Django 3.2 release notes

    Welcome to Django 3.2!

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

    如果你要更新现有的项目，请看 升级 Django 到最新的版本 指南。

    Django 3.2 is designated as a . 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.

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

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

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

    or configure it on a per-app basis:

    or on a per-model basis:

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

    Functional indexes

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

    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 library for memcached. pymemcache 3.4.0 or higher is required. For more details, see the documentation on caching in Django.

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

    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.

    次要特性

    django.contrib.admin

    • 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.

    • now respects ForeignKey.to_field and 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.

    • 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

    • The new absolute_max argument for allows customizing the maximum number of forms that can be instantiated when supplying POST data. See Limiting the maximum number of instantiated forms for more details.
    • The new can_delete_extra argument for allows removal of the option to delete extra forms. See can_delete_extra for more information.

    django.contrib.postgres

    • The new attribute allows setting PostgreSQL operator classes.
    • The new JSONBAgg.ordering attribute determines the ordering of the aggregated elements.
    • The new 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 and RemoveCollation operations allow creating and dropping collations on PostgreSQL. See for more details.
    • Lookups for ArrayField now allow (non-nested) arrays containing expressions as right-hand sides.
    • The new expression allows creating functional indexes on expressions with a custom operator class. See Functional indexes for more details.

    • The new Sitemap attributes , languages and allow generating sitemap alternates to localized versions of your pages.

    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

    • The new decorator allows individual views to be excluded from APPEND_SLASH URL normalization.

    错误报告

    • Custom subclasses can now define the html_template_path and properties to override the templates used to render exception reports.

    文件上传

    表单

    • The new absolute_max argument for , inlineformset_factory(), and allows customizing the maximum number of forms that can be instantiated when supplying POST data. See Limiting the maximum number of instantiated forms for more details.
    • The new can_delete_extra argument for , inlineformset_factory(), and allows removal of the option to delete extra forms. See can_delete_extra for more information.
    • now reports a user facing error, rather than raising an exception, when the management form is missing or has been tampered with. To customize this error message, pass the error_messages argument with the key 'missing_management_form' when instantiating the formset.

    Generic Views

    • The week_format attributes of WeekMixin and now support the ISO 8601 week format.

    管理命令

    • loaddata now supports fixtures stored in XZ archives (.xz) and LZMA archives (.lzma).
    • 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.
    • 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 语法着色 for more details.

    迁移

    • 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 , and os.PathLike instances.

    模型

    • The new no_key parameter for , supported on PostgreSQL, allows acquiring weaker locks that don’t block the creation of rows that reference locked rows through a foreign key.
    • When() expression now allows using the condition argument with lookups.
    • The new and UniqueConstraint.include attributes allow creating covering indexes and covering unique constraints on PostgreSQL 11+.
    • The new attribute allows setting PostgreSQL operator classes.
    • The QuerySet.update() method now respects the order_by() clause on MySQL and MariaDB.
    • now supports nested relations.
    • The of argument of QuerySet.select_for_update() is now allowed on MySQL 8.0.1+.
    • expression now automatically resolves its output_field to the appropriate Field subclass based on the type of its provided value for , bytes, , int, , datetime.date, , datetime.time, , decimal.Decimal, and instances. As a consequence, resolving an output_field for database functions and combined expressions may now crash with mixed types when using Value(). You will need to explicitly set the output_field in such cases.
    • The new QuerySet.alias() method allows creating reusable aliases for expressions that don’t need to be selected but are used for filtering, ordering, or as a part of complex expressions.
    • The new function allows filtering and ordering by specified database collations.
    • The field_name argument of QuerySet.in_bulk() now accepts distinct fields if there’s only one field specified in .
    • The new tzinfo parameter of the TruncDate and database functions allows truncating datetimes in a specific timezone.
    • The new db_collation argument for CharField and allows setting a database collation for the field.
    • Added the Random database function.
    • , F(), , and other expressions now allow using transforms. See Expressions can reference transforms for details.
    • The new durable argument for guarantees that changes made in the atomic block will be committed if the block exits without errors. A nested atomic block marked as durable will raise a RuntimeError.
    • Added the JSONObject database function.

    分页

    • The new method allows generating a page range with some of the values elided. If there are a large number of pages, this can be helpful for generating a reasonable number of page links in a template.

    请求和响应

    • Response headers are now stored in HttpResponse.headers. This can be used instead of the original dict-like interface of HttpResponse objects. Both interfaces will continue to be supported. See for details.
    • The new headers parameter of HttpResponse, , and TemplateResponse allows setting response on instantiation.

    安全

    • The SECRET_KEY setting is now checked for a valid value upon first access, rather than when settings are first loaded. This enables running management commands that do not rely on the SECRET_KEY without needing to provide a value. As a consequence of this, calling without providing a valid SECRET_KEY, and then going on to access settings.SECRET_KEY will now raise an ImproperlyConfigured exception.

    • The new Signer.sign_object() and Signer.unsign_object() methods allow signing complex data structures. See for more details.

      Also, signing.dumps() and become shortcuts for TimestampSigner.sign_object() and .

    序列化

    • The new JSONL serializer allows using the JSON Lines format with 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.

    信号

    • now logs exceptions.

    模板

    • floatformat template filter now allows using the g suffix to force grouping by the for the active locale.
    • Templates cached with Cached template loaders are now correctly reloaded in development.

    测试

    • Objects assigned to class attributes in are now isolated for each test method. Such objects are now required to support creating deep copies with copy.deepcopy(). Assigning objects which don’t support deepcopy() is deprecated and will be removed in Django 4.1.
    • now enables faulthandler by default. This can be disabled by using the option.
    • DiscoverRunner and the management command can now track timings, including database setup and total run time. This can be enabled by using the test --timing option.
    • now preserves the request query string when following 307 and 308 redirects.
    • The new TestCase.captureOnCommitCallbacks() method captures callback functions passed to in a list. This allows you to test such callbacks without using the slower TransactionTestCase.

    实用程序

    • 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.

    验证器

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

    数据库后端 API

    本节介绍了第三方数据库后端可能需要的更改。

    • 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_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 () 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 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.

    • 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 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.
    • no longer strips English stop words, such as 'a' or 'an'.
    • 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.

    杂项

    • 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().

    • The and intword template filters no longer depend on the 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 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 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 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 so that cleanups registered in the setUp() method are called before TestContextDecorator.disable().

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

    • The 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.

    • 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 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 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.

    • Assigning objects which don’t support creating deep copies with copy.deepcopy() to class attributes in 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 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 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.