Django 3.0 release notes | Django documentation (2024)

MariaDB support¶

Django now officially supports MariaDB 10.1 andhigher. See MariaDB notes for more details.

ASGI support¶

Django 3.0 begins our journey to making Django fully async-capable by providingsupport for running as an ASGI application.

This is in addition to our existing WSGI support. Django intends to supportboth for the foreseeable future. Async features will only be available toapplications that run under ASGI, however.

At this stage async support only applies to the outer ASGI application.Internally everything remains synchronous. Asynchronous middleware, views, etc.are not yet supported. You can, however, use ASGI middleware around Django’sapplication, allowing you to combine Django with other ASGI frameworks.

There is no need to switch your applications over unless you want to startexperimenting with asynchronous code, but we havedocumentation on deploying with ASGI ifyou want to learn more.

Note that as a side-effect of this change, Django is now aware of asynchronousevent loops and will block you calling code marked as “async unsafe” - such asORM operations - from an asynchronous context. If you were using Django fromasync code before, this may trigger if you were doing it incorrectly. If yousee a SynchronousOnlyOperation error, then closely examine your code andmove any database operations to be in a synchronous child thread.

Exclusion constraints on PostgreSQL¶

The new ExclusionConstraint classenable adding exclusion constraints on PostgreSQL. Constraints are added tomodels using theMeta.constraints option.

Filter expressions¶

Expressions that output BooleanField may now beused directly in QuerySet filters, without having to first annotate andthen filter against the annotation.

Enumerations for model field choices¶

Custom enumeration types TextChoices, IntegerChoices, and Choicesare now available as a way to define Field.choices. TextChoicesand IntegerChoices types are provided for text and integer fields. TheChoices class allows defining a compatible enumeration for other concretedata types. These custom enumeration types support human-readable labels thatcan be translated and accessed via a property on the enumeration or itsmembers. See Enumeration types for moredetails and examples.

Minor features¶

Model.save() when providing a default for the primary key¶

Model.save() no longer attempts to find a row when saving a newModel instance and a default value for the primary key is provided, andalways performs a single INSERT query. In older Django versions,Model.save() performed either an INSERT or an UPDATE based onwhether or not the row exists.

This makes calling Model.save() while providing a default primary key valueequivalent to passing force_insert=True tomodel’s save(). Attempts to use a new Model instance to update anexisting row will result in an IntegrityError.

In order to update an existing model for a specific primary key value, use theupdate_or_create() method orQuerySet.filter(pk=…).update(…) instead. For example:

>>> MyModel.objects.update_or_create(pk=existing_pk, defaults={"name": "new name"})>>> MyModel.objects.filter(pk=existing_pk).update(name="new name")

Database backend API¶

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

• The second argument of DatabaseIntrospection.get_geometry_type() is nowthe row description instead of the column name.
• DatabaseIntrospection.get_field_type() may no longer return tuples.
• If the database can create foreign keys in the same SQL statement that adds afield, add SchemaEditor.sql_create_column_inline_fk with the appropriateSQL; otherwise, set DatabaseFeatures.can_create_inline_fk = False.
• DatabaseFeatures.can_return_id_from_insert andcan_return_ids_from_bulk_insert are renamed tocan_return_columns_from_insert and can_return_rows_from_bulk_insert.
• Database functions now handle datetime.timezone formats when createdusing datetime.timedelta instances (e.g.timezone(timedelta(hours=5)), which would output 'UTC+05:00').Third-party backends should handle this format when preparingDateTimeField in datetime_cast_date_sql(),datetime_extract_sql(), etc.
• Entries for AutoField, BigAutoField, and SmallAutoField are addedto DatabaseOperations.integer_field_ranges to support the integer rangevalidators on these field types. Third-party backends may need to customizethe default entries.
• DatabaseOperations.fetch_returned_insert_id() is replaced byfetch_returned_insert_columns() which returns a list of values returnedby the INSERT … RETURNING statement, instead of a single value.
• DatabaseOperations.return_insert_id() is replaced byreturn_insert_columns() that accepts a fieldsargument, which is an iterable of fields to be returned after insert. Usuallythis is only the auto-generated primary key.

django.contrib.admin¶

• Admin’s model history change messages now prefers more readable field labelsinstead of field names.

django.contrib.gis¶

• Support for PostGIS 2.1 is removed.
• Support for SpatiaLite 4.1 and 4.2 is removed.
• Support for GDAL 1.11 and GEOS 3.4 is removed.

Dropped support for PostgreSQL 9.4¶

Upstream support for PostgreSQL 9.4 ends in December 2019. Django 3.0 supportsPostgreSQL 9.5 and higher.

Dropped support for Oracle 12.1¶

Upstream support for Oracle 12.1 ends in July 2021. Django 2.2 will besupported until April 2022. Django 3.0 officially supports Oracle 12.2 and 18c.

Removed private Python 2 compatibility APIs¶

While Python 2 support was removed in Django 2.0, some private APIs weren’tremoved from Django so that third party apps could continue using them untilthe Python 2 end-of-life.

Since we expect apps to drop Python 2 compatibility when adding support forDjango 3.0, we’re removing these APIs at this time.

• django.test.utils.str_prefix() - Strings don’t have ‘u’ prefixes inPython 3.
• django.test.utils.patch_logger() - Useunittest.TestCase.assertLogs() instead.
• django.utils.lru_cache.lru_cache() - Alias offunctools.lru_cache().
• django.utils.decorators.available_attrs() - This function returnsfunctools.WRAPPER_ASSIGNMENTS.
• django.utils.decorators.ContextDecorator - Alias ofcontextlib.ContextDecorator.
• django.utils._os.abspathu() - Alias of os.path.abspath().
• django.utils._os.upath() and npath() - These functions do nothing onPython 3.
• django.utils.six - Remove usage of this vendored library or switch tosix.
• django.utils.encoding.python_2_unicode_compatible() - Alias ofsix.python_2_unicode_compatible().
• django.utils.functional.curry() - Use functools.partial() orfunctools.partialmethod. See5b1c389603a353625ae1603ba345147356336afb.
• django.utils.safestring.SafeBytes - Unused since Django 2.0.

New default value for the FILE_UPLOAD_PERMISSIONS setting¶

In older versions, the FILE_UPLOAD_PERMISSIONS setting defaults toNone. With the default FILE_UPLOAD_HANDLERS, this results inuploaded files having different permissions depending on their size and whichupload handler is used.

FILE_UPLOAD_PERMISSIONS now defaults to 0o644 to avoid thisinconsistency.

New default values for security settings¶

To make Django projects more secure by default, some security settings now havemore secure default values:

• X_FRAME_OPTIONS now defaults to 'DENY'.
• SECURE_CONTENT_TYPE_NOSNIFF now defaults to True.

See the What’s New Security section above formore details on these changes.

Miscellaneous¶

• ContentType.__str__() now includes the model’s app_label todisambiguate models with the same name in different apps.
• Because accessing the language in the session rather than in the cookie isdeprecated, LocaleMiddleware no longer looks for the user’s language inthe session and django.contrib.auth.logout() no longer preserves thesession’s language after logout.
• django.utils.html.escape() now uses html.escape() to escape HTML.This converts ' to ' instead of the previous equivalent decimalcode '.
• The django-admin test -k option now works as the unittest-k option rather than as a shortcut for --keepdb.
• Support for pywatchman < 1.2.0 is removed.
• urlencode() now encodes iterable values as they arewhen doseq=False, rather than iterating them, bringing it into line withthe standard library urllib.parse.urlencode() function.
• intword template filter now translates 1.0 as a singular phrase andall other numeric values as plural. This may be incorrect for some languages.
• Assigning a value to a model’s ForeignKey orOneToOneField '_id' attribute now unsets thecorresponding field. Accessing the field afterward will result in a query.
• patch_vary_headers() now handles an asterisk'*' according to RFC 7231#section-7.1.4, i.e. if a list of headerfield names contains an asterisk, then the Vary header will consist of asingle asterisk '*'.
• On MySQL 8.0.16+, PositiveIntegerField and PositiveSmallIntegerFieldnow include a check constraint to prevent negative values in the database.
• alias=None is added to the signature ofExpression.get_group_by_cols().
• RegexPattern, used by re_path(), no longer returnskeyword arguments with None values to be passed to the view for theoptional named groups that are missing.

django.utils.encoding.force_text() and smart_text()¶

The smart_text() and force_text() aliases (since Django 2.0) ofsmart_str() and force_str() are deprecated. Ignore this deprecation ifyour code supports Python 2 as the behavior of smart_str() andforce_str() is different there.

Miscellaneous¶

• django.utils.http.urlquote(), urlquote_plus(), urlunquote(), andurlunquote_plus() are deprecated in favor of the functions that they’realiases for: urllib.parse.quote(), quote_plus(),unquote(), and unquote_plus().
• django.utils.translation.ugettext(), ugettext_lazy(),ugettext_noop(), ungettext(), and ungettext_lazy() are deprecatedin favor of the functions that they’re aliases for:django.utils.translation.gettext(),gettext_lazy(),gettext_noop(),ngettext(), andngettext_lazy().
• To limit creation of sessions and hence favor some caching strategies,django.views.i18n.set_language() will stop setting the user’s languagein the session in Django 4.0. Since Django 2.1, the language is always storedin the LANGUAGE_COOKIE_NAME cookie.
• django.utils.text.unescape_entities() is deprecated in favor ofhtml.unescape(). Note that unlike unescape_entities(),html.unescape() evaluates lazy strings immediately.
• To avoid possible confusion as to effective scope, the private internalutility is_safe_url() is renamed tourl_has_allowed_host_and_scheme(). That a URL has an allowed host andscheme doesn’t in general imply that it’s “safe”. It may still be quotedincorrectly, for example. Ensure to also useiri_to_uri() on the path component of untrustedURLs.