Django 3.2 release notes

April 6, 2021

Welcome to Django 3.2!

These release notes cover the new features, as well as some backwards incompatible changes you’ll want to be aware of when upgrading from Django 3.1 or earlier. We’ve begun the deprecation process for some features.

See the How to upgrade Django to a newer version guide if you’re updating an existing project.

Django 3.2 is designated as a long-term support release. It will receive security updates for at least three years after its release. Support for the previous LTS, Django 2.2, will end in April 2022.

Python compatibility

Django 3.2 supports Python 3.6, 3.7, 3.8, 3.9, and 3.10 (as of 3.2.9). We highly recommend and only officially support the latest release of each series.

What’s new in Django 3.2

Automatic AppConfig discovery

Most pluggable applications define an AppConfig subclass in an apps.py submodule. Many define a default_app_config variable pointing to this class in their __init__.py.

When the apps.py submodule exists and defines a single AppConfig subclass, Django now uses that configuration automatically, so you can remove default_app_config.

default_app_config made it possible to declare only the application’s path in INSTALLED_APPS (e.g. 'django.contrib.admin') rather than the app config’s path (e.g. 'django.contrib.admin.apps.AdminConfig'). It was introduced for backwards-compatibility with the former style, with the intent to switch the ecosystem to the latter, but the switch didn’t happen.

With automatic AppConfig discovery, default_app_config is no longer needed. As a consequence, it’s deprecated.

See Configuring applications for full details.

Customizing type of auto-created primary keys

When defining a model, if no field in a model is defined with primary_key=True an implicit primary key is added. The type of this implicit primary key can now be controlled via the DEFAULT_AUTO_FIELD setting and AppConfig.default_auto_field attribute. No more needing to override primary keys in all models.

Maintaining the historical behavior, the default value for DEFAULT_AUTO_FIELD is AutoField. Starting with 3.2 new projects are generated with DEFAULT_AUTO_FIELD set to BigAutoField. Also, new apps are generated with AppConfig.default_auto_field set to BigAutoField. In a future Django release the default value of DEFAULT_AUTO_FIELD will be changed to BigAutoField.

To avoid unwanted migrations in the future, either explicitly set DEFAULT_AUTO_FIELD to AutoField:

DEFAULT_AUTO_FIELD = "django.db.models.AutoField"

or configure it on a per-app basis:

from django.apps import AppConfig


class MyAppConfig(AppConfig):
    default_auto_field = "django.db.models.AutoField"
    name = "my_app"

or on a per-model basis:

from django.db import models


class MyModel(models.Model):
    id = models.AutoField(primary_key=True)

In anticipation of the changing default, a system check will provide a warning if you do not have an explicit setting for DEFAULT_AUTO_FIELD.

When changing the value of DEFAULT_AUTO_FIELD, migrations for the primary key of existing auto-created through tables cannot be generated currently. See the DEFAULT_AUTO_FIELD docs for details on migrating such tables.

Functional indexes

The new *expressions positional argument of Index() enables creating functional indexes on expressions and database functions. For example:

from django.db import models
from django.db.models import F, Index, Value
from django.db.models.functions import Lower, Upper


class MyModel(models.Model):
    first_name = models.CharField(max_length=255)
    last_name = models.CharField(max_length=255)
    height = models.IntegerField()
    weight = models.IntegerField()

    class Meta:
        indexes = [
            Index(
                Lower("first_name"),
                Upper("last_name").desc(),
                name="first_last_name_idx",
            ),
            Index(
                F("height") / (F("weight") + Value(5)),
                name="calc_idx",
            ),
        ]

Functional indexes are added to models using the Meta.indexes option.

pymemcache support

The new django.core.cache.backends.memcached.PyMemcacheCache cache backend allows using the pymemcache library for memcached. pymemcache 3.4.0 or higher is required. For more details, see the documentation on caching in Django.

New decorators for the admin site

The new display() decorator allows for easily adding options to custom display functions that can be used with list_display or readonly_fields.

Likewise, the new action() decorator allows for easily adding options to action functions that can be used with actions.

Using the @display decorator has the advantage that it is now possible to use the @property decorator when needing to specify attributes on the custom method. Prior to this it was necessary to use the property() function instead after assigning the required attributes to the method.

Using decorators has the advantage that these options are more discoverable as they can be suggested by completion utilities in code editors. They are merely a convenience and still set the same attributes on the functions under the hood.

Minor features

django.contrib.admin

  • ModelAdmin.search_fields now allows searching against quoted phrases with spaces.

  • Read-only related fields are now rendered as navigable links if target models are registered in the admin.

  • The admin now supports theming, and includes a dark theme that is enabled according to browser settings. See Theming support for more details.

  • ModelAdmin.autocomplete_fields now respects ForeignKey.to_field and ForeignKey.limit_choices_to when searching a related model.

  • The admin now installs a final catch-all view that redirects unauthenticated users to the login page, regardless of whether the URL is otherwise valid. This protects against a potential model enumeration privacy issue.

    Although not recommended, you may set the new AdminSite.final_catch_all_view to False to disable the catch-all view.

django.contrib.auth

  • The default iteration count for the PBKDF2 password hasher is increased from 216,000 to 260,000.

  • The default variant for the Argon2 password hasher is changed to Argon2id. memory_cost and parallelism are increased to 102,400 and 8 respectively to match the argon2-cffi defaults.

    Increasing the memory_cost pushes the required memory from 512 KB to 100 MB. This is still rather conservative but can lead to problems in memory constrained environments. If this is the case, the existing hasher can be subclassed to override the defaults.

  • The default salt entropy for the Argon2, MD5, PBKDF2, SHA-1 password hashers is increased from 71 to 128 bits.

django.contrib.contenttypes

django.contrib.gis

django.contrib.postgres

  • The new ExclusionConstraint.include attribute allows creating covering exclusion constraints on PostgreSQL 12+.
  • The new ExclusionConstraint.opclasses attribute allows setting PostgreSQL operator classes.
  • The new JSONBAgg.ordering attribute determines the ordering of the aggregated elements.
  • The new JSONBAgg.distinct attribute determines if aggregated values will be distinct.
  • The CreateExtension operation now checks that the extension already exists in the database and skips the migration if so.
  • The new CreateCollation and RemoveCollation operations allow creating and dropping collations on PostgreSQL. See Managing collations using migrations for more details.
  • Lookups for ArrayField now allow (non-nested) arrays containing expressions as right-hand sides.
  • The new OpClass() expression allows creating functional indexes on expressions with a custom operator class. See Functional indexes for more details.

django.contrib.sitemaps

django.contrib.syndication

  • The new item_comments hook allows specifying a comments URL per feed item.

Database backends

  • Third-party database backends can now skip or mark as expected failures tests in Django’s test suite using the new DatabaseFeatures.django_test_skips and django_test_expected_failures attributes.

Decorators

Error Reporting

File Uploads

Forms

Generic Views

Management Commands

  • loaddata now supports fixtures stored in XZ archives (.xz) and LZMA archives (.lzma).
  • dumpdata now can compress data in the bz2, gz, lzma, or xz formats.
  • makemigrations can now be called without an active database connection. In that case, check for a consistent migration history is skipped.
  • BaseCommand.requires_system_checks now supports specifying a list of tags. System checks registered in the chosen tags will be checked for errors prior to executing the command. In previous versions, either all or none of the system checks were performed.
  • Support for colored terminal output on Windows is updated. Various modern terminal environments are automatically detected, and the options for enabling support in other cases are improved. See Syntax coloring for more details.

Migrations

  • The new Operation.migration_name_fragment property allows providing a filename fragment that will be used to name a migration containing only that operation.
  • Migrations now support serialization of pure and concrete path objects from pathlib, and os.PathLike instances.

Models

Pagination

Requests and Responses

Security

Serialization

  • The new JSONL serializer allows using the JSON Lines format with dumpdata and loaddata. This can be useful for populating large databases because data is loaded line by line into memory, rather than being loaded all at once.

Signals

Templates

Tests

Utilities

  • The new depth parameter of django.utils.timesince.timesince() and django.utils.timesince.timeuntil() functions allows specifying the number of adjacent time units to return.

Validators

  • Built-in validators now include the provided value in the params argument of a raised ValidationError. This allows custom error messages to use the %(value)s placeholder.
  • The ValidationError equality operator now ignores messages and params ordering.

Backwards incompatible changes in 3.2

Database backend API

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

  • The new DatabaseFeatures.introspected_field_types property replaces these features:
    • can_introspect_autofield
    • can_introspect_big_integer_field
    • can_introspect_binary_field
    • can_introspect_decimal_field
    • can_introspect_duration_field
    • can_introspect_ip_address_field
    • can_introspect_positive_integer_field
    • can_introspect_small_integer_field
    • can_introspect_time_field
    • introspected_big_auto_field_type
    • introspected_small_auto_field_type
    • introspected_boolean_field_type
  • To enable support for covering indexes (Index.include) and covering unique constraints (UniqueConstraint.include), set DatabaseFeatures.supports_covering_indexes to True.
  • Third-party database backends must implement support for column database collations on CharFields and TextFields or set DatabaseFeatures.supports_collation_on_charfield and DatabaseFeatures.supports_collation_on_textfield to False. If non-deterministic collations are not supported, set supports_non_deterministic_collations to False.
  • DatabaseOperations.random_function_sql() is removed in favor of the new Random database function.
  • DatabaseOperations.date_trunc_sql() and DatabaseOperations.time_trunc_sql() now take the optional tzname argument in order to truncate in a specific timezone.
  • DatabaseClient.runshell() now gets arguments and an optional dictionary with environment variables to the underlying command-line client from DatabaseClient.settings_to_cmd_args_env() method. Third-party database backends must implement DatabaseClient.settings_to_cmd_args_env() or override DatabaseClient.runshell().
  • Third-party database backends must implement support for functional indexes (Index.expressions) or set DatabaseFeatures.supports_expression_indexes to False. If COLLATE is not a part of the CREATE INDEX statement, set DatabaseFeatures.collate_as_index_expression to True.

django.contrib.admin

  • Pagination links in the admin are now 1-indexed instead of 0-indexed, i.e. the query string for the first page is ?p=1 instead of ?p=0.
  • The new admin catch-all view will break URL patterns routed after the admin URLs and matching the admin URL prefix. You can either adjust your URL ordering or, if necessary, set AdminSite.final_catch_all_view to False, disabling the catch-all view. See What’s new in Django 3.2 for more details.
  • Minified JavaScript files are no longer included with the admin. If you require these files to be minified, consider using a third party app or external build tool. The minified vendored JavaScript files packaged with the admin (e.g. jquery.min.js) are still included.
  • ModelAdmin.prepopulated_fields no longer strips English stop words, such as 'a' or 'an'.

django.contrib.gis

  • Support for PostGIS 2.2 is removed.
  • The Oracle backend now clones polygons (and geometry collections containing polygons) before reorienting them and saving them to the database. They are no longer mutated in place. You might notice this if you use the polygons after a model is saved.

Dropped support for PostgreSQL 9.5

Upstream support for PostgreSQL 9.5 ends in February 2021. Django 3.2 supports PostgreSQL 9.6 and higher.

Dropped support for MySQL 5.6

The end of upstream support for MySQL 5.6 is April 2021. Django 3.2 supports MySQL 5.7 and higher.

Miscellaneous

  • Django now supports non-pytz time zones, such as Python 3.9+’s zoneinfo module and its backport.

  • The undocumented SpatiaLiteOperations.proj4_version() method is renamed to proj_version().

  • slugify() now removes leading and trailing dashes and underscores.

  • The intcomma and intword template filters no longer depend on the USE_L10N setting.

  • Support for argon2-cffi < 19.1.0 is removed.

  • The cache keys no longer includes the language when internationalization is disabled (USE_I18N = False) and localization is enabled (USE_L10N = True). After upgrading to Django 3.2 in such configurations, the first request to any previously cached value will be a cache miss.

  • ForeignKey.validate() now uses _base_manager rather than _default_manager to check that related instances exist.

  • When an application defines an AppConfig subclass in an apps.py submodule, Django now uses this configuration automatically, even if it isn’t enabled with default_app_config. Set default = False in the AppConfig subclass if you need to prevent this behavior. See What’s new in Django 3.2 for more details.

  • Instantiating an abstract model now raises TypeError.

  • Keyword arguments to setup_databases() are now keyword-only.

  • The undocumented django.utils.http.limited_parse_qsl() function is removed. Please use urllib.parse.parse_qsl() instead.

  • django.test.utils.TestContextDecorator now uses addCleanup() so that cleanups registered in the setUp() method are called before TestContextDecorator.disable().

  • SessionMiddleware now raises a SessionInterrupted exception instead of SuspiciousOperation when a session is destroyed in a concurrent request.

  • The django.db.models.Field equality operator now correctly distinguishes inherited field instances across models. Additionally, the ordering of such fields is now defined.

  • The undocumented django.core.files.locks.lock() function now returns False if the file cannot be locked, instead of raising BlockingIOError.

  • The password reset mechanism now invalidates tokens when the user email is changed.

  • makemessages command no longer processes invalid locales specified using makemessages --locale option, when they contain hyphens ('-').

  • The django.contrib.auth.forms.ReadOnlyPasswordHashField form field is now disabled by default. Therefore UserChangeForm.clean_password() is no longer required to return the initial value.

  • The cache.get_many(), get_or_set(), has_key(), incr(), decr(), incr_version(), and decr_version() cache operations now correctly handle None stored in the cache, in the same way as any other value, instead of behaving as though the key didn’t exist.

    Due to a python-memcached limitation, the previous behavior is kept for the deprecated MemcachedCache backend.

  • The minimum supported version of SQLite is increased from 3.8.3 to 3.9.0.

  • CookieStorage now stores messages in the RFC 6265 compliant format. Support for cookies that use the old format remains until Django 4.1.

  • The minimum supported version of asgiref is increased from 3.2.10 to 3.3.2.

Features deprecated in 3.2

Miscellaneous

  • Assigning objects which don’t support creating deep copies with copy.deepcopy() to class attributes in TestCase.setUpTestData() is deprecated.
  • Using a boolean value in BaseCommand.requires_system_checks is deprecated. Use '__all__' instead of True, and [] (an empty list) instead of False.
  • The whitelist argument and domain_whitelist attribute of EmailValidator are deprecated. Use allowlist instead of whitelist, and domain_allowlist instead of domain_whitelist. You may need to rename whitelist in existing migrations.
  • The default_app_config application configuration variable is deprecated, due to the now automatic AppConfig discovery. See What’s new in Django 3.2 for more details.
  • Automatically calling repr() on a queryset in TransactionTestCase.assertQuerysetEqual(), when compared to string values, is deprecated. If you need the previous behavior, explicitly set transform to repr.
  • The django.core.cache.backends.memcached.MemcachedCache backend is deprecated as python-memcached has some problems and seems to be unmaintained. Use django.core.cache.backends.memcached.PyMemcacheCache or django.core.cache.backends.memcached.PyLibMCCache instead.
  • The format of messages used by django.contrib.messages.storage.cookie.CookieStorage is different from the format generated by older versions of Django. Support for the old format remains until Django 4.1.
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