Do not issue invoices for free payments

src/pretix/base/payment.py

@@ -431,7 +431,7 @@ class FreeOrderProvider(BasePaymentProvider):
     def payment_perform(self, request: HttpRequest, order: Order):
         from pretix.base.services.orders import mark_order_paid
         try:
-            mark_order_paid(order, 'free')
+            mark_order_paid(order, 'free', send_mail=False)
         except Quota.QuotaExceededException as e:
             messages.error(request, str(e))
 

src/pretix/base/services/invoices.py

@@ -325,6 +325,12 @@ def invoice_pdf(invoice: int):
         return i.file.name
 
 
+def invoice_qualified(order: Order):
+    if order.total == Decimal('0.00'):
+        return False
+    return True
+
+
 if settings.HAS_CELERY:
     from pretix.celery import app
 

src/pretix/base/services/orders.py

@@ -1,4 +1,5 @@
 from datetime import datetime, timedelta
+from decimal import Decimal
 
 from django.conf import settings
 from django.db import transaction
@@ -16,7 +17,7 @@ from pretix.base.models import (
 from pretix.base.models.orders import InvoiceAddress
 from pretix.base.payment import BasePaymentProvider
 from pretix.base.services.invoices import (
-    generate_cancellation, generate_invoice,
+    generate_cancellation, generate_invoice, invoice_qualified,
 )
 from pretix.base.services.mail import mail
 from pretix.base.signals import (
@@ -46,7 +47,7 @@ error_messages = {
 
 
 def mark_order_paid(order: Order, provider: str=None, info: str=None, date: datetime=None, manual: bool=None,
-                    force: bool=False, user: User=None) -> Order:
+                    force: bool=False, send_mail: bool=True, user: User=None) -> Order:
     """
     Marks an order as paid. This sets the payment provider, info and date and returns
     the order object.
@@ -61,6 +62,8 @@ def mark_order_paid(order: Order, provider: str=None, info: str=None, date: date
     :param force: Whether this payment should be marked as paid even if no remaining
                   quota is available (default: ``False``).
     :type force: boolean
+    :param send_mail: Whether an email should be sent to the user about this event (default: ``True``).
+    :type send_mail: boolean
     :param user: The user that performed the change
     :raises Quota.QuotaExceededException: if the quota is exceeded and ``force`` is ``False``
     """
@@ -85,20 +88,21 @@ def mark_order_paid(order: Order, provider: str=None, info: str=None, date: date
     }, user=user)
     order_paid.send(order.event, order=order)
 
-    with language(order.locale):
+    if send_mail:
-        mail(
+        with language(order.locale):
-            order.email, _('Payment received for your order: %(code)s') % {'code': order.code},
+            mail(
-            order.event.settings.mail_text_order_paid,
+                order.email, _('Payment received for your order: %(code)s') % {'code': order.code},
-            {
+                order.event.settings.mail_text_order_paid,
-                'event': order.event.name,
+                {
-                'url': build_absolute_uri(order.event, 'presale:event.order', kwargs={
+                    'event': order.event.name,
-                    'order': order.code,
+                    'url': build_absolute_uri(order.event, 'presale:event.order', kwargs={
-                    'secret': order.secret
+                        'order': order.code,
-                }),
+                        'secret': order.secret
-                'downloads': order.event.settings.get('ticket_download', as_type=bool)
+                    }),
-            },
+                    'downloads': order.event.settings.get('ticket_download', as_type=bool)
-            order.event, locale=order.locale
+                },
-        )
+                order.event, locale=order.locale
+            )
     return order
 
 
@@ -289,13 +293,17 @@ def _perform_order(event: str, payment_provider: str, position_ids: List[str],
         except InvoiceAddress.DoesNotExist:
             pass
 
-    if event.settings.get('invoice_generate') == 'True':
+    if event.settings.get('invoice_generate') == 'True' and invoice_qualified(order):
         generate_invoice(order)
 
     with language(order.locale):
+        if order.total == Decimal('0.00'):
+            mailtext = event.settings.mail_text_order_free
+        else:
+            mailtext = event.settings.mail_text_order_placed
         mail(
             order.email, _('Your order: %(code)s') % {'code': order.code},
-            event.settings.mail_text_order_placed,
+            mailtext,
             {
                 'total': LazyNumber(order.total),
                 'currency': event.currency,

src/pretix/base/settings.py

@@ -147,6 +147,19 @@ to your order for {event}.
 You can change your order details and view the status of your order at
 {url}
 
+Best regards,
+Your {event} team"""))
+    },
+    'mail_text_order_free': {
+        'type': LazyI18nString,
+        'default': LazyI18nString.from_gettext(ugettext_noop("""Hello,
+
+we successfully received your order for {event}. As you only ordered
+free products, no payment is required.
+
+You can change your order details and view the status of your order at
+{url}
+
 Best regards,
 Your {event} team"""))
     },

src/pretix/control/forms/event.py

@@ -298,6 +298,12 @@ class MailSettingsForm(SettingsForm):
         widget=I18nTextarea,
         help_text=_("Available placeholders: {event}, {url}")
     )
+    mail_text_order_free = I18nFormField(
+        label=_("Free order"),
+        required=False,
+        widget=I18nTextarea,
+        help_text=_("Available placeholders: {event}, {url}")
+    )
     mail_text_resend_link = I18nFormField(
         label=_("Resend link"),
         required=False,

src/pretix/control/templates/pretixcontrol/order/index.html

@@ -110,7 +110,7 @@
                                     {% endif %}
                                 {% endfor %}
                             </dd>
-                        {% elif request.event.settings.invoice_generate == 'admin' or request.event.settings.invoice_generate == 'user' %}
+                        {% elif can_generate_invoice %}
                             <dt>{% trans "Invoices" %}</dt>
                             <dd>
                                 <form class="form-inline helper-display-inline" method="post"

src/pretix/control/views/orders.py

@@ -17,7 +17,9 @@ from pretix.base.models import (
 )
 from pretix.base.services import tickets
 from pretix.base.services.export import export
-from pretix.base.services.invoices import generate_invoice, invoice_pdf
+from pretix.base.services.invoices import (
+    generate_invoice, invoice_pdf, invoice_qualified,
+)
 from pretix.base.services.mail import mail
 from pretix.base.services.orders import cancel_order, mark_order_paid
 from pretix.base.services.stats import order_overview
@@ -75,6 +77,14 @@ class OrderView(EventPermissionRequiredMixin, DetailView):
     def order(self):
         return self.get_object()
 
+    def get_context_data(self, **kwargs):
+        ctx = super().get_context_data(**kwargs)
+        ctx['can_generate_invoice'] = invoice_qualified(self.order) and (
+            self.request.event.settings.invoice_generate == 'admin' or
+            self.request.event.settings.invoice_generate == 'user'
+        )
+        return ctx
+
     @cached_property
     def payment_provider(self):
         responses = register_payment_providers.send(self.request.event)
@@ -212,7 +222,8 @@ class OrderInvoiceCreate(OrderView):
     permission = 'can_change_orders'
 
     def post(self, *args, **kwargs):
-        if self.request.event.settings.get('invoice_generate') not in ('admin', 'user'):
+        if self.request.event.settings.get('invoice_generate') not in ('admin', 'user') or not invoice_qualified(
+                self.order):
             messages.error(self.request, _('You cannot generate an invoice for this order.'))
         elif self.order.invoices.exists():
             messages.error(self.request, _('An invoice for this order already exists.'))

src/pretix/presale/templates/pretixpresale/event/order.html

@@ -12,6 +12,8 @@
             <h2>{% trans "Thank you!" %}</h2>
             {% if order.status != 'p' %}
                 <p>{% trans "Your order has been placed successfully. See below for details." %}</p>
+            {% elif order.total == 0 %}
+                <p>{% trans "Your order has been processed successfully! See below for details." %}</p>
             {% else %}
                 <p>{% trans "We successfully received your payment. See below for details." %}</p>
             {% endif %}
@@ -118,7 +120,7 @@
                     </div>
                 </div>
             </div>
-        {% elif request.event.settings.invoice_generate == 'user' %}
+        {% elif can_generate_invoice %}
             <div class="col-xs-12 {% if request.event.settings.invoice_address_asked %}col-md-6{% endif %}">
                 <div class="panel panel-primary">
                     <div class="panel-heading">
@@ -139,7 +141,7 @@
             </div>
         {% endif %}
         {% if request.event.settings.invoice_address_asked %}
-            <div class="col-xs-12 {% if invoices or request.event.settings.invoice_generate == 'user' %}col-md-6{% endif %}">
+            <div class="col-xs-12 {% if invoices or can_generate_invoice %}col-md-6{% endif %}">
                 <div class="panel panel-primary">
                     <div class="panel-heading">
                         {% if order.can_modify_answers %}

src/pretix/presale/views/order.py

@@ -13,7 +13,9 @@ from pretix.base.models import (
     CachedFile, CachedTicket, Invoice, Order, OrderPosition,
 )
 from pretix.base.models.orders import InvoiceAddress
-from pretix.base.services.invoices import generate_invoice, invoice_pdf
+from pretix.base.services.invoices import (
+    generate_invoice, invoice_pdf, invoice_qualified,
+)
 from pretix.base.services.orders import OrderError, cancel_order
 from pretix.base.services.tickets import generate
 from pretix.base.signals import (
@@ -91,6 +93,10 @@ class OrderDetails(EventViewMixin, OrderDetailMixin, CartMixin, TemplateView):
             payment_fee=self.order.payment_fee, payment_fee_tax_rate=self.order.payment_fee_tax_rate
         )
         ctx['invoices'] = list(self.order.invoices.all())
+        ctx['can_generate_invoice'] = invoice_qualified(self.order) and (
+            self.request.event.settings.invoice_generate == 'user'
+        )
+
         if self.order.status == Order.STATUS_PENDING:
             ctx['payment'] = self.payment_provider.order_pending_render(self.request, self.order)
             ctx['can_retry'] = (
@@ -155,7 +161,7 @@ class OrderInvoiceCreate(EventViewMixin, OrderDetailMixin, View):
         return super().dispatch(request, *args, **kwargs)
 
     def post(self, request, *args, **kwargs):
-        if self.request.event.settings.get('invoice_generate') != 'user':
+        if self.request.event.settings.get('invoice_generate') != 'user' or not invoice_qualified(self.order):
             messages.error(self.request, _('You cannot generate an invoice for this order.'))
         elif self.order.invoices.exists():
             messages.error(self.request, _('An invoice for this order already exists.'))