Upgrade to Django 3.0 and other dependencies (#1568)

* Upgrade Django to 3.0 and other dependencies to recent versions

* Fix otp version contsraint

* Remove six dependency

* Resolve some warnings

* Fix failing tests

* Update django-countries

* Resolve all RemovedInDjango31Warnings in test suite

* Run isort

* Fix import

* Update PostgreSQL version on travis

src/pretix/base/models/auth.py

@@ -14,7 +14,7 @@ from django.db import models
 from django.db.models import Q
 from django.utils.crypto import get_random_string, salted_hmac
 from django.utils.timezone import now
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 from django_otp.models import Device
 from django_scopes import scopes_disabled
 from u2flib_server.utils import (

src/pretix/base/models/checkin.py

@@ -1,7 +1,7 @@
 from django.db import models
 from django.db.models import Exists, OuterRef
 from django.utils.timezone import now
-from django.utils.translation import pgettext_lazy, ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _, pgettext_lazy
 from django_scopes import ScopedManager
 
 from pretix.base.models import LoggedModel

src/pretix/base/models/devices.py

@@ -3,7 +3,7 @@ import string
 from django.db import models
 from django.db.models import Max
 from django.utils.crypto import get_random_string
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 from django_scopes import ScopedManager, scopes_disabled
 
 from pretix.base.models import LoggedModel

src/pretix/base/models/event.py

@@ -17,7 +17,7 @@ from django.template.defaultfilters import date as _date
 from django.utils.crypto import get_random_string
 from django.utils.functional import cached_property
 from django.utils.timezone import make_aware, now
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 from django_scopes import ScopedManager, scopes_disabled
 from i18nfield.fields import I18nCharField, I18nTextField
 

src/pretix/base/models/giftcards.py

@@ -5,7 +5,7 @@ from django.core.validators import RegexValidator
 from django.db import models
 from django.db.models import Sum
 from django.utils.crypto import get_random_string
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 
 from pretix.base.banlist import banned
 from pretix.base.models import LoggedModel
@@ -83,6 +83,7 @@ class GiftCard(LoggedModel):
 
     class Meta:
         unique_together = (('secret', 'issuer'),)
+        ordering = ("issuance",)
 
 
 class GiftCardTransaction(models.Model):

src/pretix/base/models/items.py

@@ -16,7 +16,7 @@ from django.utils import formats
 from django.utils.crypto import get_random_string
 from django.utils.functional import cached_property
 from django.utils.timezone import is_naive, make_aware, now
-from django.utils.translation import pgettext_lazy, ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _, pgettext_lazy
 from django_countries.fields import Country
 from django_scopes import ScopedManager
 from i18nfield.fields import I18nCharField, I18nTextField

src/pretix/base/models/log.py

@@ -6,7 +6,7 @@ from django.db import models
 from django.urls import reverse
 from django.utils.functional import cached_property
 from django.utils.html import escape
-from django.utils.translation import pgettext_lazy, ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _, pgettext_lazy
 
 from pretix.base.signals import logentry_object_link
 

src/pretix/base/models/notifications.py

@@ -1,5 +1,5 @@
 from django.db import models
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 
 
 class NotificationSetting(models.Model):

src/pretix/base/models/orders.py

@@ -26,7 +26,7 @@ from django.utils.encoding import escape_uri_path
 from django.utils.formats import date_format
 from django.utils.functional import cached_property
 from django.utils.timezone import make_aware, now
-from django.utils.translation import pgettext_lazy, ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _, pgettext_lazy
 from django_countries.fields import Country, CountryField
 from django_scopes import ScopedManager, scopes_disabled
 from i18nfield.strings import LazyI18nString

src/pretix/base/models/organizer.py

@@ -5,7 +5,7 @@ from django.db import models
 from django.db.models import Exists, OuterRef, Q
 from django.utils.crypto import get_random_string
 from django.utils.functional import cached_property
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 
 from pretix.base.models.base import LoggedModel
 from pretix.base.validators import OrganizerSlugBanlistValidator

src/pretix/base/models/seating.py

@@ -8,7 +8,7 @@ from django.db import models
 from django.db.models import F, Q
 from django.utils.deconstruct import deconstructible
 from django.utils.timezone import now
-from django.utils.translation import gettext, ugettext_lazy as _
+from django.utils.translation import gettext, gettext_lazy as _
 
 from pretix.base.models import Event, Item, LoggedModel, Organizer, SubEvent
 

src/pretix/base/models/tax.py

@@ -4,7 +4,7 @@ from decimal import Decimal
 from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils.formats import localize
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _
 from django_countries.fields import CountryField
 from i18nfield.fields import I18nCharField
 

src/pretix/base/models/vouchers.py

@@ -8,7 +8,7 @@ from django.db.models import F, OuterRef, Q, Subquery, Sum
 from django.db.models.functions import Coalesce
 from django.utils.crypto import get_random_string
 from django.utils.timezone import now
-from django.utils.translation import pgettext_lazy, ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _, pgettext_lazy
 from django_scopes import ScopedManager, scopes_disabled
 
 from pretix.base.banlist import banned

src/pretix/base/models/waitinglist.py

@@ -3,7 +3,7 @@ from datetime import timedelta
 from django.core.exceptions import ValidationError
 from django.db import models, transaction
 from django.utils.timezone import now
-from django.utils.translation import pgettext_lazy, ugettext_lazy as _
+from django.utils.translation import gettext_lazy as _, pgettext_lazy
 from django_scopes import ScopedManager
 
 from pretix.base.email import get_email_context