django-upgrade 1.12.0

Versioned blocks

Removes outdated comparisons and blocks from if statements comparing to django.VERSION. Supports comparisons of the form:

if django.VERSION <comparator> (<X>, <Y>):
    ...

Where <comparator> is one of <, <= , >, or >=, and <X> and <Y> are integer literals. A single else block may be present, but elif is not supported.

-if django.VERSION < (4, 1):
-    class RenameIndex:
-        ...

-if django.VERSION >= (4, 1):
-    constraint.validate()
-else:
-    custom_validation(constraint)
+constraint.validate()

See also pyupgrade’s similar feature that removes outdated code from checks on the Python version.

Admin model registration

Rewrites admin.site.register() calls to the new @admin.register() decorator syntax when eligible. This only applies in files that use from django.contrib import admin or from django.contrib.gis import admin.

 from django.contrib import admin

+@admin.register(MyModel1, MyModel2)
 class MyCustomAdmin(admin.ModelAdmin):
     ...

-admin.site.register(MyModel1, MyCustomAdmin)
-admin.site.register(MyModel2, MyCustomAdmin)

This also works with custom admin sites. Such calls are detected heuristically based on three criteria:

1. The object whose register() method is called has a name ending with site.

2. The registered class has a name ending with Admin.

3. The filename has the word admin somewhere in its path.

from myapp.admin import custom_site
from django.contrib import admin

+@admin.register(MyModel)
+@admin.register(MyModel, site=custom_site)
class MyModelAdmin(admin.ModelAdmin):
    pass

-custom_site.register(MyModel, MyModelAdmin)
-admin.site.register(MyModel, MyModelAdmin)

If a register() call is preceded by an unregister() call that includes the same model, it is ignored.

from django.contrib import admin


class MyCustomAdmin(admin.ModelAdmin):
    ...


admin.site.unregister(MyModel1)
admin.site.register(MyModel1, MyCustomAdmin)

on_delete argument

Add on_delete=models.CASCADE to ForeignKey and OneToOneField:

 from django.db import models

-models.ForeignKey("auth.User")
+models.ForeignKey("auth.User", on_delete=models.CASCADE)

-models.OneToOneField("auth.User")
+models.OneToOneField("auth.User", on_delete=models.CASCADE)

This fixer also support from-imports:

-from django.db.models import ForeignKey
+from django.db.models import CASCADE, ForeignKey

-ForeignKey("auth.User")
+ForeignKey("auth.User", on_delete=CASCADE)

DATABASES

Update the DATABASES setting backend path django.db.backends.postgresql_psycopg2 to use the renamed version django.db.backends.postgresql.

Settings files are heuristically detected as modules with the whole word “settings” somewhere in their path. For example myproject/settings.py or myproject/settings/production.py.

 DATABASES = {
     "default": {
-        "ENGINE": "django.db.backends.postgresql_psycopg2",
+        "ENGINE": "django.db.backends.postgresql",
         "NAME": "mydatabase",
         "USER": "mydatabaseuser",
         "PASSWORD": "mypassword",
         "HOST": "127.0.0.1",
         "PORT": "5432",
     }
 }

Compatibility imports

Rewrites some compatibility imports:

• django.forms.utils.pretty_name in django.forms.forms

• django.forms.boundfield.BoundField in django.forms.forms

Whilst mentioned in the Django 3.1 release notes, these have been possible since Django 1.9.

-from django.forms.forms import pretty_name
+from django.forms.utils import pretty_name

Compatibility imports

Rewrites some compatibility imports:

• django.core.exceptions.EmptyResultSet in django.db.models.query, django.db.models.sql, and django.db.models.sql.datastructures

• django.core.exceptions.FieldDoesNotExist in django.db.models.fields

Whilst mentioned in the Django 3.1 release notes, these have been possible since Django 1.11.

-from django.db.models.query import EmptyResultSet
+from django.core.exceptions import EmptyResultSet

-from django.db.models.fields import FieldDoesNotExist
+from django.core.exceptions import FieldDoesNotExist

URL’s

Rewrites imports of include() and url() from django.conf.urls to django.urls. url() calls using compatible regexes are rewritten to the new path() syntax, otherwise they are converted to call re_path().

-from django.conf.urls import include, url
+from django.urls import include, path, re_path

 urlpatterns = [
-    url(r'^$', views.index, name='index'),
+    path('', views.index, name='index'),
-    url(r'^about/$', views.about, name='about'),
+    path('about/', views.about, name='about'),
-    url(r'^post/(?P<slug>[-a-zA-Z0-9_]+)/$', views.post, name='post'),
+    path('post/<slug:slug>/', views.post, name='post'),
-    url(r'^weblog', include('blog.urls')),
+    re_path(r'^weblog', include('blog.urls')),
 ]

Existing re_path() calls are also rewritten to the path() syntax when eligible.

-from django.urls import include, re_path
+from django.urls import include, path, re_path

 urlpatterns = [
-    re_path(r'^about/$', views.about, name='about'),
+    path('about/', views.about, name='about'),
     re_path(r'^post/(?P<slug>[\w-]+)/$', views.post, name='post'),
 ]

The compatible regexes that will be converted to use path converters are the following:

• [^/]+ → str

• [0-9]+ → int

• [-a-zA-Z0-9_]+ → slug

• [0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12} → uuid

• .+ → path

These are taken from the path converter classes.

For some cases, this change alters the type of the arguments passed to the view, from str to the converted type (e.g. int). This is not guaranteed backwards compatible: there is a chance that the view expects a string, rather than the converted type. But, pragmatically, it seems 99.9% of views do not require strings, and instead work with either strings or the converted type. Thus, you should test affected paths after this fixer makes any changes.

Note that [\w-] is sometimes used for slugs, but is not converted because it might be incompatible. That pattern matches all Unicode word characters, such as “α”, unlike Django’s slug converter, which only matches Latin characters.

lru_cache

Rewrites imports of lru_cache from django.utils.functional to use functools.

-from django.utils.functional import lru_cache
+from functools import lru_cache

<func>.allow_tags = True

Removes assignments of allow_tags attributes to True. This was an admin feature to allow display functions to return HTML without marking it as unsafe, deprecated in Django 1.9. In practice, most display functions that return HTML already use format_html() or similar, so the attribute wasn’t necessary. This only applies in files that use from django.contrib import admin or from django.contrib.gis import admin.

 from django.contrib import admin

 def upper_case_name(obj):
     ...

-upper_case_name.allow_tags = True

HttpRequest.headers

Rewrites use of request.META to read HTTP headers to instead use request.headers. Header lookups are done in lowercase per the HTTP/2 specification.

-request.META['HTTP_ACCEPT_ENCODING']
+request.headers['accept-encoding']

-self.request.META.get('HTTP_SERVER', '')
+self.request.headers.get('server', '')

-request.META.get('CONTENT_LENGTH')
+request.headers.get('content-length')

-"HTTP_SERVER" in request.META
+"server" in request.headers

QuerySetPaginator

Rewrites deprecated alias django.core.paginator.QuerySetPaginator to Paginator.

-from django.core.paginator import QuerySetPaginator
+from django.core.paginator import Paginator

-QuerySetPaginator(...)
+Paginator(...)

FixedOffset

Rewrites deprecated class FixedOffset(x, y)) to timezone(timedelta(minutes=x), y)

Known limitation: this fixer will leave code broken with an ImportError if FixedOffset is called with only *args or **kwargs.

-from django.utils.timezone import FixedOffset
-FixedOffset(120, "Super time")
+from datetime import timedelta, timezone
+timezone(timedelta(minutes=120), "Super time")

FloatRangeField

Rewrites model and form fields using FloatRangeField to DecimalRangeField, from the relevant django.contrib.postgres modules.

 from django.db.models import Model
-from django.contrib.postgres.fields import FloatRangeField
+from django.contrib.postgres.fields import DecimalRangeField

 class MyModel(Model):
-    my_field = FloatRangeField("My range of numbers")
+    my_field = DecimalRangeField("My range of numbers")

TestCase class database declarations

Rewrites the allow_database_queries and multi_db attributes of Django’s TestCase classes to the new databases attribute. This only applies in test files, which are heuristically detected as files with either “test” or “tests” somewhere in their path.

Note that this will only rewrite to databases = [] or databases = "__all__". With multiple databases you can save some test time by limiting test cases to the databases they require (which is why Django made the change).

 from django.test import SimpleTestCase

 class MyTests(SimpleTestCase):
-    allow_database_queries = True
+    databases = "__all__"

     def test_something(self):
         self.assertEqual(2 * 2, 4)

django.utils.encoding aliases

Rewrites smart_text() to smart_str(), and force_text() to force_str().

-from django.utils.encoding import force_text, smart_text
+from django.utils.encoding import force_str, smart_str


-force_text("yada")
-smart_text("yada")
+force_str("yada")
+smart_str("yada")

django.utils.http deprecations

Rewrites the urlquote(), urlquote_plus(), urlunquote(), and urlunquote_plus() functions to the urllib.parse versions. Also rewrites the internal function is_safe_url() to url_has_allowed_host_and_scheme().

-from django.utils.http import urlquote
+from urllib.parse import quote

-escaped_query_string = urlquote(query_string)
+escaped_query_string = quote(query_string)

django.utils.text deprecation

Rewrites unescape_entities() with the standard library html.escape().

-from django.utils.text import unescape_entities
+import html

-unescape_entities("some input string")
+html.escape("some input string")

django.utils.translation deprecations

Rewrites the ugettext(), ugettext_lazy(), ugettext_noop(), ungettext(), and ungettext_lazy() functions to their non-u-prefixed versions.

-from django.utils.translation import ugettext as _, ungettext
+from django.utils.translation import gettext as _, ngettext

-ungettext("octopus", "octopodes", n)
+ngettext("octopus", "octopodes", n)

JSONField

Rewrites imports of JSONField and related transform classes from those in django.contrib.postgres to the new all-database versions. Ignores usage in migration files, since Django kept the old class around to support old migrations. You will need to make migrations after this fix makes changes to models.

-from django.contrib.postgres.fields import JSONField
+from django.db.models import JSONField

PASSWORD_RESET_TIMEOUT_DAYS

Rewrites the setting PASSWORD_RESET_TIMEOUT_DAYS to PASSWORD_RESET_TIMEOUT, adding the multiplication by the number of seconds in a day.

Settings files are heuristically detected as modules with the whole word “settings” somewhere in their path. For example myproject/settings.py or myproject/settings/production.py.

-PASSWORD_RESET_TIMEOUT_DAYS = 4
+PASSWORD_RESET_TIMEOUT = 60 * 60 * 24 * 4

Signal

Removes the deprecated documentation-only providing_args argument.

 from django.dispatch import Signal
-my_cool_signal = Signal(providing_args=["documented", "arg"])
+my_cool_signal = Signal()

get_random_string

Injects the now-required length argument, with its previous default 12.

 from django.utils.crypto import get_random_string
-key = get_random_string(allowed_chars="01234567899abcdef")
+key = get_random_string(length=12, allowed_chars="01234567899abcdef")

NullBooleanField

Transforms the NullBooleanField() model field to BooleanField(null=True). Ignores usage in migration files, since Django kept the old class around to support old migrations. You will need to make migrations after this fix makes changes to models.

-from django.db.models import Model, NullBooleanField
+from django.db.models import Model, BooleanField

 class Book(Model):
-    valuable = NullBooleanField("Valuable")
+    valuable = BooleanField("Valuable", null=True)

ModelMultipleChoiceField

Replace list error message key with list_invalid on forms ModelMultipleChoiceField.

-forms.ModelMultipleChoiceField(error_messages={"list": "Enter multiple values."})
+forms.ModelMultipleChoiceField(error_messages={"invalid_list": "Enter multiple values."})

@admin.action()

Rewrites functions that have admin action attributes assigned to them to use the new @admin.action() decorator. This only applies in files that use from django.contrib import admin or from django.contrib.gis import admin.

 from django.contrib import admin

 # Module-level actions:

+@admin.action(
+    description="Publish articles",
+)
 def make_published(modeladmin, request, queryset):
     ...

-make_published.short_description = "Publish articles"

 # …and within classes:

 @admin.register(Book)
 class BookAdmin(admin.ModelAdmin):
+    @admin.action(
+        description="Unpublish articles",
+        permissions=("unpublish",),
+    )
     def make_unpublished(self, request, queryset):
         ...

-    make_unpublished.allowed_permissions = ("unpublish",)
-    make_unpublished.short_description = "Unpublish articles"

@admin.display()

Rewrites functions that have admin display attributes assigned to them to use the new @admin.display() decorator. This only applies in files that use from django.contrib import admin or from django.contrib.gis import admin.

 from django.contrib import admin

 # Module-level display functions:

+@admin.display(
+    description="NAME",
+)
 def upper_case_name(obj):
     ...

-upper_case_name.short_description = "NAME"

 # …and within classes:

 @admin.register(Book)
 class BookAdmin(admin.ModelAdmin):
+    @admin.display(
+        description='Is Published?',
+        boolean=True,
+        ordering='-publish_date',
+    )
     def is_published(self, obj):
         ...

-    is_published.boolean = True
-    is_published.admin_order_field = '-publish_date'
-    is_published.short_description = 'Is Published?'

BaseCommand.requires_system_checks

Rewrites the requires_system_checks attributes of management command classes from bools to "__all__" or [] as appropriate. This only applies in command files, which are heuristically detected as files with management/commands somewhere in their path.

 from django.core.management.base import BaseCommand

 class Command(BaseCommand):
-    requires_system_checks = True
+    requires_system_checks = "__all__"

 class SecondCommand(BaseCommand):
-    requires_system_checks = False
+    requires_system_checks = []

EmailValidator

Rewrites the whitelist keyword argument to its new name allowlist.

 from django.core.validators import EmailValidator

-EmailValidator(whitelist=["example.com"])
+EmailValidator(allowlist=["example.com"])

default_app_config

Removes module-level default_app_config assignments from __init__.py files:

-default_app_config = 'my_app.apps.AppConfig'

USE_L10N

Removes the deprecated USE_L10N setting if set to its default value of True.

Settings files are heuristically detected as modules with the whole word “settings” somewhere in their path. For example myproject/settings.py or myproject/settings/production.py.

-USE_L10N = True

django.utils.timezone.utc deprecations

Rewrites imports of django.utils.timezone.utc to use datetime.timezone.utc. Requires an existing import of the datetime module.

 import datetime
-from django.utils.timezone import utc

-calculate_some_datetime(utc)
+calculate_some_datetime(datetime.timezone.utc)

 import datetime as dt
 from django.utils import timezone


-do_a_thing(timezone.utc)
+do_a_thing(dt.timezone.utc)

assertFormError() and assertFormsetError()

Rewrites calls to these assertion functions from the old signature to the new one.

-self.assertFormError(response, "form", "username", ["Too long"])
+self.assertFormError(response.context["form"], "username", ["Too long"])

-self.assertFormError(response, "form", "username", None)
+self.assertFormError(response.context["form"], "username", [])

-self.assertFormsetError(response, "formset", 0, "username", ["Too long"])
+self.assertFormsetError(response.context["formset"], 0, "username", ["Too long"])

-self.assertFormsetError(response, "formset", 0, "username", None)
+self.assertFormsetError(response.context["formset"], 0, "username", [])