Django 1.11 release notes¶

Class-based model indexes¶

The new django.db.models.indexes module contains classes which ease creating database indexes. Indexes are added to models using the Meta.indexes option.

The Index class creates a b-tree index, as if you used db_index on the model field or index_together on the model Meta class. It can be subclassed to support different index types, such as GinIndex. It also allows defining the order (ASC/DESC) for the columns of the index.

Template-based widget rendering¶

To ease customizing widgets, form widget rendering is now done using the template system rather than in Python. See The form rendering API.

You may need to adjust any custom widgets that you’ve written for a few backwards incompatible changes.

Subquery expressions¶

The new Subquery and Exists database expressions allow creating explicit subqueries. Subqueries may refer to fields from the outer queryset using the OuterRef class.

Minor features¶

django.contrib.gis¶

• To simplify the codebase and because it’s easier to install than when contrib.gis was first released, GDAL is now a required dependency for GeoDjango. In older versions, it’s only required for SQLite.
• contrib.gis.maps is removed as it interfaces with a retired version of the Google Maps API and seems to be unmaintained. If you’re using it, let us know.
• The GEOSGeometry equality operator now also compares SRID.
• The OpenLayers-based form widgets now use OpenLayers 3, and the gis/openlayers.html and gis/openlayers-osm.html templates have been updated. Check your project if you subclass these widgets or extend the templates. Also, the new widgets work a bit differently than the old ones. Instead of using a toolbar in the widget, you click to draw, click and drag to move the map, and click and drag a point/vertex/corner to move it.
• Support for SpatiaLite < 4.0 is dropped.
• Support for GDAL 1.7 and 1.8 is dropped.
• The widgets in contrib.gis.forms.widgets and the admin’s OpenLayersWidget use the form rendering API rather than loader.render_to_string(). If you’re using a custom widget template, you’ll need to be sure your form renderer can locate it. For example, you could use the TemplatesSetting renderer.

django.contrib.staticfiles¶

• collectstatic may now fail during post-processing when using a hashed static files storage if a reference loop exists (e.g. 'foo.css' references 'bar.css' which itself references 'foo.css') or if the chain of files referencing other files is too deep to resolve in several passes. In the latter case, increase the number of passes using ManifestStaticFilesStorage.max_post_process_passes.
• When using ManifestStaticFilesStorage, static files not found in the manifest at runtime now raise a ValueError instead of returning an unchanged path. You can revert to the old behavior by setting ManifestStaticFilesStorage.manifest_strict to False.

Database backend API¶

This section describes changes that may be needed in third-party database backends.

• The DatabaseOperations.time_trunc_sql() method is added to support TimeField truncation. It accepts a lookup_type and field_name arguments and returns the appropriate SQL to truncate the given time field field_name to a time object with only the given specificity. The lookup_type argument can be either 'hour', 'minute', or 'second'.
• The DatabaseOperations.datetime_cast_time_sql() method is added to support the time lookup. It accepts a field_name and tzname arguments and returns the SQL necessary to cast a datetime value to time value.
• To enable FOR UPDATE SKIP LOCKED support, set DatabaseFeatures.has_select_for_update_skip_locked = True.
• The new DatabaseFeatures.supports_index_column_ordering attribute specifies if a database allows defining ordering for columns in indexes. The default value is True and the DatabaseIntrospection.get_constraints() method should include an 'orders' key in each of the returned dictionaries with a list of 'ASC' and/or 'DESC' values corresponding to the ordering of each column in the index.
• inspectdb no longer calls DatabaseIntrospection.get_indexes() which is deprecated. Custom database backends should ensure all types of indexes are returned by DatabaseIntrospection.get_constraints().
• Renamed the ignores_quoted_identifier_case feature to ignores_table_name_case to more accurately reflect how it is used.
• The name keyword argument is added to the DatabaseWrapper.create_cursor(self, name=None) method to allow usage of server-side cursors on backends that support it.

Dropped support for PostgreSQL 9.2 and PostGIS 2.0¶

Upstream support for PostgreSQL 9.2 ends in September 2017. As a consequence, Django 1.11 sets PostgreSQL 9.3 as the minimum version it officially supports.

Support for PostGIS 2.0 is also removed as PostgreSQL 9.2 is the last version to support it.

Also, the minimum supported version of psycopg2 is increased from 2.4.5 to 2.5.4.

LiveServerTestCase binds to port zero¶

Rather than taking a port range and iterating to find a free port, LiveServerTestCase binds to port zero and relies on the operating system to assign a free port. The DJANGO_LIVE_TEST_SERVER_ADDRESS environment variable is no longer used, and as it’s also no longer used, the manage.py test --liveserver option is removed.

If you need to bind LiveServerTestCase to a specific port, use the port attribute added in Django 1.11.2.

Protection against insecure redirects in django.contrib.auth and i18n views¶

LoginView, LogoutView (and the deprecated function-based equivalents), and set_language() protect users from being redirected to non-HTTPS next URLs when the app is running over HTTPS.

QuerySet.get_or_create() and update_or_create() validate arguments¶

To prevent typos from passing silently, get_or_create() and update_or_create() check that their arguments are model fields. This should be backwards-incompatible only in the fact that it might expose a bug in your project.

pytz is a required dependency and support for settings.TIME_ZONE = None is removed¶

To simplify Django’s timezone handling, pytz is now a required dependency. It’s automatically installed along with Django.

Support for settings.TIME_ZONE = None is removed as the behavior isn’t commonly used and is questionably useful. If you want to automatically detect the timezone based on the system timezone, you can use tzlocal:

from tzlocal import get_localzone

TIME_ZONE = get_localzone().zone

This works similar to settings.TIME_ZONE = None except that it also sets os.environ['TZ']. Let us know if there’s a use case where you find you can’t adapt your code to set a TIME_ZONE.

HTML changes in admin templates¶

<p class="help"> is replaced with a <div> tag to allow including lists inside help text.

Read-only fields are wrapped in <div class="readonly">...</div> instead of <p>...</p> to allow any kind of HTML as the field’s content.

Changes due to the introduction of template-based widget rendering¶

Some undocumented classes in django.forms.widgets are removed:

• SubWidget
• RendererMixin, ChoiceFieldRenderer, RadioFieldRenderer, CheckboxFieldRenderer
• ChoiceInput, RadioChoiceInput, CheckboxChoiceInput

The undocumented Select.render_option() method is removed.

The Widget.format_output() method is removed. Use a custom widget template instead.

Some widget values, such as <select> options, are now localized if settings.USE_L10N=True. You could revert to the old behavior with custom widget templates that uses the localize template tag to turn off localization.

django.template.backends.django.Template.render() prohibits non-dict context¶

For compatibility with multiple template engines, django.template.backends.django.Template.render() (returned from high-level template loader APIs such as loader.get_template()) must receive a dictionary of context rather than Context or RequestContext. If you were passing either of the two classes, pass a dictionary instead – doing so is backwards-compatible with older versions of Django.

Model state changes in migration operations¶

To improve the speed of applying migrations, rendering of related models is delayed until an operation that needs them (e.g. RunPython). If you have a custom operation that works with model classes or model instances from the from_state argument in database_forwards() or database_backwards(), you must render model states using the clear_delayed_apps_cache() method as described in writing your own migration operation.

Server-side cursors on PostgreSQL¶

The change to make QuerySet.iterator() use server-side cursors on PostgreSQL prevents running Django with pgBouncer in transaction pooling mode. To reallow that, use the DISABLE_SERVER_SIDE_CURSORS setting (added in Django 1.11.1) in DATABASES.

See Transaction pooling and server-side cursors for more discussion.

Miscellaneous¶

• If no items in the feed have a pubdate or updateddate attribute, SyndicationFeed.latest_post_date() now returns the current UTC date/time, instead of a datetime without any timezone information.

• CSRF failures are logged to the django.security.csrf logger instead of django.request.

• ALLOWED_HOSTS validation is no longer disabled when running tests. If your application includes tests with custom host names, you must include those host names in ALLOWED_HOSTS. See Tests and multiple host names.

• Using a foreign key’s id (e.g. 'field_id') in ModelAdmin.list_display displays the related object’s ID. Remove the _id suffix if you want the old behavior of the string representation of the object.

• In model forms, CharField with null=True now saves NULL for blank values instead of empty strings.

• On Oracle, Model.validate_unique() no longer checks empty strings for uniqueness as the database interprets the value as NULL.

• If you subclass AbstractUser and override clean(), be sure it calls super(). BaseUserManager.normalize_email() is called in a new AbstractUser.clean() method so that normalization is applied in cases like model form validation.

• EmailField and URLField no longer accept the strip keyword argument. Remove it because it doesn’t have an effect in older versions of Django as these fields always strip whitespace.

• The checked and selected attribute rendered by form widgets now uses HTML5 boolean syntax rather than XHTML’s checked='checked' and selected='selected'.

• RelatedManager.add(), remove(), clear(), and set() now clear the prefetch_related() cache.

• To prevent possible loss of saved settings, setup_test_environment() now raises an exception if called a second time before calling teardown_test_environment().

• The undocumented DateTimeAwareJSONEncoder alias for DjangoJSONEncoder (renamed in Django 1.0) is removed.

• The cached template loader is now enabled if OPTIONS['loaders'] isn’t specified and OPTIONS['debug'] is False (the latter option defaults to the value of DEBUG). This could be backwards-incompatible if you have some template tags that aren’t thread safe.

• The prompt for stale content type deletion no longer occurs after running the migrate command. Use the new remove_stale_contenttypes command instead.

• The admin’s widget for IntegerField uses type="number" rather than type="text".

• Conditional HTTP headers are now parsed and compared according to the RFC 7232 Conditional Requests specification rather than the older RFC 2616.

• patch_response_headers() no longer adds a Last-Modified header. According to the RFC 7234#section-4.2.2, this header is useless alongside other caching headers that provide an explicit expiration time, e.g. Expires or Cache-Control. UpdateCacheMiddleware and add_never_cache_headers() call patch_response_headers() and therefore are also affected by this change.

• In the admin templates, <p class="help"> is replaced with a <div> tag to allow including lists inside help text.

• ConditionalGetMiddleware no longer sets the Date header as Web servers set that header. It also no longer sets the Content-Length header as this is now done by CommonMiddleware.

  If you have a middleware that modifies a response’s content and appears before CommonMiddleware in the MIDDLEWARE or MIDDLEWARE_CLASSES settings, you must reorder your middleware so that responses aren’t modified after Content-Length is set, or have the response modifying middleware reset the Content-Length header.

• get_model() and get_models() now raise AppRegistryNotReady if they’re called before models of all applications have been loaded. Previously they only required the target application’s models to be loaded and thus could return models without all their relations set up. If you need the old behavior of get_model(), set the require_ready argument to False.

• The unused BaseCommand.can_import_settings attribute is removed.

• The undocumented django.utils.functional.lazy_property is removed.

• For consistency with non-multipart requests, MultiPartParser.parse() now leaves request.POST immutable. If you’re modifying that QueryDict, you must now first copy it, e.g. request.POST.copy().

• Support for cx_Oracle < 5.2 is removed.

• Support for IPython < 1.0 is removed from the shell command.

• The signature of private API Widget.build_attrs() changed from extra_attrs=None, **kwargs to base_attrs, extra_attrs=None.

• File-like objects (e.g., StringIO and BytesIO) uploaded to an ImageField using the test client now require a name attribute with a value that passes the validate_image_file_extension validator. See the note in Client.post().

• FileField now moves rather than copies the file it receives. With the default file upload settings, files larger than FILE_UPLOAD_MAX_MEMORY_SIZE now have the same permissions as temporary files (often 0o600) rather than the system’s standard umask (often 0o6644). Set the FILE_UPLOAD_PERMISSIONS if you need the same permission regardless of file size.

models.permalink() decorator¶

Use django.urls.reverse() instead. For example:

from django.db import models

class MyModel(models.Model):
    ...

    @models.permalink
    def url(self):
        return ('guitarist_detail', [self.slug])

becomes:

from django.db import models
from django.urls import reverse

class MyModel(models.Model):
    ...

    def url(self):
        return reverse('guitarist_detail', args=[self.slug])

Miscellaneous¶

• contrib.auth’s login() and logout() function-based views are deprecated in favor of new class-based views LoginView and LogoutView.
• The unused extra_context parameter of contrib.auth.views.logout_then_login() is deprecated.
• contrib.auth’s password_change(), password_change_done(), password_reset(), password_reset_done(), password_reset_confirm(), and password_reset_complete() function-based views are deprecated in favor of new class-based views PasswordChangeView, PasswordChangeDoneView, PasswordResetView, PasswordResetDoneView, PasswordResetConfirmView, and PasswordResetCompleteView.
• django.test.runner.setup_databases() is moved to django.test.utils.setup_databases(). The old location is deprecated.
• django.utils.translation.string_concat() is deprecated in favor of django.utils.text.format_lazy(). string_concat(*strings) can be replaced by format_lazy('{}' * len(strings), *strings).
• For the PyLibMCCache cache backend, passing pylibmc behavior settings as top-level attributes of OPTIONS is deprecated. Set them under a behaviors key within OPTIONS instead.
• The host parameter of django.utils.http.is_safe_url() is deprecated in favor of the new allowed_hosts parameter.
• Silencing exceptions raised while rendering the {% include %} template tag is deprecated as the behavior is often more confusing than helpful. In Django 2.1, the exception will be raised.
• DatabaseIntrospection.get_indexes() is deprecated in favor of DatabaseIntrospection.get_constraints().
• authenticate() now passes a request argument to the authenticate() method of authentication backends. Support for methods that don’t accept request as the first positional argument will be removed in Django 2.1.
• The USE_ETAGS setting is deprecated in favor of ConditionalGetMiddleware which now adds the ETag header to responses regardless of the setting. CommonMiddleware and django.utils.cache.patch_response_headers() will no longer set ETags when the deprecation ends.
• Model._meta.has_auto_field is deprecated in favor of checking if Model._meta.auto_field is not None.
• Using regular expression groups with iLmsu# in url() is deprecated. The only group that’s useful is (?i) for case-insensitive URLs, however, case-insensitive URLs aren’t a good practice because they create multiple entries for search engines, for example. An alternative solution could be to create a handler404 that looks for uppercase characters in the URL and redirects to a lowercase equivalent.
• The renderer argument is added to the Widget.render() method. Methods that don’t accept that argument will work through a deprecation period.