):
         return self.name
 
     def save(self, *args, **kwargs):
+        is_new = not self.pk
         obj = super().save(*args, **kwargs)
-        self.get_cache().clear()
+        if is_new:
+            self.set_defaults()
+        else:
+            self.get_cache().clear()
         return obj
 
+    def set_defaults(self):
+        """
+        This will be called after organizer creation.
+        This way, we can use this to introduce new default settings to pretix that do not affect existing organizers.
+        """
+        self.settings.cookie_consent = True
+
     def get_cache(self):
         """
         Returns an :py:class:`ObjectRelatedCache` object. This behaves equivalent to
@@ -179,21 +191,20 @@ class Organizer(LoggedModel):
             e.delete()
         self.teams.all().delete()
 
-    def get_mail_backend(self, timeout=None, force_custom=False):
+    def get_mail_backend(self, timeout=None):
         """
         Returns an email server connection, either by using the system-wide connection
         or by returning a custom one based on the organizer's settings.
         """
-        from pretix.base.email import CustomSMTPBackend
-
-        if self.settings.smtp_use_custom or force_custom:
-            return CustomSMTPBackend(host=self.settings.smtp_host,
-                                     port=self.settings.smtp_port,
-                                     username=self.settings.smtp_username,
-                                     password=self.settings.smtp_password,
-                                     use_tls=self.settings.smtp_use_tls,
-                                     use_ssl=self.settings.smtp_use_ssl,
-                                     fail_silently=False, timeout=timeout)
+        if self.settings.smtp_use_custom:
+            return get_connection(backend=settings.EMAIL_CUSTOM_SMTP_BACKEND,
+                                  host=self.settings.smtp_host,
+                                  port=self.settings.smtp_port,
+                                  username=self.settings.smtp_username,
+                                  password=self.settings.smtp_password,
+                                  use_tls=self.settings.smtp_use_tls,
+                                  use_ssl=self.settings.smtp_use_ssl,
+                                  fail_silently=False, timeout=timeout)
         else:
             return get_connection(fail_silently=False)
 

src/pretix/base/models/seating.py

@@ -26,7 +26,7 @@ import jsonschema
 from django.contrib.staticfiles import finders
 from django.core.exceptions import ValidationError
 from django.db import models
-from django.db.models import Exists, F, OuterRef, Q, Value
+from django.db.models import Exists, F, OuterRef, Q, Subquery, Value
 from django.db.models.functions import Power
 from django.utils.deconstruct import deconstructible
 from django.utils.timezone import now
@@ -281,10 +281,26 @@ class Seat(models.Model):
             q = Q(has_order=True) | Q(has_voucher=True)
             if ignore_cart is not True:
                 q |= Q(has_cart=True)
+
+            # The following looks like it makes no sense. Why wouldn't we just use ``Value(self.x)``, we already now
+            # the value? The reason is that x and y are floating point values generated from our JSON files. As it turns
+            # out, PostgreSQL MIGHT store floating point values with a different precision based on the underlying system
+            # architecture. So if we generate e.g. 670.247128887222289 from the JSON file and store it to the database,
+            # PostgreSQL will store it as 670.247128887222289 internally. However if we query it again, we only get
+            # 670.247128887222 back. But if we do calculations with a field in PostgreSQL itself, it uses the full
+            # precision for the calculation.
+            # We don't actually care about the results with this precision, but we care that the results from this
+            # function are exactly the same as from event.free_seats(), so we do this subquery trick to deal with
+            # PostgreSQL's internal values in both cases.
+            # In the long run, we probably just want to round the numbers on insert...
+            # See also https://www.postgresql.org/docs/11/runtime-config-client.html#GUC-EXTRA-FLOAT-DIGITS
+            self_x = Subquery(Seat.objects.filter(pk=self.pk).values('x'))
+            self_y = Subquery(Seat.objects.filter(pk=self.pk).values('y'))
+
             qs_closeby_taken = qs_annotated.annotate(
                 distance=(
-                    Power(F('x') - Value(self.x), Value(2), output_field=models.FloatField()) +
-                    Power(F('y') - Value(self.y), Value(2), output_field=models.FloatField())
+                    Power(F('x') - self_x, Value(2), output_field=models.FloatField()) +
+                    Power(F('y') - self_y, Value(2), output_field=models.FloatField())
                 )
             ).exclude(pk=self.pk).filter(
                 q,

src/pretix/base/models/tax.py

@@ -25,7 +25,6 @@ from decimal import Decimal
 from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils.formats import localize
-from django.utils.timezone import get_current_timezone, now
 from django.utils.translation import gettext_lazy as _, pgettext
 from i18nfield.fields import I18nCharField
 from i18nfield.strings import LazyI18nString
@@ -82,6 +81,15 @@ class TaxedPrice:
             name=self.name,
         )
 
+    def __eq__(self, other):
+        return (
+            self.gross == other.gross and
+            self.net == other.net and
+            self.tax == other.tax and
+            self.rate == other.rate and
+            self.name == other.name
+        )
+
 
 TAXED_ZERO = TaxedPrice(
     gross=Decimal('0.00'),
@@ -93,7 +101,7 @@ TAXED_ZERO = TaxedPrice(
 
 EU_COUNTRIES = {
     'AT', 'BE', 'BG', 'HR', 'CY', 'CZ', 'DK', 'EE', 'FI', 'FR', 'DE', 'GR', 'HU', 'IE', 'IT', 'LV', 'LT', 'LU', 'MT',
-    'NL', 'PL', 'PT', 'RO', 'SK', 'SI', 'ES', 'SE', 'GB'
+    'NL', 'PL', 'PT', 'RO', 'SK', 'SI', 'ES', 'SE',
 }
 EU_CURRENCIES = {
     'BG': 'BGN',
@@ -106,17 +114,21 @@ EU_CURRENCIES = {
     'RO': 'RON',
     'SE': 'SEK'
 }
+VAT_ID_COUNTRIES = EU_COUNTRIES | {'CH'}
 
 
 def is_eu_country(cc):
     cc = str(cc)
-    if cc == 'GB':
-        return now().astimezone(get_current_timezone()).year <= 2020
-    else:
-        return cc in EU_COUNTRIES
+    return cc in EU_COUNTRIES
+
+
+def ask_for_vat_id(cc):
+    cc = str(cc)
+    return cc in VAT_ID_COUNTRIES
 
 
 def cc_to_vat_prefix(country_code):
+    country_code = str(country_code)
     if country_code == 'GR':
         return 'EL'
     return country_code
@@ -124,8 +136,13 @@ def cc_to_vat_prefix(country_code):
 
 class TaxRule(LoggedModel):
     event = models.ForeignKey('Event', related_name='tax_rules', on_delete=models.CASCADE)
+    internal_name = models.CharField(
+        verbose_name=_('Internal name'),
+        max_length=190,
+        null=True, blank=True,
+    )
     name = I18nCharField(
-        verbose_name=_('Name'),
+        verbose_name=_('Official name'),
         help_text=_('Should be short, e.g. "VAT"'),
         max_length=190,
     )
@@ -138,6 +155,10 @@ class TaxRule(LoggedModel):
         verbose_name=_("The configured product prices include the tax amount"),
         default=True,
     )
+    keep_gross_if_rate_changes = models.BooleanField(
+        verbose_name=_("Keep gross amount constant if the tax rate changes based on the invoice address"),
+        default=False,
+    )
     eu_reverse_charge = models.BooleanField(
         verbose_name=_("Use EU reverse charge taxation rules"),
         default=False,
@@ -162,10 +183,13 @@ class TaxRule(LoggedModel):
         pass
 
     def allow_delete(self):
-        from pretix.base.models.orders import OrderFee, OrderPosition
+        from pretix.base.models.orders import (
+            OrderFee, OrderPosition, Transaction,
+        )
 
         return (
-            not OrderFee.objects.filter(tax_rule=self, order__event=self.event).exists()
+            not Transaction.objects.filter(tax_rule=self, order__event=self.event).exists()
+            and not OrderFee.objects.filter(tax_rule=self, order__event=self.event).exists()
             and not OrderPosition.all.filter(tax_rule=self, order__event=self.event).exists()
             and not self.event.items.filter(tax_rule=self).exists()
             and self.event.settings.tax_rate_default != self
@@ -192,6 +216,8 @@ class TaxRule(LoggedModel):
             s = _('plus {rate}% {name}').format(rate=self.rate, name=self.name)
         if self.eu_reverse_charge:
             s += ' ({})'.format(_('reverse charge enabled'))
+        if self.internal_name:
+            return f'{self.internal_name} ({s})'
         return str(s)
 
     @property
@@ -205,7 +231,7 @@ class TaxRule(LoggedModel):
             rule = self.get_matching_rule(invoice_address)
             if rule.get('action', 'vat') == 'block':
                 raise self.SaleNotAllowed()
-            if rule.get('action', 'vat') == 'vat' and rule.get('rate') is not None:
+            if rule.get('action', 'vat') in ('vat', 'require_approval') and rule.get('rate') is not None:
                 return Decimal(rule.get('rate'))
         return Decimal(self.rate)
 
@@ -222,13 +248,19 @@ class TaxRule(LoggedModel):
             rate = override_tax_rate
         elif invoice_address:
             adjust_rate = self.tax_rate_for(invoice_address)
-            if (adjust_rate == gross_price_is_tax_rate or force_fixed_gross_price) and base_price_is == 'gross':
+            if (adjust_rate == gross_price_is_tax_rate or force_fixed_gross_price or self.keep_gross_if_rate_changes) and base_price_is == 'gross':
                 rate = adjust_rate
             elif adjust_rate != rate:
-                normal_price = self.tax(base_price, base_price_is, currency, subtract_from_gross=subtract_from_gross)
-                base_price = normal_price.net
-                base_price_is = 'net'
-                subtract_from_gross = Decimal('0.00')
+                if self.keep_gross_if_rate_changes:
+                    normal_price = self.tax(base_price, base_price_is, currency, subtract_from_gross=subtract_from_gross)
+                    base_price = normal_price.gross
+                    base_price_is = 'gross'
+                    subtract_from_gross = Decimal('0.00')
+                else:
+                    normal_price = self.tax(base_price, base_price_is, currency, subtract_from_gross=subtract_from_gross)
+                    base_price = normal_price.net
+                    base_price_is = 'net'
+                    subtract_from_gross = Decimal('0.00')
                 rate = adjust_rate
 
         if rate == Decimal('0.00'):
@@ -331,12 +363,19 @@ class TaxRule(LoggedModel):
 
         return False
 
+    def _require_approval(self, invoice_address):
+        if self._custom_rules:
+            rule = self.get_matching_rule(invoice_address)
+            if rule.get('action', 'vat') == 'require_approval':
+                return True
+        return False
+
     def _tax_applicable(self, invoice_address):
         if self._custom_rules:
             rule = self.get_matching_rule(invoice_address)
             if rule.get('action', 'vat') == 'block':
                 raise self.SaleNotAllowed()
-            return rule.get('action', 'vat') == 'vat'
+            return rule.get('action', 'vat') in ('vat', 'require_approval')
 
         if not self.eu_reverse_charge:
             # No reverse charge rules? Always apply VAT!

src/pretix/base/payment.py

@@ -191,6 +191,15 @@ class BasePaymentProvider:
         """
         return self.verbose_name
 
+    @property
+    def confirm_button_name(self) -> str:
+        """
+        A label for the "confirm" button on the last page before a payment is started. This
+        is **not** used in the regular checkout flow, but only if the payment method is selected
+        for an existing order later on.
+        """
+        return _("Pay now")
+
     @property
     def identifier(self) -> str:
         """

src/pretix/base/reldate.py

@@ -273,6 +273,11 @@ class RelativeDateTimeField(forms.MultiValueField):
                 minutes_before=None
             ))
 
+    def has_changed(self, initial, data):
+        if initial is None:
+            initial = self.widget.decompress(initial)
+        return super().has_changed(initial, data)
+
     def clean(self, value):
         if value[0] == 'absolute' and not value[1]:
             raise ValidationError(self.error_messages['incomplete'])

src/pretix/base/services/cart.py

@@ -426,10 +426,10 @@ class CartManager:
                 if not cp.includes_tax:
                     price = self._get_price(cp.item, cp.variation, cp.voucher, cp.price, cp.subevent,
                                             cp_is_net=True, bundled_sum=bundled_sum)
-                    price = TaxedPrice(net=price.net, gross=price.net, rate=0, tax=0, name='')
+                    price = TaxedPrice(net=price.net, gross=price.net, rate=Decimal('0'), tax=Decimal('0'), name='')
                     pbv = self._get_price(cp.item, cp.variation, None, cp.price, cp.subevent,
                                           cp_is_net=True, bundled_sum=bundled_sum)
-                    pbv = TaxedPrice(net=pbv.net, gross=pbv.net, rate=0, tax=0, name='')
+                    pbv = TaxedPrice(net=pbv.net, gross=pbv.net, rate=Decimal('0'), tax=Decimal('0'), name='')
                 else:
                     price = self._get_price(cp.item, cp.variation, cp.voucher, cp.price, cp.subevent,
                                             bundled_sum=bundled_sum)
@@ -1106,10 +1106,11 @@ def update_tax_rates(event: Event, cart_id: str, invoice_address: InvoiceAddress
         rate = pos.item.tax_rule.tax_rate_for(invoice_address)
 
         if pos.tax_rate != rate:
-            current_net = pos.price - pos.tax_value
-            new_gross = pos.item.tax(current_net, base_price_is='net', invoice_address=invoice_address).gross
-            totaldiff += new_gross - pos.price
-            pos.price = new_gross
+            if not pos.item.tax_rule.keep_gross_if_rate_changes:
+                current_net = pos.price - pos.tax_value
+                new_gross = pos.item.tax(current_net, base_price_is='net', invoice_address=invoice_address).gross
+                totaldiff += new_gross - pos.price
+                pos.price = new_gross
             pos.includes_tax = rate != Decimal('0.00')
             pos.override_tax_rate = rate
             pos.save(update_fields=['price', 'includes_tax', 'override_tax_rate'])

src/pretix/base/services/checkin.py

@@ -373,22 +373,22 @@ class SQLLogic:
                 ).astimezone(pytz.UTC))
             elif values[0] == 'date_from':
                 return Coalesce(
-                    F(f'subevent__date_from'),
-                    F(f'order__event__date_from'),
+                    F('subevent__date_from'),
+                    F('order__event__date_from'),
                 )
             elif values[0] == 'date_to':
                 return Coalesce(
-                    F(f'subevent__date_to'),
-                    F(f'subevent__date_from'),
-                    F(f'order__event__date_to'),
-                    F(f'order__event__date_from'),
+                    F('subevent__date_to'),
+                    F('subevent__date_from'),
+                    F('order__event__date_to'),
+                    F('order__event__date_from'),
                 )
             elif values[0] == 'date_admission':
                 return Coalesce(
-                    F(f'subevent__date_admission'),
-                    F(f'subevent__date_from'),
-                    F(f'order__event__date_admission'),
-                    F(f'order__event__date_from'),
+                    F('subevent__date_admission'),
+                    F('subevent__date_from'),
+                    F('order__event__date_admission'),
+                    F('order__event__date_from'),
                 )
             else:
                 raise ValueError(f'Unknown time type {values[0]}')
@@ -736,7 +736,11 @@ def process_exit_all(sender, **kwargs):
         exit_all_at__isnull=False
     ).select_related('event', 'event__organizer')
     for cl in qs:
-        for p in cl.positions_inside:
+        positions = cl.positions_inside.filter(
+            Q(last_exit__isnull=True) | Q(last_exit__lte=cl.exit_all_at),
+            last_entry__lte=cl.exit_all_at,
+        )
+        for p in positions:
             with scope(organizer=cl.event.organizer):
                 ci = Checkin.objects.create(
                     position=p, list=cl, auto_checked_in=True, type=Checkin.TYPE_EXIT, datetime=cl.exit_all_at
@@ -748,6 +752,9 @@ def process_exit_all(sender, **kwargs):
             cl.event.settings.delete(f'autocheckin_dst_hack_{cl.pk}')
         try:
             cl.exit_all_at = make_aware(datetime.combine(d.date() + timedelta(days=1), d.time()), cl.event.timezone)
+        except pytz.exceptions.AmbiguousTimeError:
+            cl.exit_all_at = make_aware(datetime.combine(d.date() + timedelta(days=1), d.time()), cl.event.timezone,
+                                        is_dst=False)
         except pytz.exceptions.NonExistentTimeError:
             cl.event.settings.set(f'autocheckin_dst_hack_{cl.pk}', True)
             d += timedelta(hours=1)

src/pretix/base/services/export.py

@@ -56,6 +56,8 @@ def export(self, event: Event, fileid: str, provider: str, form_data: Dict[str,
     with language(event.settings.locale, event.settings.region), override(event.settings.timezone):
         responses = register_data_exporters.send(event)
         for receiver, response in responses:
+            if not response:
+                continue
             ex = response(event, event.organizer, set_progress)
             if ex.identifier == provider:
                 d = ex.render(form_data)

src/pretix/base/services/invoices.py

@@ -69,6 +69,10 @@ from pretix.helpers.models import modelcopy
 logger = logging.getLogger(__name__)
 
 
+def _location_oneliner(loc):
+    return ', '.join([l.strip() for l in loc.splitlines() if l and l.strip()])
+
+
 @transaction.atomic
 def build_invoice(invoice: Invoice) -> Invoice:
     invoice.locale = invoice.event.settings.get('invoice_language', invoice.event.settings.locale)
@@ -98,7 +102,7 @@ def build_invoice(invoice: Invoice) -> Invoice:
             payment = ""
         if invoice.event.settings.invoice_include_expire_date and invoice.order.status == Order.STATUS_PENDING:
             if payment:
-                payment += "<br />"
+                payment += "<br /><br />"
             payment += pgettext("invoice", "Please complete your payment before {expire_date}.").format(
                 expire_date=date_format(invoice.order.expires, "SHORT_DATE_FORMAT")
             )
@@ -176,19 +180,38 @@ def build_invoice(invoice: Invoice) -> Invoice:
         reverse_charge = False
 
         positions.sort(key=lambda p: p.sort_key)
+        fees = list(invoice.order.fees.all())
+
+        locations = {
+            str((p.subevent or invoice.event).location) if (p.subevent or invoice.event).location else None
+            for p in positions
+        }
+        if fees and invoice.event.has_subevents:
+            locations.add(None)
 
         tax_texts = []
+
+        if invoice.event.settings.invoice_event_location and len(locations) == 1 and list(locations)[0] is not None:
+            tax_texts.append(pgettext("invoice", "Event location: {location}").format(
+                location=_location_oneliner(str(list(locations)[0]))
+            ))
+
         for i, p in enumerate(positions):
             if not invoice.event.settings.invoice_include_free and p.price == Decimal('0.00') and not p.addon_c:
                 continue
 
+            location = str((p.subevent or invoice.event).location) if (p.subevent or invoice.event).location else None
+
             desc = str(p.item.name)
             if p.variation:
                 desc += " - " + str(p.variation.value)
             if p.addon_to_id:
                 desc = "  + " + desc
             if invoice.event.settings.invoice_attendee_name and p.attendee_name:
-                desc += "<br />" + pgettext("invoice", "Attendee: {name}").format(name=p.attendee_name)
+                desc += "<br />" + pgettext("invoice", "Attendee: {name}").format(
+                    name=p.attendee_name
+                )
+
             for recv, resp in invoice_line_text.send(sender=invoice.event, position=p):
                 if resp:
                     desc += "<br/>" + resp
@@ -204,6 +227,12 @@ def build_invoice(invoice: Invoice) -> Invoice:
 
             if invoice.event.has_subevents:
                 desc += "<br />" + pgettext("subevent", "Date: {}").format(p.subevent)
+
+            if invoice.event.settings.invoice_event_location and location and len(locations) > 1:
+                desc += "<br />" + pgettext("invoice", "Event location: {location}").format(
+                    location=_location_oneliner(location)
+                )
+
             InvoiceLine.objects.create(
                 position=i,
                 invoice=invoice,
@@ -216,6 +245,7 @@ def build_invoice(invoice: Invoice) -> Invoice:
                 attendee_name=p.attendee_name if invoice.event.settings.invoice_attendee_name else None,
                 event_date_from=p.subevent.date_from if invoice.event.has_subevents else invoice.event.date_from,
                 event_date_to=p.subevent.date_to if invoice.event.has_subevents else invoice.event.date_to,
+                event_location=location if invoice.event.settings.invoice_event_location else None,
                 tax_rate=p.tax_rate, tax_name=p.tax_rule.name if p.tax_rule else ''
             )
 
@@ -228,7 +258,7 @@ def build_invoice(invoice: Invoice) -> Invoice:
                     tax_texts.append(tax_text)
 
         offset = len(positions)
-        for i, fee in enumerate(invoice.order.fees.all()):
+        for i, fee in enumerate(fees):
             if fee.fee_type == OrderFee.FEE_TYPE_OTHER and fee.description:
                 fee_title = fee.description
             else:
@@ -242,6 +272,12 @@ def build_invoice(invoice: Invoice) -> Invoice:
                 gross_value=fee.value,
                 event_date_from=None if invoice.event.has_subevents else invoice.event.date_from,
                 event_date_to=None if invoice.event.has_subevents else invoice.event.date_to,
+                event_location=(
+                    None if invoice.event.has_subevents
+                    else (str(invoice.event.location)
+                          if invoice.event.settings.invoice_event_location and invoice.event.location
+                          else None)
+                ),
                 tax_value=fee.tax_value,
                 tax_rate=fee.tax_rate,
                 tax_name=fee.tax_rule.name if fee.tax_rule else '',
@@ -291,6 +327,7 @@ def generate_cancellation(invoice: Invoice, trigger_pdf=True):
     cancellation.payment_provider_text = ''
     cancellation.file = None
     cancellation.sent_to_organizer = None
+    cancellation.sent_to_customer = None
     with language(invoice.locale, invoice.event.settings.region):
         cancellation.invoice_from = invoice.event.settings.get('invoice_address_from')
         cancellation.invoice_from_name = invoice.event.settings.get('invoice_address_from_name')
@@ -346,8 +383,8 @@ def invoice_pdf_task(invoice: int):
             i.file.delete()
         with language(i.locale, i.event.settings.region):
             fname, ftype, fcontent = i.event.invoice_renderer.generate(i)
-            i.file.save(fname, ContentFile(fcontent))
-            i.save()
+            i.file.save(fname, ContentFile(fcontent), save=False)
+            i.save(update_fields=['file'])
             return i.file.name
 
 

src/pretix/base/services/mail.py

@@ -32,9 +32,10 @@
 # Unless required by applicable law or agreed to in writing, software distributed under the Apache License 2.0 is
 # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under the License.
-
+import hashlib
 import inspect
 import logging
+import mimetypes
 import os
 import re
 import smtplib
@@ -51,13 +52,14 @@ from bs4 import BeautifulSoup
 from celery import chain
 from celery.exceptions import MaxRetriesExceededError
 from django.conf import settings
+from django.core.files.storage import default_storage
 from django.core.mail import (
     EmailMultiAlternatives, SafeMIMEMultipart, get_connection,
 )
 from django.core.mail.message import SafeMIMEText
 from django.db import transaction
 from django.template.loader import get_template
-from django.utils.timezone import override
+from django.utils.timezone import now, override
 from django.utils.translation import gettext as _, pgettext
 from django_scopes import scope, scopes_disabled
 from i18nfield.strings import LazyI18nString
@@ -73,8 +75,9 @@ from pretix.base.services.tasks import TransactionAwareTask
 from pretix.base.services.tickets import get_tickets_for_order
 from pretix.base.signals import email_filter, global_email_filter
 from pretix.celery_app import app
+from pretix.helpers.hierarkey import clean_filename
 from pretix.multidomain.urlreverse import build_absolute_uri
-from pretix.presale.ical import get_ical
+from pretix.presale.ical import get_private_icals
 
 logger = logging.getLogger('pretix.base.mail')
 INVALID_ADDRESS = 'invalid-pretix-mail-address'
@@ -94,7 +97,7 @@ def mail(email: Union[str, Sequence[str]], subject: str, template: Union[str, La
          context: Dict[str, Any] = None, event: Event = None, locale: str = None, order: Order = None,
          position: OrderPosition = None, *, headers: dict = None, sender: str = None, organizer: Organizer = None,
          customer: Customer = None, invoices: Sequence = None, attach_tickets=False, auto_email=True, user=None,
-         attach_ical=False, attach_cached_files: Sequence = None):
+         attach_ical=False, attach_cached_files: Sequence = None, attach_other_files: list=None):
     """
     Sends out an email to a user. The mail will be sent synchronously or asynchronously depending on the installation.
 
@@ -142,6 +145,8 @@ def mail(email: Union[str, Sequence[str]], subject: str, template: Union[str, La
 
     :param attach_cached_files: A list of cached file to attach to this email.
 
+    :param attach_other_files: A list of file paths on our storage to attach.
+
     :raises MailOrderException: on obvious, immediate failures. Not raising an exception does not necessarily mean
         that the email has been sent, just that it has been queued by the email backend.
     """
@@ -212,7 +217,8 @@ def mail(email: Union[str, Sequence[str]], subject: str, template: Union[str, La
                 for bcc_mail in settings_holder.settings.mail_bcc.split(','):
                     bcc.append(bcc_mail.strip())
 
-            if settings_holder.settings.mail_from == settings.DEFAULT_FROM_EMAIL and settings_holder.settings.contact_mail and not headers.get('Reply-To'):
+            if settings_holder.settings.mail_from in (settings.DEFAULT_FROM_EMAIL, settings.MAIL_FROM_ORGANIZERS) \
+                    and settings_holder.settings.contact_mail and not headers.get('Reply-To'):
                 headers['Reply-To'] = settings_holder.settings.contact_mail
 
             prefix = settings_holder.settings.get('mail_prefix')
@@ -301,6 +307,7 @@ def mail(email: Union[str, Sequence[str]], subject: str, template: Union[str, La
             organizer=organizer.pk if organizer else None,
             customer=customer.pk if customer else None,
             attach_cached_files=[(cf.id if isinstance(cf, CachedFile) else cf) for cf in attach_cached_files] if attach_cached_files else [],
+            attach_other_files=attach_other_files,
         )
 
         if invoices:
@@ -338,7 +345,8 @@ class CustomEmail(EmailMultiAlternatives):
 def mail_send_task(self, *args, to: List[str], subject: str, body: str, html: str, sender: str,
                    event: int = None, position: int = None, headers: dict = None, bcc: List[str] = None,
                    invoices: List[int] = None, order: int = None, attach_tickets=False, user=None,
-                   organizer=None, customer=None, attach_ical=False, attach_cached_files: List[int] = None) -> bool:
+                   organizer=None, customer=None, attach_ical=False, attach_cached_files: List[int] = None,
+                   attach_other_files: List[str] = None) -> bool:
     email = CustomEmail(subject, body, sender, to=to, bcc=bcc, headers=headers)
     if html is not None:
         html_message = SafeMIMEMultipart(_subtype='related', encoding=settings.DEFAULT_CHARSET)
@@ -422,22 +430,12 @@ def mail_send_task(self, *args, to: List[str], subject: str, body: str, html: st
                                     }
                                 )
                         if attach_ical:
-                            ical_events = set()
-                            if event.has_subevents:
-                                if position:
-                                    ical_events.add(position.subevent)
-                                else:
-                                    for p in order.positions.all():
-                                        ical_events.add(p.subevent)
-                            else:
-                                ical_events.add(order.event)
-
-                            for i, e in enumerate(ical_events):
-                                cal = get_ical([e])
+                            for i, cal in enumerate(get_private_icals(event, [position] if position else order.positions.all())):
                                 email.attach('event-{}.ics'.format(i), cal.serialize(), 'text/calendar')
 
             email = email_filter.send_chained(event, 'message', message=email, order=order, user=user)
 
+        invoices_sent = []
         if invoices:
             invoices = Invoice.objects.filter(pk__in=invoices)
             for inv in invoices:
@@ -449,10 +447,25 @@ def mail_send_task(self, *args, to: List[str], subject: str, body: str, html: st
                                 inv.file.file.read(),
                                 'application/pdf'
                             )
+                        invoices_sent.append(inv)
                     except:
                         logger.exception('Could not attach invoice to email')
                         pass
 
+        if attach_other_files:
+            for fname in attach_other_files:
+                ftype, _ = mimetypes.guess_type(fname)
+                data = default_storage.open(fname).read()
+                try:
+                    email.attach(
+                        clean_filename(os.path.basename(fname)),
+                        data,
+                        ftype
+                    )
+                except:
+                    logger.exception('Could not attach file to email')
+                    pass
+
         if attach_cached_files:
             for cf in CachedFile.objects.filter(id__in=attach_cached_files):
                 if cf.file:
@@ -472,10 +485,30 @@ def mail_send_task(self, *args, to: List[str], subject: str, body: str, html: st
         try:
             backend.send_messages([email])
         except (smtplib.SMTPResponseException, smtplib.SMTPSenderRefused) as e:
-            if e.smtp_code in (101, 111, 421, 422, 431, 442, 447, 452):
-                # Most likely temporary, retry again (but pretty soon)
+            if e.smtp_code in (101, 111, 421, 422, 431, 432, 442, 447, 452):
+                if e.smtp_code == 432 and settings.HAS_REDIS:
+                    # This is likely Microsoft Exchange Online which has a pretty bad rate limit of max. 3 concurrent
+                    # SMTP connections which is *easily* exceeded with many celery threads. Just retrying with exponential
+                    # backoff won't be good enough if we have a lot of emails, instead we'll need to make sure our retry
+                    # intervals scatter such that the email won't all be retried at the same time again and cause the
+                    # same problem.
+                    # See also https://docs.microsoft.com/en-us/exchange/troubleshoot/send-emails/smtp-submission-improvements
+                    from django_redis import get_redis_connection
+
+                    redis_key = "pretix_mail_retry_" + hashlib.sha1(f"{getattr(backend, 'username', '_')}@{getattr(backend, 'host', '_')}".encode()).hexdigest()
+                    rc = get_redis_connection("redis")
+                    cnt = rc.incr(redis_key)
+                    rc.expire(redis_key, 300)
+
+                    max_retries = 10
+                    retry_after = 30 + cnt * 10
+                else:
+                    # Most likely some other kind of temporary failure, retry again (but pretty soon)
+                    max_retries = 5
+                    retry_after = 2 ** (self.request.retries * 3)  # max is 2 ** (4*3) = 4096 seconds = 68 minutes
+
                 try:
-                    self.retry(max_retries=5, countdown=2 ** (self.request.retries * 3))  # max is 2 ** (4*3) = 4096 seconds = 68 minutes
+                    self.retry(max_retries=max_retries, countdown=retry_after)
                 except MaxRetriesExceededError:
                     if log_target:
                         log_target.log_action(
@@ -546,7 +579,7 @@ def mail_send_task(self, *args, to: List[str], subject: str, body: str, html: st
                             }
                         )
                     raise e
-            if logger:
+            if log_target:
                 log_target.log_action(
                     'pretix.email.error',
                     data={
@@ -558,6 +591,10 @@ def mail_send_task(self, *args, to: List[str], subject: str, body: str, html: st
                 )
             logger.exception('Error sending email')
             raise SendMailException('Failed to send an email to {}.'.format(to))
+        else:
+            for i in invoices_sent:
+                i.sent_to_customer = now()
+                i.save(update_fields=['sent_to_customer'])
 
 
 def mail_send(*args, **kwargs):

src/pretix/base/services/notifications.py

@@ -148,7 +148,7 @@ def send_notification_mail(notification: Notification, user: User):
         ),
         'body': body_plain,
         'html': body_html,
-        'sender': settings.MAIL_FROM,
+        'sender': settings.MAIL_FROM_NOTIFICATIONS,
         'headers': {},
         'user': user.pk
     })

src/pretix/base/services/orderimport.py

@@ -33,6 +33,7 @@ from pretix.base.models import (
     CachedFile, Event, InvoiceAddress, Order, OrderPayment, OrderPosition,
     User,
 )
+from pretix.base.models.orders import Transaction
 from pretix.base.orderimport import get_all_columns
 from pretix.base.services.invoices import generate_invoice, invoice_qualified
 from pretix.base.services.tasks import ProfiledEventTask
@@ -146,6 +147,7 @@ def import_orders(event: Event, fileid: str, settings: dict, locale: str, user)
         # quota check?
         with event.lock():
             with transaction.atomic():
+                save_transactions = []
                 for o in orders:
                     o.total = sum([c.price for c in o._positions])  # currently no support for fees
                     if o.total == Decimal('0.00'):
@@ -187,6 +189,8 @@ def import_orders(event: Event, fileid: str, settings: dict, locale: str, user)
                         user=user,
                         data={'source': 'import'}
                     )
+                    save_transactions += o.create_transactions(is_new=True, fees=[], positions=o._positions, save=False)
+                Transaction.objects.bulk_create(save_transactions)
 
             for o in orders:
                 with language(o.locale, event.settings.region):

src/pretix/base/services/orders.py

@@ -35,7 +35,7 @@
 
 import json
 import logging
-from collections import Counter, namedtuple
+from collections import Counter, defaultdict, namedtuple
 from datetime import datetime, time, timedelta
 from decimal import Decimal
 from typing import List, Optional
@@ -46,7 +46,7 @@ from django.core.cache import cache
 from django.core.exceptions import ValidationError
 from django.db import transaction
 from django.db.models import (
-    Exists, F, IntegerField, Max, Min, OuterRef, Q, Sum, Value,
+    Count, Exists, F, IntegerField, Max, Min, OuterRef, Q, Sum, Value,
 )
 from django.db.models.functions import Coalesce, Greatest
 from django.db.transaction import get_connection
@@ -73,7 +73,7 @@ from pretix.base.models.orders import (
     InvoiceAddress, OrderFee, OrderRefund, generate_secret,
 )
 from pretix.base.models.organizer import TeamAPIToken
-from pretix.base.models.tax import TaxRule
+from pretix.base.models.tax import TAXED_ZERO, TaxedPrice, TaxRule
 from pretix.base.payment import BasePaymentProvider, PaymentException
 from pretix.base.reldate import RelativeDateWrapper
 from pretix.base.secrets import assign_ticket_secret
@@ -122,8 +122,7 @@ error_messages = {
                          'from your cart.'),
     'voucher_invalid_item': _('The voucher code used for one of the items in your cart is not valid for this item. We '
                               'removed this item from your cart.'),
-    'voucher_required': _('You need a valid voucher code to order one of the products in your cart. We removed this '
-                          'item from your cart.'),
+    'voucher_required': _('You need a valid voucher code to order one of the products.'),
     'some_subevent_not_started': _('The presale period for one of the events in your cart has not yet started. The '
                                    'affected positions have been removed from your cart.'),
     'some_subevent_ended': _('The presale period for one of the events in your cart has ended. The affected '
@@ -131,6 +130,13 @@ error_messages = {
     'seat_invalid': _('One of the seats in your order was invalid, we removed the position from your cart.'),
     'seat_unavailable': _('One of the seats in your order has been taken in the meantime, we removed the position from your cart.'),
     'country_blocked': _('One of the selected products is not available in the selected country.'),
+    'not_for_sale': _('You selected a product which is not available for sale.'),
+    'addon_invalid_base': _('You can not select an add-on for the selected product.'),
+    'addon_duplicate_item': _('You can not select two variations of the same add-on product.'),
+    'addon_max_count': _('You can select at most %(max)s add-ons from the category %(cat)s for the product %(base)s.'),
+    'addon_min_count': _('You need to select at least %(min)s add-ons from the category %(cat)s for the '
+                         'product %(base)s.'),
+    'addon_no_multi': _('You can select every add-ons from the category %(cat)s for the product %(base)s at most once.'),
 }
 
 logger = logging.getLogger(__name__)
@@ -181,6 +187,7 @@ def reactivate_order(order: Order, force: bool=False, user: User=None, auth=None
                     for m in position.granted_memberships.all():
                         m.canceled = False
                         m.save()
+                order.create_transactions()
         else:
             raise OrderError(is_available)
 
@@ -202,6 +209,7 @@ def extend_order(order: Order, new_date: datetime, force: bool=False, user: User
     if new_date < now():
         raise OrderError(_('The new expiry date needs to be in the future.'))
 
+    @transaction.atomic
     def change(was_expired=True):
         order.expires = new_date
         if was_expired:
@@ -221,6 +229,7 @@ def extend_order(order: Order, new_date: datetime, force: bool=False, user: User
             num_invoices = order.invoices.filter(is_cancellation=False).count()
             if num_invoices > 0 and order.invoices.filter(is_cancellation=True).count() >= num_invoices and invoice_qualified(order):
                 generate_invoice(order)
+            order.create_transactions()
 
     if order.status == Order.STATUS_PENDING:
         change(was_expired=False)
@@ -262,6 +271,7 @@ def mark_order_expired(order, user=None, auth=None):
         i = order.invoices.filter(is_cancellation=False).last()
         if i and not i.refered.exists():
             generate_cancellation(i)
+        order.create_transactions()
 
     order_expired.send(order.event, order=order)
     return order
@@ -280,6 +290,7 @@ def approve_order(order, user=None, send_mail: bool=True, auth=None, force=False
         order.require_approval = False
         order.set_expires(now(), order.event.subevents.filter(id__in=[p.subevent_id for p in order.positions.all()]))
         order.save(update_fields=['require_approval', 'expires'])
+        order.create_transactions()
 
         order.log_action('pretix.event.order.approved', user=user, auth=auth)
         if order.total == Decimal('0.00'):
@@ -352,6 +363,7 @@ def deny_order(order, comment='', user=None, send_mail: bool=True, auth=None):
         for position in order.positions.all():
             if position.voucher:
                 Voucher.objects.filter(pk=position.voucher.pk).update(redeemed=Greatest(0, F('redeemed') - 1))
+        order.create_transactions()
 
     order_denied.send(order.event, order=order)
 
@@ -472,6 +484,8 @@ def _cancel_order(order, user=None, send_mail: bool=True, api_token=None, device
                          data={'cancellation_fee': cancellation_fee})
         order.cancellation_requests.all().delete()
 
+        order.create_transactions()
+
         if send_mail:
             email_template = order.event.settings.mail_text_order_canceled
             with language(order.locale, order.event.settings.region):
@@ -686,7 +700,7 @@ def _check_positions(event: Event, now_dt: datetime, positions: List[CartPositio
                                 invoice_address=address, force_custom_price=True, max_discount=max_discount)
                 changed_prices[cp.pk] = bprice
             else:
-                bundled_sum = 0
+                bundled_sum = Decimal('0.00')
                 if not cp.addon_to_id:
                     for bundledp in cp.addons.all():
                         if bundledp.is_bundled:
@@ -842,7 +856,7 @@ def _create_order(event: Event, email: str, positions: List[CartPosition], now_d
             total=total,
             testmode=True if sales_channel.testmode_supported and event.testmode else False,
             meta_info=json.dumps(meta_info or {}),
-            require_approval=any(p.item.require_approval for p in positions),
+            require_approval=any(p.requires_approval(invoice_address=address) for p in positions),
             sales_channel=sales_channel.identifier,
             customer=customer,
         )
@@ -904,7 +918,8 @@ def _create_order(event: Event, email: str, positions: List[CartPosition], now_d
                 fee=pf
             )
 
-        OrderPosition.transform_cart_positions(positions, order)
+        orderpositions = OrderPosition.transform_cart_positions(positions, order)
+        order.create_transactions(positions=orderpositions, fees=fees, is_new=True)
         order.log_action('pretix.event.order.placed')
         if order.require_approval:
             order.log_action('pretix.event.order.placed.require_approval')
@@ -917,7 +932,7 @@ def _create_order(event: Event, email: str, positions: List[CartPosition], now_d
 
 
 def _order_placed_email(event: Event, order: Order, pprov: BasePaymentProvider, email_template, log_entry: str,
-                        invoice, payment: OrderPayment):
+                        invoice, payment: OrderPayment, is_free=False):
     email_context = get_email_context(event=event, order=order, payment=payment if pprov else None)
     email_subject = _('Your order: %(code)s') % {'code': order.code}
     try:
@@ -926,24 +941,29 @@ def _order_placed_email(event: Event, order: Order, pprov: BasePaymentProvider,
             log_entry,
             invoices=[invoice] if invoice and event.settings.invoice_email_attachment else [],
             attach_tickets=True,
-            attach_ical=event.settings.mail_attach_ical
+            attach_ical=event.settings.mail_attach_ical and (not event.settings.mail_attach_ical_paid_only or is_free),
+            attach_other_files=[a for a in [
+                event.settings.get('mail_attachment_new_order', as_type=str, default='')[len('file://'):]
+            ] if a],
         )
     except SendMailException:
         logger.exception('Order received email could not be sent')
 
 
-def _order_placed_email_attendee(event: Event, order: Order, position: OrderPosition, email_template, log_entry: str):
+def _order_placed_email_attendee(event: Event, order: Order, position: OrderPosition, email_template, log_entry: str, is_free=False):
     email_context = get_email_context(event=event, order=order, position=position)
     email_subject = _('Your event registration: %(code)s') % {'code': order.code}
 
     try:
-        order.send_mail(
+        position.send_mail(
             email_subject, email_template, email_context,
             log_entry,
             invoices=[],
             attach_tickets=True,
-            position=position,
-            attach_ical=event.settings.mail_attach_ical
+            attach_ical=event.settings.mail_attach_ical and (not event.settings.mail_attach_ical_paid_only or is_free),
+            attach_other_files=[a for a in [
+                event.settings.get('mail_attachment_new_order', as_type=str, default='')[len('file://'):]
+            ] if a],
         )
     except SendMailException:
         logger.exception('Order received email could not be sent to attendee')
@@ -1049,11 +1069,13 @@ def _perform_order(event: Event, payment_provider: str, position_ids: List[str],
             email_attendees_template = event.settings.mail_text_order_placed_attendee
 
         if sales_channel in event.settings.mail_sales_channel_placed_paid:
-            _order_placed_email(event, order, pprov, email_template, log_entry, invoice, payment)
+            _order_placed_email(event, order, pprov, email_template, log_entry, invoice, payment,
+                                is_free=free_order_flow)
             if email_attendees:
                 for p in order.positions.all():
                     if p.addon_to_id is None and p.attendee_email and p.attendee_email != order.email:
-                        _order_placed_email_attendee(event, order, p, email_attendees_template, log_entry)
+                        _order_placed_email_attendee(event, order, p, email_attendees_template, log_entry,
+                                                     is_free=free_order_flow)
 
     return order.id
 
@@ -1252,15 +1274,15 @@ class OrderChangeManager:
     ItemOperation = namedtuple('ItemOperation', ('position', 'item', 'variation'))
     SubeventOperation = namedtuple('SubeventOperation', ('position', 'subevent'))
     SeatOperation = namedtuple('SubeventOperation', ('position', 'seat'))
-    PriceOperation = namedtuple('PriceOperation', ('position', 'price'))
+    PriceOperation = namedtuple('PriceOperation', ('position', 'price', 'price_diff'))
     TaxRuleOperation = namedtuple('TaxRuleOperation', ('position', 'tax_rule'))
     MembershipOperation = namedtuple('MembershipOperation', ('position', 'membership'))
-    CancelOperation = namedtuple('CancelOperation', ('position',))
+    CancelOperation = namedtuple('CancelOperation', ('position', 'price_diff'))
     AddOperation = namedtuple('AddOperation', ('item', 'variation', 'price', 'addon_to', 'subevent', 'seat', 'membership'))
     SplitOperation = namedtuple('SplitOperation', ('position',))
-    FeeValueOperation = namedtuple('FeeValueOperation', ('fee', 'value'))
-    AddFeeOperation = namedtuple('AddFeeOperation', ('fee',))
-    CancelFeeOperation = namedtuple('CancelFeeOperation', ('fee',))
+    FeeValueOperation = namedtuple('FeeValueOperation', ('fee', 'value', 'price_diff'))
+    AddFeeOperation = namedtuple('AddFeeOperation', ('fee', 'price_diff'))
+    CancelFeeOperation = namedtuple('CancelFeeOperation', ('fee', 'price_diff'))
     RegenerateSecretOperation = namedtuple('RegenerateSecretOperation', ('position',))
 
     def __init__(self, order: Order, user=None, auth=None, notify=True, reissue_invoice=True):
@@ -1377,7 +1399,7 @@ class OrderChangeManager:
         if self.order.event.settings.invoice_include_free or price.gross != Decimal('0.00') or position.price != Decimal('0.00'):
             self._invoice_dirty = True
 
-        self._operations.append(self.PriceOperation(position, price))
+        self._operations.append(self.PriceOperation(position, price, price.gross - position.price))
 
     def change_tax_rule(self, position_or_fee, tax_rule: TaxRule):
         self._operations.append(self.TaxRuleOperation(position_or_fee, tax_rule))
@@ -1417,28 +1439,28 @@ class OrderChangeManager:
                     new_tax = tax_rule.tax(pos.price, base_price_is='gross', currency=self.event.currency,
                                            override_tax_rate=new_rate)
                 self._totaldiff += new_tax.gross - pos.price
-                self._operations.append(self.PriceOperation(pos, new_tax))
+                self._operations.append(self.PriceOperation(pos, new_tax, new_tax.gross - pos.price))
 
     def cancel_fee(self, fee: OrderFee):
         self._totaldiff -= fee.value
-        self._operations.append(self.CancelFeeOperation(fee))
+        self._operations.append(self.CancelFeeOperation(fee, -fee.value))
         self._invoice_dirty = True
 
     def add_fee(self, fee: OrderFee):
         self._totaldiff += fee.value
         self._invoice_dirty = True
-        self._operations.append(self.AddFeeOperation(fee))
+        self._operations.append(self.AddFeeOperation(fee, fee.value))
 
     def change_fee(self, fee: OrderFee, value: Decimal):
         value = (fee.tax_rule or TaxRule.zero()).tax(value, base_price_is='gross')
         self._totaldiff += value.gross - fee.value
         self._invoice_dirty = True
-        self._operations.append(self.FeeValueOperation(fee, value))
+        self._operations.append(self.FeeValueOperation(fee, value, value.gross - fee.value))
 
     def cancel(self, position: OrderPosition):
         self._totaldiff -= position.price
         self._quotadiff.subtract(position.quotas)
-        self._operations.append(self.CancelOperation(position))
+        self._operations.append(self.CancelOperation(position, -position.price))
         if position.seat:
             self._seatdiff.subtract([position.seat])
 
@@ -1463,7 +1485,7 @@ class OrderChangeManager:
         try:
             if price is None:
                 price = get_price(item, variation, subevent=subevent, invoice_address=self._invoice_address)
-            else:
+            elif not isinstance(price, TaxedPrice):
                 price = item.tax(price, base_price_is='gross', invoice_address=self._invoice_address)
         except TaxRule.SaleNotAllowed:
             raise OrderError(self.error_messages['tax_rule_country_blocked'])
@@ -1506,6 +1528,191 @@ class OrderChangeManager:
 
         self._operations.append(self.SplitOperation(position))
 
+    def set_addons(self, addons):
+        if self._operations:
+            raise ValueError("Setting addons should be the first/only operation")
+
+        # Prepare various containers to hold data later
+        current_addons = defaultdict(lambda: defaultdict(list))  # OrderPos -> currently attached add-ons
+        input_addons = defaultdict(Counter)  # OrderPos -> final desired set of add-ons
+        selected_addons = defaultdict(Counter)  # OrderPos, ItemAddOn -> final desired set of add-ons
+        opcache = {}  # OrderPos.pk -> OrderPos
+        quota_diff = Counter()  # Quota -> Number of usages
+        available_categories = defaultdict(set)  # OrderPos -> Category IDs to choose from
+        price_included = defaultdict(dict)  # OrderPos -> CategoryID -> bool(price is included)
+        toplevel_op = self.order.positions.filter(
+            addon_to__isnull=True
+        ).prefetch_related(
+            'addons', 'item__addons', 'item__addons__addon_category'
+        ).select_related('item', 'variation')
+
+        _items_cache = {
+            i.pk: i
+            for i in self.event.items.select_related('category').prefetch_related(
+                'addons', 'bundles', 'addons__addon_category', 'quotas'
+            ).annotate(
+                has_variations=Count('variations'),
+            ).filter(
+                id__in=[a['item'] for a in addons]
+            ).order_by()
+        }
+        _variations_cache = {
+            v.pk: v
+            for v in ItemVariation.objects.filter(item__event=self.event).prefetch_related(
+                'quotas'
+            ).select_related('item', 'item__event').filter(
+                id__in=[a['variation'] for a in addons if a.get('variation')]
+            ).order_by()
+        }
+
+        # Prefill some of the cache containers
+        for op in toplevel_op:
+            if op.canceled:
+                continue
+            available_categories[op.pk] = {iao.addon_category_id for iao in op.item.addons.all()}
+            price_included[op.pk] = {iao.addon_category_id: iao.price_included for iao in op.item.addons.all()}
+            opcache[op.pk] = op
+            for a in op.addons.all():
+                if a.canceled:
+                    continue
+
+                if not a.is_bundled:
+                    current_addons[op][a.item_id, a.variation_id].append(a)
+
+        # Create operations, perform various checks
+        for a in addons:
+            # Check whether the specified items are part of what we just fetched from the database
+            # If they are not, the user supplied item IDs which either do not exist or belong to
+            # a different event
+            if a['item'] not in _items_cache or (a['variation'] and a['variation'] not in _variations_cache):
+                raise OrderError(error_messages['not_for_sale'])
+
+            # Only attach addons to things that are actually in this user's cart
+            if a['addon_to'] not in opcache:
+                raise OrderError(error_messages['addon_invalid_base'])
+
+            op = opcache[a['addon_to']]
+            item = _items_cache[a['item']]
+            subevent = op.subevent  # for now, we might lift this requirement later
+            variation = _variations_cache[a['variation']] if a['variation'] is not None else None
+
+            if item.category_id not in available_categories[op.pk]:
+                raise OrderError(error_messages['addon_invalid_base'])
+
+            # Fetch all quotas. If there are no quotas, this item is not allowed to be sold.
+            quotas = list(item.quotas.filter(subevent=subevent)
+                          if variation is None else variation.quotas.filter(subevent=subevent))
+            if not quotas:
+                raise OrderError(error_messages['unavailable'])
+
+            if (a['item'], a['variation']) in input_addons[op.id]:
+                raise OrderError(error_messages['addon_duplicate_item'])
+
+            if item.require_voucher or item.hide_without_voucher or (variation and variation.hide_without_voucher):
+                raise OrderError(error_messages['voucher_required'])
+
+            if not item.is_available() or (variation and not variation.is_available()):
+                raise OrderError(error_messages['unavailable'])
+
+            if self.order.sales_channel not in item.sales_channels or (
+                    variation and self.order.sales_channel not in variation.sales_channels):
+                raise OrderError(error_messages['unavailable'])
+
+            if subevent and item.pk in subevent.item_overrides and not subevent.item_overrides[item.pk].is_available():
+                raise OrderError(error_messages['not_for_sale'])
+
+            if subevent and variation and variation.pk in subevent.var_overrides and \
+                    not subevent.var_overrides[variation.pk].is_available():
+                raise OrderError(error_messages['not_for_sale'])
+
+            if item.has_variations and not variation:
+                raise OrderError(error_messages['not_for_sale'])
+
+            if variation and variation.item_id != item.pk:
+                raise OrderError(error_messages['not_for_sale'])
+
+            if subevent and subevent.presale_start and now() < subevent.presale_start:
+                raise OrderError(error_messages['not_started'])
+
+            if (subevent and subevent.presale_has_ended) or self.event.presale_has_ended:
+                raise OrderError(error_messages['ended'])
+
+            if item.require_bundling:
+                raise OrderError(error_messages['unavailable'])
+
+            input_addons[op.id][a['item'], a['variation']] = a.get('count', 1)
+            selected_addons[op.id, item.category_id][a['item'], a['variation']] = a.get('count', 1)
+
+            if price_included[op.pk].get(item.category_id):
+                price = TAXED_ZERO
+            else:
+                price = get_price(
+                    item, variation, voucher=None, custom_price=a.get('price'), subevent=op.subevent,
+                    custom_price_is_net=self.event.settings.display_net_prices,
+                    invoice_address=self._invoice_address,
+                )
+
+            if a.get('count', 1) > len(current_addons[op][a['item'], a['variation']]):
+                # This add-on is new, add it to the cart
+                for quota in quotas:
+                    quota_diff[quota] += a.get('count', 1) - len(current_addons[op][a['item'], a['variation']])
+
+                for i in range(a.get('count', 1) - len(current_addons[op][a['item'], a['variation']])):
+                    self.add_position(
+                        item=item, variation=variation, price=price,
+                        addon_to=op, subevent=op.subevent, seat=None,
+                    )
+
+        # Check constraints on the add-on combinations
+        for op in toplevel_op:
+            item = op.item
+            for iao in item.addons.all():
+                selected = selected_addons[op.id, iao.addon_category_id]
+                n_per_i = Counter()
+                for (i, v), c in selected.items():
+                    n_per_i[i] += c
+                if sum(selected.values()) > iao.max_count:
+                    # TODO: Proper i18n
+                    # TODO: Proper pluralization
+                    raise OrderError(
+                        error_messages['addon_max_count'],
+                        {
+                            'base': str(item.name),
+                            'max': iao.max_count,
+                            'cat': str(iao.addon_category.name),
+                        }
+                    )
+                elif sum(selected.values()) < iao.min_count:
+                    # TODO: Proper i18n
+                    # TODO: Proper pluralization
+                    raise OrderError(
+                        error_messages['addon_min_count'],
+                        {
+                            'base': str(item.name),
+                            'min': iao.min_count,
+                            'cat': str(iao.addon_category.name),
+                        }
+                    )
+                elif any(v > 1 for v in n_per_i.values()) and not iao.multi_allowed:
+                    raise OrderError(
+                        error_messages['addon_no_multi'],
+                        {
+                            'base': str(item.name),
+                            'cat': str(iao.addon_category.name),
+                        }
+                    )
+
+        # Detect removed add-ons and create RemoveOperations
+        for cp, al in list(current_addons.items()):
+            for k, v in al.items():
+                input_num = input_addons[cp.id].get(k, 0)
+                current_num = len(current_addons[cp].get(k, []))
+                if input_num < current_num:
+                    for a in current_addons[cp][k][:current_num - input_num]:
+                        if a.canceled:
+                            continue
+                        self.cancel(a)
+
     def _check_seats(self):
         for seat, diff in self._seatdiff.items():
             if diff <= 0:
@@ -1552,17 +1759,16 @@ class OrderChangeManager:
                 self.order.save()
             elif self.open_payment:
                 try:
-                    with transaction.atomic():
-                        self.open_payment.payment_provider.cancel_payment(self.open_payment)
-                        self.order.log_action(
-                            'pretix.event.order.payment.canceled',
-                            {
-                                'local_id': self.open_payment.local_id,
-                                'provider': self.open_payment.provider,
-                            },
-                            user=self.user,
-                            auth=self.auth
-                        )
+                    self.open_payment.payment_provider.cancel_payment(self.open_payment)
+                    self.order.log_action(
+                        'pretix.event.order.payment.canceled',
+                        {
+                            'local_id': self.open_payment.local_id,
+                            'provider': self.open_payment.provider,
+                        },
+                        user=self.user,
+                        auth=self.auth
+                    )
                 except PaymentException as e:
                     self.order.log_action(
                         'pretix.event.order.payment.canceled.failed',
@@ -1577,12 +1783,11 @@ class OrderChangeManager:
         elif self.order.status in (Order.STATUS_PENDING, Order.STATUS_EXPIRED) and self._totaldiff > 0:
             if self.open_payment:
                 try:
-                    with transaction.atomic():
-                        self.open_payment.payment_provider.cancel_payment(self.open_payment)
-                        self.order.log_action('pretix.event.order.payment.canceled', {
-                            'local_id': self.open_payment.local_id,
-                            'provider': self.open_payment.provider,
-                        }, user=self.user, auth=self.auth)
+                    self.open_payment.payment_provider.cancel_payment(self.open_payment)
+                    self.order.log_action('pretix.event.order.payment.canceled', {
+                        'local_id': self.open_payment.local_id,
+                        'provider': self.open_payment.provider,
+                    }, user=self.user, auth=self.auth)
                 except PaymentException as e:
                     self.order.log_action(
                         'pretix.event.order.payment.canceled.failed',
@@ -1868,7 +2073,7 @@ class OrderChangeManager:
         split_order.code = None
         split_order.datetime = now()
         split_order.secret = generate_secret()
-        split_order.require_approval = self.order.require_approval and any(p.item.require_approval for p in split_positions)
+        split_order.require_approval = self.order.require_approval and any(p.requires_approval(invoice_address=self._invoice_address) for p in split_positions)
         split_order.save()
         split_order.log_action('pretix.event.order.changed.split_from', user=self.user, auth=self.auth, data={
             'original_order': self.order.code
@@ -2120,12 +2325,15 @@ class OrderChangeManager:
                 except TaxRule.SaleNotAllowed:
                     raise OrderError(self.error_messages['tax_rule_country_blocked'])
             self._recalculate_total_and_payment_fee()
+            self._check_paid_price_change()
+            self._check_paid_to_free()
             if self.order.status in (Order.STATUS_PENDING, Order.STATUS_PAID):
                 self._reissue_invoice()
             self._clear_tickets_cache()
             self.order.touch()
-        self._check_paid_price_change()
-        self._check_paid_to_free()
+            self.order.create_transactions()
+            if self.split_order:
+                self.split_order.create_transactions()
 
         if self.notify:
             notify_user_changed_order(
@@ -2399,6 +2607,7 @@ def change_payment_provider(order: Order, payment_provider, amount=None, new_pay
             generate_cancellation(i)
             generate_invoice(order)
 
+    order.create_transactions()
     return old_fee, new_fee, fee, new_payment
 
 

src/pretix/base/services/quotas.py

@@ -113,10 +113,8 @@ class QuotaAvailability:
         be a few minutes outdated. In this case, you may not rely on the results in the ``count_*`` properties.
         """
         now_dt = now_dt or now()
-        quotas = list(set(self._queue))
-        quotas_original = list(self._queue)
-        self._queue.clear()
-        if not quotas:
+        quota_ids_set = {q.id for q in self._queue}
+        if not quota_ids_set:
             return
 
         if allow_cache:
@@ -129,7 +127,7 @@ class QuotaAvailability:
             elif settings.HAS_REDIS:
                 rc = get_redis_connection("redis")
                 quotas_by_event = defaultdict(list)
-                for q in quotas_original:
+                for q in [_q for _q in self._queue if _q.id in quota_ids_set]:
                     quotas_by_event[q.event_id].append(q)
 
                 for eventid, evquotas in quotas_by_event.items():
@@ -139,16 +137,19 @@ class QuotaAvailability:
                             data = [rv for rv in redisval.decode().split(',')]
                             # Except for some rare situations, we don't want to use cache entries older than 2 minutes
                             if time.time() - int(data[2]) < 120 or allow_cache_stale:
-                                quotas_original.remove(q)
-                                quotas.remove(q)
+                                quota_ids_set.remove(q.id)
                                 if data[1] == "None":
                                     self.results[q] = int(data[0]), None
                                 else:
                                     self.results[q] = int(data[0]), int(data[1])
 
-        if not quotas:
+        if not quota_ids_set:
             return
 
+        quotas = [_q for _q in self._queue if _q.id in quota_ids_set]
+        quotas_original = list(quotas)
+        self._queue.clear()
+
         self._compute(quotas, now_dt)
 
         for q in quotas_original:
@@ -284,15 +285,16 @@ class QuotaAvailability:
         seq = Q(subevent_id__in=subevents)
         if None in subevents:
             seq |= Q(subevent__isnull=True)
+        quota_ids = {q.pk for q in quotas}
         op_lookup = OrderPosition.objects.filter(
             order__status__in=[Order.STATUS_PAID, Order.STATUS_PENDING],
             order__event_id__in=events,
         ).filter(seq).filter(
             Q(
                 Q(variation_id__isnull=True) &
-                Q(item_id__in={i['item_id'] for i in q_items if self._quota_objects[i['quota_id']] in quotas})
+                Q(item_id__in={i['item_id'] for i in q_items if i['quota_id'] in quota_ids})
             ) | Q(
-                variation_id__in={i['itemvariation_id'] for i in q_vars if self._quota_objects[i['quota_id']] in quotas})
+                variation_id__in={i['itemvariation_id'] for i in q_vars if i['quota_id'] in quota_ids})
         ).order_by()
         if any(q.release_after_exit for q in quotas):
             op_lookup = op_lookup.annotate(
@@ -359,6 +361,7 @@ class QuotaAvailability:
             func = 'GREATEST'
 
         subevents = {q.subevent_id for q in quotas}
+        quota_ids = {q.pk for q in quotas}
         seq = Q(subevent_id__in=subevents)
         if None in subevents:
             seq |= Q(subevent__isnull=True)
@@ -370,10 +373,9 @@ class QuotaAvailability:
             Q(
                 Q(
                     Q(variation_id__isnull=True) &
-                    Q(item_id__in={i['item_id'] for i in q_items if self._quota_objects[i['quota_id']] in quotas})
+                    Q(item_id__in={i['item_id'] for i in q_items if i['quota_id'] in quota_ids})
                 ) | Q(
-                    variation_id__in={i['itemvariation_id'] for i in q_vars if
-                                      self._quota_objects[i['quota_id']] in quotas}
+                    variation_id__in={i['itemvariation_id'] for i in q_vars if i['quota_id'] in quota_ids}
                 ) | Q(
                     quota_id__in=[q.pk for q in quotas]
                 )
@@ -398,6 +400,7 @@ class QuotaAvailability:
     def _compute_carts(self, quotas, q_items, q_vars, size_left, now_dt):
         events = {q.event_id for q in quotas}
         subevents = {q.subevent_id for q in quotas}
+        quota_ids = {q.pk for q in quotas}
         seq = Q(subevent_id__in=subevents)
         if None in subevents:
             seq |= Q(subevent__isnull=True)
@@ -413,9 +416,9 @@ class QuotaAvailability:
             Q(
                 Q(
                     Q(variation_id__isnull=True) &
-                    Q(item_id__in={i['item_id'] for i in q_items if self._quota_objects[i['quota_id']] in quotas})
+                    Q(item_id__in={i['item_id'] for i in q_items if i['quota_id'] in quota_ids})
                 ) | Q(
-                    variation_id__in={i['itemvariation_id'] for i in q_vars if self._quota_objects[i['quota_id']] in quotas}
+                    variation_id__in={i['itemvariation_id'] for i in q_vars if i['quota_id'] in quota_ids}
                 )
             )
         ).order_by().values('item_id', 'subevent_id', 'variation_id').annotate(c=Count('*'))
@@ -434,6 +437,7 @@ class QuotaAvailability:
     def _compute_waitinglist(self, quotas, q_items, q_vars, size_left):
         events = {q.event_id for q in quotas}
         subevents = {q.subevent_id for q in quotas}
+        quota_ids = {q.pk for q in quotas}
         seq = Q(subevent_id__in=subevents)
         if None in subevents:
             seq |= Q(subevent__isnull=True)
@@ -444,9 +448,8 @@ class QuotaAvailability:
             Q(
                 Q(
                     Q(variation_id__isnull=True) &
-                    Q(item_id__in={i['item_id'] for i in q_items if self._quota_objects[i['quota_id']] in quotas})
-                ) | Q(variation_id__in={i['itemvariation_id'] for i in q_vars if
-                                        self._quota_objects[i['quota_id']] in quotas})
+                    Q(item_id__in={i['item_id'] for i in q_items if i['quota_id'] in quota_ids})
+                ) | Q(variation_id__in={i['itemvariation_id'] for i in q_vars if i['quota_id'] in quota_ids})
             )
         ).order_by().values('item_id', 'subevent_id', 'variation_id').annotate(c=Count('*'))
         for line in w_lookup:

src/pretix/base/services/seating.py

@@ -45,7 +45,7 @@ def validate_plan_change(event, subevent, plan):
                 seat=OuterRef('pk'),
                 canceled=False,
             ).exclude(
-                order__status=(Order.STATUS_CANCELED, Order.STATUS_EXPIRED)
+                order__status__in=(Order.STATUS_CANCELED, Order.STATUS_EXPIRED)
             ))
         ).annotate(has_v=Count('vouchers')).filter(
             subevent=subevent,
@@ -69,7 +69,7 @@ def generate_seats(event, subevent, plan, mapping, blocked_guids=None):
             seat=OuterRef('pk'),
             canceled=False,
         ).exclude(
-            order__status=Order.STATUS_CANCELED
+            order__status__in=(Order.STATUS_CANCELED, Order.STATUS_EXPIRED)
         )),
         has_v=Count('vouchers')
     ).filter(subevent=subevent).order_by():
@@ -134,7 +134,7 @@ def generate_seats(event, subevent, plan, mapping, blocked_guids=None):
     Seat.objects.bulk_create(create_seats)
     CartPosition.objects.filter(seat__in=[s.pk for s in current_seats.values()]).delete()
     OrderPosition.all.filter(
-        Q(canceled=True) | Q(order__status=Order.STATUS_CANCELED),
+        Q(canceled=True) | Q(order__status__in=(Order.STATUS_CANCELED, Order.STATUS_EXPIRED)),
         seat__in=[s.pk for s in current_seats.values()],
     ).update(seat=None)
     Seat.objects.filter(pk__in=[s.pk for s in current_seats.values()]).delete()

src/pretix/base/services/tax.py

@@ -0,0 +1,134 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+import logging
+import os
+import re
+from urllib.error import HTTPError
+
+import vat_moss.errors
+import vat_moss.id
+from django.conf import settings
+from django.utils.translation import gettext_lazy as _
+from zeep import Client, Transport
+from zeep.cache import SqliteCache
+from zeep.exceptions import Fault
+
+from pretix.base.models.tax import cc_to_vat_prefix, is_eu_country
+
+logger = logging.getLogger(__name__)
+
+
+class VATIDError(Exception):
+    def __init__(self, message):
+        self.message = message
+
+
+class VATIDFinalError(VATIDError):
+    pass
+
+
+class VATIDTemporaryError(VATIDError):
+    pass
+
+
+def _validate_vat_id_EU(vat_id, country_code):
+    if vat_id[:2] != cc_to_vat_prefix(country_code):
+        raise VATIDFinalError(_('Your VAT ID does not match the selected country.'))
+
+    try:
+        result = vat_moss.id.validate(vat_id)
+        if result:
+            country_code, normalized_id, company_name = result
+            return normalized_id
+    except (vat_moss.errors.InvalidError, ValueError):
+        raise VATIDFinalError(_('This VAT ID is not valid. Please re-check your input.'))
+    except vat_moss.errors.WebServiceUnavailableError:
+        logger.exception('VAT ID checking failed for country {}'.format(country_code))
+        raise VATIDTemporaryError(_(
+            'Your VAT ID could not be checked, as the VAT checking service of '
+            'your country is currently not available. We will therefore '
+            'need to charge VAT on your invoice. You can get the tax amount '
+            'back via the VAT reimbursement process.'
+        ))
+    except (vat_moss.errors.WebServiceError, HTTPError):
+        logger.exception('VAT ID checking failed for country {}'.format(country_code))
+        raise VATIDTemporaryError(_(
+            'Your VAT ID could not be checked, as the VAT checking service of '
+            'your country returned an incorrect result. We will therefore '
+            'need to charge VAT on your invoice. Please contact support to '
+            'resolve this manually.'
+        ))
+
+
+def _validate_vat_id_CH(vat_id, country_code):
+    if vat_id[:3] != 'CHE':
+        raise VATIDFinalError(_('Your VAT ID does not match the selected country.'))
+
+    vat_id = re.sub('[^A-Z0-9]', '', vat_id.replace('HR', '').replace('MWST', ''))
+    try:
+        transport = Transport(cache=SqliteCache(os.path.join(settings.CACHE_DIR, "validate_vat_id_ch_zeep_cache.db")))
+        client = Client(
+            'https://www.uid-wse.admin.ch/V5.0/PublicServices.svc?wsdl',
+            transport=transport
+        )
+        result = client.service.ValidateUID(uid=vat_id)
+    except Fault as e:
+        if e.message == 'Data_validation_failed':
+            raise VATIDFinalError(_('This VAT ID is not valid. Please re-check your input.'))
+        elif e.message == 'Request_limit_exceeded':
+            logger.exception('VAT ID checking failed for country {} due to request limit'.format(country_code))
+            raise VATIDTemporaryError(_(
+                'Your VAT ID could not be checked, as the VAT checking service of '
+                'your country returned an incorrect result. We will therefore '
+                'need to charge VAT on your invoice. Please contact support to '
+                'resolve this manually.'
+            ))
+        else:
+            logger.exception('VAT ID checking failed for country {}'.format(country_code))
+            raise VATIDTemporaryError(_(
+                'Your VAT ID could not be checked, as the VAT checking service of '
+                'your country returned an incorrect result. We will therefore '
+                'need to charge VAT on your invoice. Please contact support to '
+                'resolve this manually.'
+            ))
+    except:
+        logger.exception('VAT ID checking failed for country {}'.format(country_code))
+        raise VATIDTemporaryError(_(
+            'Your VAT ID could not be checked, as the VAT checking service of '
+            'your country is currently not available. We will therefore '
+            'need to charge VAT on your invoice. You can get the tax amount '
+            'back via the VAT reimbursement process.'
+        ))
+    else:
+        if not result:
+            raise VATIDFinalError(_('This VAT ID is not valid. Please re-check your input.'))
+        return vat_id
+
+
+def validate_vat_id(vat_id, country_code):
+    country_code = str(country_code)
+    if is_eu_country(country_code):
+        return _validate_vat_id_EU(vat_id, country_code)
+    elif country_code == 'CH':
+        return _validate_vat_id_CH(vat_id, country_code)
+
+    raise VATIDTemporaryError(f'VAT ID should not be entered for country {country_code}')

src/pretix/base/settings.py

@@ -48,10 +48,12 @@ from django.core.validators import (
     MaxValueValidator, MinValueValidator, RegexValidator,
 )
 from django.db.models import Model
+from django.utils.functional import lazy
 from django.utils.text import format_lazy
 from django.utils.translation import (
-    gettext_lazy as _, gettext_noop, pgettext, pgettext_lazy,
+    gettext, gettext_lazy as _, gettext_noop, pgettext, pgettext_lazy,
 )
+from django_countries.fields import Country
 from hierarkey.models import GlobalSettingsBase, Hierarkey
 from i18nfield.forms import I18nFormField, I18nTextarea, I18nTextInput
 from i18nfield.strings import LazyI18nString
@@ -61,7 +63,7 @@ from pretix.api.serializers.fields import (
     ListMultipleChoiceField, UploadedFileField,
 )
 from pretix.api.serializers.i18n import I18nField
-from pretix.base.models.tax import TaxRule
+from pretix.base.models.tax import VAT_ID_COUNTRIES, TaxRule
 from pretix.base.reldate import (
     RelativeDateField, RelativeDateTimeField, RelativeDateWrapper,
     SerializerRelativeDateField, SerializerRelativeDateTimeField,
@@ -92,6 +94,25 @@ def primary_font_kwargs():
     }
 
 
+def restricted_plugin_kwargs():
+    from pretix.base.plugins import get_all_plugins
+
+    plugins_available = [
+        (p.module, p.name) for p in get_all_plugins(None)
+        if (
+            not p.name.startswith('.') and
+            getattr(p, 'visible', True) and
+            getattr(p, 'restricted', False) and
+            not hasattr(p, 'is_available')  # this means you should not really use restricted and is_available
+        )
+    ]
+    return {
+        'widget': forms.CheckboxSelectMultiple,
+        'label': _("Allow usage of restricted plugins"),
+        'choices': plugins_available,
+    }
+
+
 class LazyI18nStringList(UserList):
     def __init__(self, init_list=None):
         super().__init__()
@@ -107,6 +128,13 @@ class LazyI18nStringList(UserList):
 
 
 DEFAULTS = {
+    'allowed_restricted_plugins': {
+        'default': [],
+        'type': list,
+        'form_class': forms.MultipleChoiceField,
+        'serializer_class': serializers.MultipleChoiceField,
+        'form_kwargs': lambda: restricted_plugin_kwargs(),
+    },
     'customer_accounts': {
         'default': 'False',
         'type': bool,
@@ -134,11 +162,15 @@ DEFAULTS = {
         'type': int,
         'form_class': forms.IntegerField,
         'serializer_class': serializers.IntegerField,
+        'serializer_kwargs': dict(
+            min_value=1,
+        ),
         'form_kwargs': dict(
             min_value=1,
+            required=True,
             label=_("Maximum number of items per order"),
             help_text=_("Add-on products will not be counted.")
-        )
+        ),
     },
     'display_net_prices': {
         'default': 'False',
@@ -308,6 +340,17 @@ DEFAULTS = {
             label=_("Show attendee names on invoices"),
         )
     },
+    'invoice_event_location': {
+        'default': 'False',
+        'type': bool,
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Show event location on invoices"),
+            help_text=_("The event location will be shown below the list of products if it is the same for all "
+                        "lines. It will be shown on every line if there are different locations.")
+        )
+    },
     'invoice_eu_currencies': {
         'default': 'True',
         'type': bool,
@@ -355,11 +398,12 @@ DEFAULTS = {
         'form_class': I18nFormField,
         'serializer_class': I18nField,
         'form_kwargs': dict(
-            label=_("Custom address field"),
+            label=_("Custom recipient field"),
             widget=I18nTextInput,
             help_text=_("If you want to add a custom text field, e.g. for a country-specific registration number, to "
                         "your invoice address form, please fill in the label here. This label will both be used for "
-                        "asking the user to input their details as well as for displaying the value on the invoice. "
+                        "asking the user to input their details as well as for displaying the value on the invoice. It will "
+                        "be shown on the invoice below the headline. "
                         "The field will not be required.")
         )
     },
@@ -370,7 +414,11 @@ DEFAULTS = {
         'serializer_class': serializers.BooleanField,
         'form_kwargs': dict(
             label=_("Ask for VAT ID"),
-            help_text=_("Does only work if an invoice address is asked for. VAT ID is not required."),
+            help_text=format_lazy(
+                _("Only works if an invoice address is asked for. VAT ID is never required and only requested from "
+                  "business customers in the following countries: {countries}"),
+                countries=lazy(lambda *args: ', '.join(sorted(gettext(Country(cc).name) for cc in VAT_ID_COUNTRIES)), str)()
+            ),
             widget=forms.CheckboxInput(attrs={'data-checkbox-dependency': '#id_invoice_address_asked'}),
         )
     },
@@ -409,7 +457,7 @@ DEFAULTS = {
         )
     },
     'invoice_include_expire_date': {
-        'default': 'False',
+        'default': 'False',  # default for new events is True
         'type': bool,
         'form_class': forms.BooleanField,
         'serializer_class': serializers.BooleanField,
@@ -423,9 +471,11 @@ DEFAULTS = {
         'type': int,
         'form_class': forms.IntegerField,
         'serializer_class': serializers.IntegerField,
+        'serializer_kwargs': dict(),
         'form_kwargs': dict(
             label=_("Minimum length of invoice number after prefix"),
             help_text=_("The part of your invoice number after your prefix will be filled up with leading zeros up to this length, e.g. INV-001 or INV-00001."),
+            required=True,
         )
     },
     'invoice_numbers_consecutive': {
@@ -465,7 +515,7 @@ DEFAULTS = {
         )
     },
     'invoice_renderer': {
-        'default': 'classic',
+        'default': 'classic',  # default for new events is 'modern1'
         'type': str,
     },
     'ticket_secret_generator': {
@@ -489,6 +539,7 @@ DEFAULTS = {
                 MinValueValidator(12),
                 MaxValueValidator(64),
             ],
+            required=True,
             widget=forms.NumberInput(
                 attrs={
                     'min': '12',
@@ -503,9 +554,13 @@ DEFAULTS = {
         'type': int,
         'form_class': forms.IntegerField,
         'serializer_class': serializers.IntegerField,
+        'serializer_kwargs': dict(
+            min_value=0,
+        ),
         'form_kwargs': dict(
             min_value=0,
             label=_("Reservation period"),
+            required=True,
             help_text=_("The number of minutes the items in a user's cart are reserved for this user."),
         )
     },
@@ -560,6 +615,7 @@ DEFAULTS = {
         'form_kwargs': dict(
             label=_("Set payment term"),
             widget=forms.RadioSelect,
+            required=True,
             choices=(
                 ('days', _("in days")),
                 ('minutes', _("in minutes"))
@@ -891,7 +947,7 @@ DEFAULTS = {
         'type': str
     },
     'invoice_email_attachment': {
-        'default': 'False',
+        'default': 'False',  # default for new events is True
         'type': bool,
         'form_class': forms.BooleanField,
         'serializer_class': serializers.BooleanField,
@@ -1074,9 +1130,13 @@ DEFAULTS = {
         'type': int,
         'serializer_class': serializers.IntegerField,
         'form_class': forms.IntegerField,
+        'serializer_kwargs': dict(
+            min_value=1,
+        ),
         'form_kwargs': dict(
             label=_("Waiting list response time"),
             min_value=1,
+            required=True,
             help_text=_("If a ticket voucher is sent to a person on the waiting list, it has to be redeemed within this "
                         "number of hours until it expires and can be re-assigned to the next person on the list."),
             widget=forms.NumberInput(),
@@ -1224,7 +1284,7 @@ DEFAULTS = {
         )
     },
     'event_list_type': {
-        'default': 'list',
+        'default': 'list',  # default for new events is 'calendar'
         'type': str,
         'form_class': forms.ChoiceField,
         'serializer_class': serializers.ChoiceField,
@@ -1284,6 +1344,15 @@ DEFAULTS = {
             label=_("Customers can change the variation of the products they purchased"),
         )
     },
+    'change_allow_user_addons': {
+        'default': 'False',
+        'type': bool,
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Customers can change their selected add-on products"),
+        )
+    },
     'change_allow_user_price': {
         'default': 'gte',
         'type': str,
@@ -1486,6 +1555,17 @@ DEFAULTS = {
         ),
         'serializer_class': serializers.URLField,
     },
+    'privacy_url': {
+        'default': None,
+        'type': str,
+        'form_class': forms.URLField,
+        'form_kwargs': dict(
+            label=_("Privacy Policy URL"),
+            help_text=_("This should point e.g. to a part of your website that explains how you use data gathered in "
+                        "your ticket shop."),
+        ),
+        'serializer_class': serializers.URLField,
+    },
     'confirm_texts': {
         'default': LazyI18nStringList(),
         'type': LazyI18nStringList,
@@ -1519,6 +1599,32 @@ DEFAULTS = {
             help_text=_("If enabled, we will attach an .ics calendar file to order confirmation emails."),
         )
     },
+    'mail_attach_ical_paid_only': {
+        'default': 'False',
+        'type': bool,
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Attach calendar files only after order has been paid"),
+            help_text=_("Use this if you e.g. put a private access link into the calendar file to make sure people only "
+                        "receive it after their payment was confirmed."),
+        )
+    },
+    'mail_attach_ical_description': {
+        'default': '',
+        'type': LazyI18nString,
+        'form_class': I18nFormField,
+        'form_kwargs': dict(
+            label=_("Event description"),
+            widget=I18nTextarea,
+            help_text=_(
+                "You can use this to share information with your attendees, such as travel information or the link to a digital event. "
+                "If you keep it empty, we will put a link to the event shop, the admission time, and your organizer name in there. "
+                "We do not allow using placeholders with sensitive person-specific data as calendar entries are often shared with an "
+                "unspecified number of people."
+            ),
+        )
+    },
     'mail_prefix': {
         'default': None,
         'type': str,
@@ -1535,7 +1641,7 @@ DEFAULTS = {
         'type': str
     },
     'mail_from': {
-        'default': settings.MAIL_FROM,
+        'default': settings.MAIL_FROM_ORGANIZERS,
         'type': str,
         'form_class': forms.EmailField,
         'serializer_class': serializers.EmailField,
@@ -1650,6 +1756,30 @@ You can change your order details and view the status of your order at
 Best regards,
 Your {event} team"""))
     },
+    'mail_attachment_new_order': {
+        'default': None,
+        'type': File,
+        'form_class': ExtFileField,
+        'form_kwargs': dict(
+            label=_('Attachment for new orders'),
+            ext_whitelist=(".pdf",),
+            max_size=settings.FILE_UPLOAD_MAX_SIZE_EMAIL_AUTO_ATTACHMENT,
+            help_text=_('This file will be attached to the first email that we send for every new order. Therefore it will be '
+                        'combined with the "Placed order", "Free order", or "Received order" texts from above. It will be sent '
+                        'to both order contacts and attendees. You can use this e.g. to send your terms of service. Do not use '
+                        'it to send non-public information as this file might be sent before payment is confirmed or the order '
+                        'is approved. To avoid this vital email going to spam, you can only upload PDF files of up to {size} MB.').format(
+                size=settings.FILE_UPLOAD_MAX_SIZE_EMAIL_AUTO_ATTACHMENT // (1024 * 1024),
+            )
+        ),
+        'serializer_class': UploadedFileField,
+        'serializer_kwargs': dict(
+            allowed_types=[
+                'application/pdf'
+            ],
+            max_size=settings.FILE_UPLOAD_MAX_SIZE_EMAIL_AUTO_ATTACHMENT,
+        )
+    },
     'mail_send_order_placed_attendee': {
         'type': bool,
         'default': 'False'
@@ -1709,6 +1839,17 @@ Best regards,
 Your {event} team"""))
     },
     'mail_days_order_expire_warning': {
+        'form_class': forms.IntegerField,
+        'serializer_class': serializers.IntegerField,
+        'serializer_kwargs': dict(
+            min_value=0,
+        ),
+        'form_kwargs': dict(
+            label=_("Number of days"),
+            min_value=0,
+            help_text=_("This email will be sent out this many days before the order expires. If the "
+                        "value is 0, the mail will never be sent.")
+        ),
         'type': int,
         'default': '3'
     },
@@ -1957,7 +2098,7 @@ Your {organizer} team"""))
         ),
     },
     'theme_color_success': {
-        'default': '#50A167',
+        'default': '#50a167',
         'type': str,
         'form_class': forms.CharField,
         'serializer_class': serializers.CharField,
@@ -1979,7 +2120,7 @@ Your {organizer} team"""))
         ),
     },
     'theme_color_danger': {
-        'default': '#C44F4F',
+        'default': '#c44f4f',
         'type': str,
         'form_class': forms.CharField,
         'serializer_class': serializers.CharField,
@@ -2001,7 +2142,7 @@ Your {organizer} team"""))
         ),
     },
     'theme_color_background': {
-        'default': '#FFFFFF',
+        'default': '#f5f5f5',
         'type': str,
         'form_class': forms.CharField,
         'serializer_class': serializers.CharField,
@@ -2427,7 +2568,7 @@ Your {organizer} team"""))
         )
     },
     'name_scheme': {
-        'default': 'full',
+        'default': 'full',  # default for new events is 'given_family'
         'type': str
     },
     'giftcard_length': {
@@ -2452,6 +2593,77 @@ Your {organizer} team"""))
                         'many years. If you keep it empty, gift cards do not have an explicit expiry date.'),
         )
     },
+    'cookie_consent': {
+        'default': 'False',
+        'form_class': forms.BooleanField,
+        'serializer_class': serializers.BooleanField,
+        'form_kwargs': dict(
+            label=_("Enable cookie consent management features"),
+        ),
+        'type': bool,
+    },
+    'cookie_consent_dialog_text': {
+        'default': LazyI18nString.from_gettext(gettext_noop(
+            'By clicking "Accept all cookies", you agree to the storing of cookies and use of similar technologies on '
+            'your device.'
+        )),
+        'type': LazyI18nString,
+        'serializer_class': I18nField,
+        'form_class': I18nFormField,
+        'form_kwargs': dict(
+            label=_("Dialog text"),
+            widget=I18nTextarea,
+            widget_kwargs={'attrs': {'rows': '3', 'data-display-dependency': '#id_settings-cookie_consent'}},
+        )
+    },
+    'cookie_consent_dialog_text_secondary': {
+        'default': LazyI18nString.from_gettext(gettext_noop(
+            'We use cookies and similar technologies to gather data that allows us to improve this website and our '
+            'offerings. If you do not agree, we will only use cookies if they are essential to providing the services '
+            'this website offers.'
+        )),
+        'type': LazyI18nString,
+        'serializer_class': I18nField,
+        'form_class': I18nFormField,
+        'form_kwargs': dict(
+            label=_("Secondary dialog text"),
+            widget=I18nTextarea,
+            widget_kwargs={'attrs': {'rows': '3', 'data-display-dependency': '#id_settings-cookie_consent'}},
+        )
+    },
+    'cookie_consent_dialog_title': {
+        'default': LazyI18nString.from_gettext(gettext_noop('Privacy settings')),
+        'type': LazyI18nString,
+        'serializer_class': I18nField,
+        'form_class': I18nFormField,
+        'form_kwargs': dict(
+            label=_('Dialog title'),
+            widget=I18nTextInput,
+            widget_kwargs={'attrs': {'data-display-dependency': '#id_settings-cookie_consent'}},
+        )
+    },
+    'cookie_consent_dialog_button_yes': {
+        'default': LazyI18nString.from_gettext(gettext_noop('Accept all cookies')),
+        'type': LazyI18nString,
+        'serializer_class': I18nField,
+        'form_class': I18nFormField,
+        'form_kwargs': dict(
+            label=_('"Accept" button description'),
+            widget=I18nTextInput,
+            widget_kwargs={'attrs': {'data-display-dependency': '#id_settings-cookie_consent'}},
+        )
+    },
+    'cookie_consent_dialog_button_no': {
+        'default': LazyI18nString.from_gettext(gettext_noop('Required cookies only')),
+        'type': LazyI18nString,
+        'serializer_class': I18nField,
+        'form_class': I18nFormField,
+        'form_kwargs': dict(
+            label=_('"Reject" button description'),
+            widget=I18nTextInput,
+            widget_kwargs={'attrs': {'data-display-dependency': '#id_settings-cookie_consent'}},
+        )
+    },
     'seating_choice': {
         'default': 'True',
         'form_class': forms.BooleanField,

src/pretix/base/shredder.py

@@ -34,7 +34,6 @@
 
 import json
 import os
-from datetime import timedelta
 from typing import List, Tuple
 
 from django.db import transaction
@@ -70,11 +69,11 @@ def shred_constraints(event: Event):
             max_fromto=Greatest(Max('date_to'), Max('date_from'))
         )
         max_date = max_date['max_fromto'] or max_date['max_to'] or max_date['max_from']
-        if max_date is not None and max_date > now() - timedelta(days=30):
-            return _('Your event needs to be over for at least 30 days to use this feature.')
+        if max_date is not None and max_date >= now():
+            return _('Your event needs to be over to use this feature.')
     else:
-        if (event.date_to or event.date_from) > now() - timedelta(days=30):
-            return _('Your event needs to be over for at least 30 days to use this feature.')
+        if (event.date_to or event.date_from) >= now():
+            return _('Your event needs to be over to use this feature.')
     if event.live:
         return _('Your ticket shop needs to be offline to use this feature.')
     return None