# Documentazione Django 6.0.7

# Note di rilascio di Django 1.9

1 Dicembre 2015

Welcome to Django 1.9!

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 1.8 or older versions. We’ve dropped some features that have reached the end of their deprecation cycle, and we’ve begun the deprecation process for some features.

See the Come aggiornare Django ad una nuova versione guide if you’re updating an existing project.

## Compatibilità con Python

Django 1.9 requires Python 2.7, 3.4, or 3.5. We highly recommend and only officially support the latest release of each series.

The Django 1.8 series is the last to support Python 3.2 and 3.3.

## What’s new in Django 1.9

### Performing actions after a transaction commit

The new `on_commit()` hook allows performing actions after a database transaction is successfully committed. This is useful for tasks such as sending notification emails, creating queued tasks, or invalidating caches.

This functionality from the django-transaction-hooks package has been integrated into Django.

### Password validation

Django now offers password validation to help prevent the usage of weak passwords by users. The validation is integrated in the included password change and reset forms and is simple to integrate in any other code. Validation is performed by one or more validators, configured in the new `AUTH_PASSWORD_VALIDATORS` setting.

Four validators are included in Django, which can enforce a minimum length, compare the password to the user’s attributes like their name, ensure passwords aren’t entirely numeric, or check against an included list of common passwords. You can combine multiple validators, and some validators have custom configuration options. For example, you can choose to provide a custom list of common passwords. Each validator provides a help text to explain its requirements to the user.

By default, no validation is performed and all passwords are accepted, so if you don’t set `AUTH_PASSWORD_VALIDATORS`, you will not see any change. In new projects created with the default `startproject` template, a simple set of validators is enabled. To enable basic validation in the included auth forms for your project, you could set, for example:

    AUTH_PASSWORD_VALIDATORS = [
        {
            "NAME": "django.contrib.auth.password_validation.UserAttributeSimilarityValidator",
        },
        {
            "NAME": "django.contrib.auth.password_validation.MinimumLengthValidator",
        },
        {
            "NAME": "django.contrib.auth.password_validation.CommonPasswordValidator",
        },
        {
            "NAME": "django.contrib.auth.password_validation.NumericPasswordValidator",
        },
    ]

See Password validation for more details.

### Permission mixins for class-based views

Django now ships with the mixins `AccessMixin`, `LoginRequiredMixin`, `PermissionRequiredMixin`, and `UserPassesTestMixin` to provide the functionality of the `django.contrib.auth.decorators` for class-based views. These mixins have been taken from, or are at least inspired by, the django-braces project.

There are a few differences between Django’s and `django-braces`' implementation, though:

- The `raise_exception` attribute can only be `True` or `False`. Custom exceptions or callables are not supported.

- The `handle_no_permission()` method does not take a `request` argument. The current request is available in `self.request`.

- The custom `test_func()` of `UserPassesTestMixin` does not take a `user` argument. The current user is available in `self.request.user`.

- The `permission_required` attribute supports a string (defining one permission) or a list/tuple of strings (defining multiple permissions) that need to be fulfilled to grant access.

- The new `permission_denied_message` attribute allows passing a message to the `PermissionDenied` exception.

### New styling for `contrib.admin`

The admin sports a modern, flat design with new SVG icons which look perfect on HiDPI screens. It still provides a fully-functional experience to YUI’s A-grade browsers. Older browser may experience varying levels of graceful degradation.

### Running tests in parallel

The `test` command now supports a `--parallel` option to run a project’s tests in multiple processes in parallel.

Each process gets its own database. You must ensure that different test cases don’t access the same resources. For instance, test cases that touch the filesystem should create a temporary directory for their own use.

This option is enabled by default for Django’s own test suite provided:

- the OS supports it (all but Windows)

- the database backend supports it (all the built-in backends but Oracle)

### Minor features

#### `django.contrib.admin`

- Admin views now have `model_admin` or `admin_site` attributes.

- The URL of the admin change view has been changed (was at `/admin/<app>/<model>/<pk>/` by default and is now at `/admin/<app>/<model>/<pk>/change/`). This should not affect your application unless you have hardcoded admin URLs. In that case, replace those links by reversing admin URLs instead. Note that the old URL still redirects to the new one for backwards compatibility, but it may be removed in a future version.

- `ModelAdmin.get_list_select_related()` was added to allow changing the `select_related()` values used in the admin’s changelist query based on the request.

- The `available_apps` context variable, which lists the available applications for the current user, has been added to the `AdminSite.each_context()` method.

- `AdminSite.empty_value_display` and `ModelAdmin.empty_value_display` were added to override the display of empty values in admin change list. You can also customize the value for each field.

- Added jQuery events when an inline form is added or removed on the change form page.

- The time picker widget includes a “6 p.m” option for consistency of having predefined options every 6 hours.

- JavaScript slug generation now supports Romanian characters.

#### `django.contrib.admindocs`

- The model section of the `admindocs` now also describes methods that take arguments, rather than ignoring them.

#### `django.contrib.auth`

- The default iteration count for the PBKDF2 password hasher has been increased by 20%. This backwards compatible change will not affect users who have subclassed `django.contrib.auth.hashers.PBKDF2PasswordHasher` to change the default value.

- The `BCryptSHA256PasswordHasher` will now update passwords if its `rounds` attribute is changed.

- `AbstractBaseUser` and `BaseUserManager` were moved to a new `django.contrib.auth.base_user` module so that they can be imported without including `django.contrib.auth` in `INSTALLED_APPS` (doing so raised a deprecation warning in older versions and is no longer supported in Django 1.9).

- The permission argument of `permission_required()` accepts all kinds of iterables, not only list and tuples.

- The new `PersistentRemoteUserMiddleware` makes it possible to use `REMOTE_USER` for setups where the header is only populated on login pages instead of every request in the session.

- The `django.contrib.auth.views.password_reset()` view accepts an `extra_email_context` parameter.

#### `django.contrib.contenttypes`

- It’s now possible to use `order_with_respect_to` with a `GenericForeignKey`.

#### `django.contrib.gis`

- All `GeoQuerySet` methods have been deprecated and replaced by equivalent database functions. As soon as the legacy methods have been replaced in your code, you should even be able to remove the special `GeoManager` from your GIS-enabled classes.

- The GDAL interface now supports instantiating file-based and in-memory GDALRaster objects from raw data. Setters for raster properties such as projection or pixel values have been added.

- For PostGIS users, the new `RasterField` allows storing GDALRaster objects. It supports automatic spatial index creation and reprojection when saving a model. It does not yet support spatial querying.

- The new `GDALRaster.warp()` method allows warping a raster by specifying target raster properties such as origin, width, height, or pixel size (among others).

- The new `GDALRaster.transform()` method allows transforming a raster into a different spatial reference system by specifying a target `srid`.

- The new `GeoIP2` class allows using MaxMind’s GeoLite2 databases which includes support for IPv6 addresses.

- The default OpenLayers library version included in widgets has been updated from 2.13 to 2.13.1.

#### `django.contrib.postgres`

- Added support for the `rangefield.contained_by` lookup for some built in fields which correspond to the range fields.

- Added `django.contrib.postgres.fields.JSONField`.

- Added PostgreSQL specific aggregation functions.

- Added the `TransactionNow` database function.

#### `django.contrib.sessions`

- The session model and `SessionStore` classes for the `db` and `cached_db` backends are refactored to allow a custom database session backend to build upon them. See Extending database-backed session engines for more details.

#### `django.contrib.sites`

- `get_current_site()` now handles the case where `request.get_host()` returns `domain:port`, e.g. `example.com:80`. If the lookup fails because the host does not match a record in the database and the host has a port, the port is stripped and the lookup is retried with the domain part only.

#### `django.contrib.syndication`

- Support for multiple enclosures per feed item has been added. If multiple enclosures are defined on a RSS feed, an exception is raised as RSS feeds, unlike Atom feeds, do not support multiple enclosures per feed item.

#### Cache

- `django.core.cache.backends.base.BaseCache` now has a `get_or_set()` method.

- `django.views.decorators.cache.never_cache()` now sends more persuasive headers (added `no-cache, no-store, must-revalidate` to `Cache-Control`) to better prevent caching. This was also added in Django 1.8.8.

#### CSRF

- The request header’s name used for CSRF authentication can be customized with `CSRF_HEADER_NAME`.

- The CSRF referer header is now validated against the `CSRF_COOKIE_DOMAIN` setting if set. See How it works for details.

- The new `CSRF_TRUSTED_ORIGINS` setting provides a way to allow cross-origin unsafe requests (e.g. `POST`) over HTTPS.

#### Database backends

- The PostgreSQL backend (`django.db.backends.postgresql_psycopg2`) is also available as `django.db.backends.postgresql`. The old name will continue to be available for backwards compatibility.

#### File Storage

- `Storage.get_valid_name()` is now called when the `upload_to` is a callable.

- `File` now has the `seekable()` method when using Python 3.

#### I Form

- `ModelForm` accepts the new `Meta` option `field_classes` to customize the type of the fields. See Overriding the default fields for details.

- You can now specify the order in which form fields are rendered with the `field_order` attribute, the `field_order` constructor argument , or the `order_fields()` method.

- A form prefix can be specified inside a form class, not only when instantiating a form. See Prefixes for forms for details.

- You can now specify keyword arguments that you want to pass to the constructor of forms in a formset.

- `SlugField` now accepts an `allow_unicode` argument to allow Unicode characters in slugs.

- `CharField` now accepts a `strip` argument to strip input data of leading and trailing whitespace. As this defaults to `True` this is different behavior from previous releases.

- Form fields now support the `disabled` argument, allowing the field widget to be displayed disabled by browsers.

- It’s now possible to customize bound fields by overriding a field’s `get_bound_field()` method.

#### Generic Views

- Class-based views generated using `as_view()` now have `view_class` and `view_initkwargs` attributes.

- `method_decorator()` can now be used with a list or tuple of decorators. It can also be used to decorate classes instead of methods.

#### Internationalization

- The `django.views.i18n.set_language()` view now properly redirects to translated URLs, when available.

- The `django.views.i18n.javascript_catalog()` view now works correctly if used multiple times with different configurations on the same page.

- The `django.utils.timezone.make_aware()` function gained an `is_dst` argument to help resolve ambiguous times during DST transitions.

- You can now use locale variants supported by gettext. These are usually used for languages which can be written in different scripts, for example Latin and Cyrillic (e.g. `be@latin`).

- Added the `django.views.i18n.json_catalog()` view to help build a custom client-side i18n library upon Django translations. It returns a JSON object containing a translations catalog, formatting settings, and a plural rule.

- Added the `name_translated` attribute to the object returned by the `get_language_info` template tag. Also added a corresponding template filter: `language_name_translated`.

- You can now run `compilemessages` from the root directory of your project and it will find all the app message files that were created by `makemessages`.

- `makemessages` now calls `xgettext` once per locale directory rather than once per translatable file. This speeds up localization builds.

- `blocktrans` supports assigning its output to a variable using `asvar`.

- Two new languages are available: Colombian Spanish and Scottish Gaelic.

#### Management Commands

- The new `sendtestemail` command lets you send a test email to easily confirm that email sending through Django is working.

- To increase the readability of the SQL code generated by `sqlmigrate`, the SQL code generated for each migration operation is preceded by the operation’s description.

- The `dumpdata` command output is now deterministically ordered. Moreover, when the `--output` option is specified, it also shows a progress bar in the terminal.

- The `createcachetable` command now has a `--dry-run` flag to print out the SQL rather than execute it.

- The `startapp` command creates an `apps.py` file. Since it doesn’t use `default_app_config` (a discouraged API), you must specify the app config’s path, e.g. `'polls.apps.PollsConfig'`, in `INSTALLED_APPS` for it to be used (instead of just `'polls'`).

- When using the PostgreSQL backend, the `dbshell` command can connect to the database using the password from your settings file (instead of requiring it to be manually entered).

- The `django` package may be run as a script, i.e. `python -m django`, which will behave the same as `django-admin`.

- Management commands that have the `--noinput` option now also take `--no-input` as an alias for that option.

#### Migrations

- Initial migrations are now marked with an `initial = True` class attribute which allows `migrate --fake-initial` to more easily detect initial migrations.

- Added support for serialization of `functools.partial` and `LazyObject` instances.

- When supplying `None` as a value in `MIGRATION_MODULES`, Django will consider the app an app without migrations.

- When applying migrations, the «Rendering model states» step that’s displayed when running migrate with verbosity 2 or higher now computes only the states for the migrations that have already been applied. The model states for migrations being applied are generated on demand, drastically reducing the amount of required memory.

  However, this improvement is not available when unapplying migrations and therefore still requires the precomputation and storage of the intermediate migration states.

  This improvement also requires that Django no longer supports mixed migration plans. Mixed plans consist of a list of migrations where some are being applied and others are being unapplied. This was never officially supported and never had a public API that supports this behavior.

- The `squashmigrations` command now supports specifying the starting migration from which migrations will be squashed.

#### Modelli

- `QuerySet.bulk_create()` now works on proxy models.

- Database configuration gained a `TIME_ZONE` option for interacting with databases that store datetimes in local time and don’t support time zones when `USE_TZ` is `True`.

- Added the `RelatedManager.set()` method to the related managers created by `ForeignKey`, `GenericForeignKey`, and `ManyToManyField`.

- The `add()` method on a reverse foreign key now has a `bulk` parameter to allow executing one query regardless of the number of objects being added rather than one query per object.

- Added the `keep_parents` parameter to `Model.delete()` to allow deleting only a child’s data in a model that uses multi-table inheritance.

- `Model.delete()` and `QuerySet.delete()` return the number of objects deleted.

- Added a system check to prevent defining both `Meta.ordering` and `order_with_respect_to` on the same model.

- `Date and time` lookups can be chained with other lookups (such as `exact`, `gt`, `lt`, etc.). For example: `Entry.objects.filter(pub_date__month__gt=6)`.

- Time lookups (hour, minute, second) are now supported by `TimeField` for all database backends. Support for backends other than SQLite was added but undocumented in Django 1.7.

- You can specify the `output_field` parameter of the `Avg` aggregate in order to aggregate over non-numeric columns, such as `DurationField`.

- Added the `date` lookup to `DateTimeField` to allow querying the field by only the date portion.

- Added the `Greatest` and `Least` database functions.

- Added the `Now` database function, which returns the current date and time.

- `Transform` is now a subclass of Func() which allows `Transform`s to be used on the right hand side of an expression, just like regular `Func`s. This allows registering some database functions like `Length`, `Lower`, and `Upper` as transforms.

- `SlugField` now accepts an `allow_unicode` argument to allow Unicode characters in slugs.

- Added support for referencing annotations in `QuerySet.distinct()`.

- `connection.queries` shows queries with substituted parameters on SQLite.

- Query expressions can now be used when creating new model instances using `save()`, `create()`, and `bulk_create()`.

#### Requests and Responses

- Unless `HttpResponse.reason_phrase` is explicitly set, it now is determined by the current value of `HttpResponse.status_code`. Modifying the value of `status_code` outside of the constructor will also modify the value of `reason_phrase`.

- The debug view now shows details of chained exceptions on Python 3.

- The default 40x error views now accept a second positional parameter, the exception that triggered the view.

- View error handlers now support `TemplateResponse`, commonly used with class-based views.

- Exceptions raised by the `render()` method are now passed to the `process_exception()` method of each middleware.

- Request middleware can now set `HttpRequest.urlconf` to `None` to revert any changes made by previous middleware and return to using the `ROOT_URLCONF`.

- The `DISALLOWED_USER_AGENTS` check in `CommonMiddleware` now raises a `PermissionDenied` exception as opposed to returning an `HttpResponseForbidden` so that `handler403` is invoked.

- Added `HttpRequest.get_port()` to fetch the originating port of the request.

- Added the `json_dumps_params` parameter to `JsonResponse` to allow passing keyword arguments to the `json.dumps()` call used to generate the response.

- The `BrokenLinkEmailsMiddleware` now ignores 404s when the referer is equal to the requested URL. To circumvent the empty referer check already implemented, some web bots set the referer to the requested URL.

#### Template

- Template tags created with the `simple_tag()` helper can now store results in a template variable by using the `as` argument.

- Added a `Context.setdefault()` method.

- The django.template logger was added and includes the following messages:

  - A `DEBUG` level message for missing context variables.

  - A `WARNING` level message for uncaught exceptions raised during the rendering of an `{% include %}` when debug mode is off (helpful since `{% include %}` silences the exception and returns an empty string).

- The `firstof` template tag supports storing the output in a variable using “as”.

- `Context.update()` can now be used as a context manager.

- Django template loaders can now extend templates recursively.

- The debug page template postmortem now include output from each engine that is installed.

- Debug page integration for custom template engines was added.

- The `DjangoTemplates` backend gained the ability to register libraries and builtins explicitly through the template `OPTIONS`.

- The `timesince` and `timeuntil` filters were improved to deal with leap years when given large time spans.

- The `include` tag now caches parsed templates objects during template rendering, speeding up reuse in places such as for loops.

#### Tests

- Added the `json()` method to test client responses to give access to the response body as JSON.

- Added the `force_login()` method to the test client. Use this method to simulate the effect of a user logging into the site while skipping the authentication and verification steps of `login()`.

#### URLs

- Regular expression lookaround assertions are now allowed in URL patterns.

- The application namespace can now be set using an `app_name` attribute on the included module or object. It can also be set by passing a 2-tuple of (<list of patterns>, <application namespace>) as the first argument to `include()`.

- System checks have been added for common URL pattern mistakes.

#### Validators

- Added `django.core.validators.int_list_validator()` to generate validators of strings containing integers separated with a custom character.

- `EmailValidator` now limits the length of domain name labels to 63 characters per RFC 1034.

- Added `validate_unicode_slug()` to validate slugs that may contain Unicode characters.

## Backwards incompatible changes in 1.9

Avvertimento

In addition to the changes outlined in this section, be sure to review the Features removed in 1.9 for the features that have reached the end of their deprecation cycle and therefore been removed. If you haven’t updated your code within the deprecation timeline for a given feature, its removal may appear as a backwards incompatible change.

### Database backend API

- A couple of new tests rely on the ability of the backend to introspect column defaults (returning the result as `Field.default`). You can set the `can_introspect_default` database feature to `False` if your backend doesn’t implement this. You may want to review the implementation on the backends that Django includes for reference (#24245).

- Registering a global adapter or converter at the level of the DB-API module to handle time zone information of `datetime` values passed as query parameters or returned as query results on databases that don’t support time zones is discouraged. It can conflict with other libraries.

  The recommended way to add a time zone to `datetime` values fetched from the database is to register a converter for `DateTimeField` in `DatabaseOperations.get_db_converters()`.

  The `needs_datetime_string_cast` database feature was removed. Database backends that set it must register a converter instead, as explained above.

- The `DatabaseOperations.value_to_db_<type>()` methods were renamed to `adapt_<type>field_value()` to mirror the `convert_<type>field_value()` methods.

- To use the new `date` lookup, third-party database backends may need to implement the `DatabaseOperations.datetime_cast_date_sql()` method.

- The `DatabaseOperations.time_extract_sql()` method was added. It calls the existing `date_extract_sql()` method. This method is overridden by the SQLite backend to add time lookups (hour, minute, second) to `TimeField`, and may be needed by third-party database backends.

- The `DatabaseOperations.datetime_cast_sql()` method (not to be confused with `DatabaseOperations.datetime_cast_date_sql()` mentioned above) has been removed. This method served to format dates on Oracle long before 1.0, but hasn’t been overridden by any core backend in years and hasn’t been called anywhere in Django’s code or tests.

- In order to support test parallelization, you must implement the `DatabaseCreation._clone_test_db()` method and set `DatabaseFeatures.can_clone_databases = True`. You may have to adjust `DatabaseCreation.get_test_db_clone_settings()`.

### Default settings that were tuples are now lists

The default settings in `django.conf.global_settings` were a combination of lists and tuples. All settings that were formerly tuples are now lists.

### `is_usable` attribute on template loaders is removed

Django template loaders previously required an `is_usable` attribute to be defined. If a loader was configured in the template settings and this attribute was `False`, the loader would be silently ignored. In practice, this was only used by the egg loader to detect if `setuptools` was installed. The `is_usable` attribute is now removed and the egg loader instead fails at runtime if `setuptools` is not installed.

### Related set direct assignment

Direct assignment of related objects in the ORM used to perform a `clear()` followed by a call to `add()`. This caused needlessly large data changes and prevented using the `m2m_changed` signal to track individual changes in many-to-many relations.

Direct assignment now relies on the new `set()` method on related managers which by default only processes changes between the existing related set and the one that’s newly assigned. The previous behavior can be restored by replacing direct assignment by a call to `set()` with the keyword argument `clear=True`.

`ModelForm`, and therefore `ModelAdmin`, internally rely on direct assignment for many-to-many relations and as a consequence now use the new behavior.

### Filesystem-based template loaders catch more specific exceptions

When using the `filesystem.Loader` or `app_directories.Loader` template loaders, earlier versions of Django raised a `TemplateDoesNotExist` error if a template source existed but was unreadable. This could happen under many circumstances, such as if Django didn’t have permissions to open the file, or if the template source was a directory. Now, Django only silences the exception if the template source does not exist. All other situations result in the original `IOError` being raised.

### HTTP redirects no longer forced to absolute URIs

Relative redirects are no longer converted to absolute URIs. RFC 2616 required the `Location` header in redirect responses to be an absolute URI, but it has been superseded by RFC 7231 which allows relative URIs in `Location`, recognizing the actual practice of user agents, almost all of which support them.

Consequently, the expected URLs passed to `assertRedirects` should generally no longer include the scheme and domain part of the URLs. For example, `self.assertRedirects(response, 'http://testserver/some-url/')` should be replaced by `self.assertRedirects(response, '/some-url/')` (unless the redirection specifically contained an absolute URL).

In the rare case that you need the old behavior (discovered with an ancient version of Apache with `mod_scgi` that interprets a relative redirect as an «internal redirect»), you can restore it by writing a custom middleware:

    class LocationHeaderFix(object):
        def process_response(self, request, response):
            if "Location" in response:
                response["Location"] = request.build_absolute_uri(response["Location"])
            return response

### Dropped support for PostgreSQL 9.0

Upstream support for PostgreSQL 9.0 ended in September 2015. As a consequence, Django 1.9 sets 9.1 as the minimum PostgreSQL version it officially supports.

### Dropped support for Oracle 11.1

Upstream support for Oracle 11.1 ended in August 2015. As a consequence, Django 1.9 sets 11.2 as the minimum Oracle version it officially supports.

### Bulk behavior of `add()` method of related managers

To improve performance, the `add()` methods of the related managers created by `ForeignKey` and `GenericForeignKey` changed from a series of `Model.save()` calls to a single `QuerySet.update()` call. The change means that `pre_save` and `post_save` signals aren’t sent anymore. You can use the `bulk=False` keyword argument to revert to the previous behavior.

### Template `LoaderOrigin` and `StringOrigin` are removed

In previous versions of Django, when a template engine was initialized with debug as `True`, an instance of `django.template.loader.LoaderOrigin` or `django.template.base.StringOrigin` was set as the origin attribute on the template object. These classes have been combined into `Origin` and is now always set regardless of the engine debug setting. For a minimal level of backwards compatibility, the old class names will be kept as aliases to the new `Origin` class until Django 2.0.

### Changes to the default logging configuration

To make it easier to write custom logging configurations, Django’s default logging configuration no longer defines `django.request` and `django.security` loggers. Instead, it defines a single `django` logger, filtered at the `INFO` level, with two handlers:

- `console`: filtered at the `INFO` level and only active if `DEBUG=True`.

- `mail_admins`: filtered at the `ERROR` level and only active if `DEBUG=False`.

If you aren’t overriding Django’s default logging, you should see minimal changes in behavior, but you might see some new logging to the `runserver` console, for example.

If you are overriding Django’s default logging, you should check to see how your configuration merges with the new defaults.

### `HttpRequest` details in error reporting

It was redundant to display the full details of the `HttpRequest` each time it appeared as a stack frame variable in the HTML version of the debug page and error email. Thus, the HTTP request will now display the same standard representation as other variables (`repr(request)`). As a result, the `ExceptionReporterFilter.get_request_repr()` method and the undocumented `django.http.build_request_repr()` function were removed.

The contents of the text version of the email were modified to provide a traceback of the same structure as in the case of AJAX requests. The traceback details are rendered by the `ExceptionReporter.get_traceback_text()` method.

### Removal of time zone aware global adapters and converters for datetimes

Django no longer registers global adapters and converters for managing time zone information on `datetime` values sent to the database as query parameters or read from the database in query results. This change affects projects that meet all the following conditions:

- The `USE_TZ` setting is `True`.

- The database is SQLite, MySQL, Oracle, or a third-party database that doesn’t support time zones. In doubt, you can check the value of `connection.features.supports_timezones`.

- The code queries the database outside of the ORM, typically with `cursor.execute(sql, params)`.

If you’re passing aware `datetime` parameters to such queries, you should turn them into naive datetimes in UTC:

    from django.utils import timezone

    param = timezone.make_naive(param, timezone.utc)

If you fail to do so, the conversion will be performed as in earlier versions (with a deprecation warning) up until Django 1.11. Django 2.0 won’t perform any conversion, which may result in data corruption.

If you’re reading `datetime` values from the results, they will be naive instead of aware. You can compensate as follows:

    from django.utils import timezone

    value = timezone.make_aware(value, timezone.utc)

You don’t need any of this if you’re querying the database through the ORM, even if you’re using `raw()` queries. The ORM takes care of managing time zone information.

### Template tag modules are imported when templates are configured

The `DjangoTemplates` backend now performs discovery on installed template tag modules when instantiated. This update enables libraries to be provided explicitly via the `'libraries'` key of `OPTIONS` when defining a `DjangoTemplates` backend. Import or syntax errors in template tag modules now fail early at instantiation time rather than when a template with a `{% load %}` tag is first compiled.

### `django.template.base.add_to_builtins()` is removed

Although it was a private API, projects commonly used `add_to_builtins()` to make template tags and filters available without using the `{% load %}` tag. This API has been formalized. Projects should now define built-in libraries via the `'builtins'` key of `OPTIONS` when defining a `DjangoTemplates` backend.

### `simple_tag` now wraps tag output in `conditional_escape`

In general, template tags do not autoescape their contents, and this behavior is documented. For tags like `inclusion_tag`, this is not a problem because the included template will perform autoescaping. For `assignment_tag()`, the output will be escaped when it is used as a variable in the template.

For the intended use cases of `simple_tag`, however, it is very easy to end up with incorrect HTML and possibly an XSS exploit. For example:

    @register.simple_tag(takes_context=True)
    def greeting(context):
        return "Hello {0}!".format(context["request"].user.first_name)

In older versions of Django, this will be an XSS issue because `user.first_name` is not escaped.

In Django 1.9, this is fixed: if the template context has `autoescape=True` set (the default), then `simple_tag` will wrap the output of the tag function with `conditional_escape()`.

To fix your `simple_tag`s, it is best to apply the following practices:

- Any code that generates HTML should use either the template system or `format_html()`.

- If the output of a `simple_tag` needs escaping, use `escape()` or `conditional_escape()`.

- If you are absolutely certain that you are outputting HTML from a trusted source (e.g. a CMS field that stores HTML entered by admins), you can mark it as such using `mark_safe()`.

Tags that follow these rules will be correct and safe whether they are run on Django 1.9+ or earlier.

### `Paginator.page_range`

`Paginator.page_range` is now an iterator instead of a list.

In versions of Django previous to 1.8, `Paginator.page_range` returned a `list` in Python 2 and a `range` in Python 3. Django 1.8 consistently returned a list, but an iterator is more efficient.

Existing code that depends on `list` specific features, such as indexing, can be ported by converting the iterator into a `list` using `list()`.

### Implicit `QuerySet` `__in` lookup removed

In earlier versions, queries such as:

    Model.objects.filter(related_id=RelatedModel.objects.all())

would implicitly convert to:

    Model.objects.filter(related_id__in=RelatedModel.objects.all())

resulting in SQL like `"related_id IN (SELECT id FROM ...)"`.

This implicit `__in` no longer happens so the «IN» SQL is now «=», and if the subquery returns multiple results, at least some databases will throw an error.

### `contrib.admin` browser support

The admin no longer supports Internet Explorer 8 and below, as these browsers have reached end-of-life.

CSS and images to support Internet Explorer 6 and 7 have been removed. PNG and GIF icons have been replaced with SVG icons, which are not supported by Internet Explorer 8 and earlier.

The jQuery library embedded in the admin has been upgraded from version 1.11.2 to 2.1.4. jQuery 2.x has the same API as jQuery 1.x, but does not support Internet Explorer 6, 7, or 8, allowing for better performance and a smaller file size. If you need to support IE8 and must also use the latest version of Django, you can override the admin’s copy of jQuery with your own by creating a Django application with this structure:

    app/static/admin/js/vendor/
        jquery.js
        jquery.min.js

### `SyntaxError` when installing Django `setuptools` 5.5.x

When installing Django 1.9 or 1.9.1 with `setuptools` 5.5.x, you’ll see:

    Compiling django/conf/app_template/apps.py ...
      File "django/conf/app_template/apps.py", line 4
        class {{ camel_case_app_name }}Config(AppConfig):
              ^
    SyntaxError: invalid syntax

    Compiling django/conf/app_template/models.py ...
      File "django/conf/app_template/models.py", line 1
        {{ unicode_literals }}from django.db import models
                                 ^
    SyntaxError: invalid syntax

It’s safe to ignore these errors (Django will still install just fine), but you can avoid them by upgrading `setuptools` to a more recent version. If you’re using pip, you can upgrade pip using `python -m pip install -U pip` which will also upgrade `setuptools`. This is resolved in later versions of Django as described in the Note di rilascio di Django 1.9.2.

### Miscellanea

- The jQuery static files in `contrib.admin` have been moved into a `vendor/jquery` subdirectory.

- The text displayed for null columns in the admin changelist `list_display` cells has changed from `(None)` (or its translated equivalent) to `-` (a dash).

- `django.http.responses.REASON_PHRASES` and `django.core.handlers.wsgi.STATUS_CODE_TEXT` have been removed. Use Python’s Standard Library instead: `http.client.responses` for Python 3 and httplib.responses for Python 2.

- `ValuesQuerySet` and `ValuesListQuerySet` have been removed.

- The `admin/base.html` template no longer sets `window.__admin_media_prefix__` or `window.__admin_utc_offset__`. Image references in JavaScript that used that value to construct absolute URLs have been moved to CSS for easier customization. The UTC offset is stored on a data attribute of the `<body>` tag.

- `CommaSeparatedIntegerField` validation has been refined to forbid values like `','`, `',1'`, and `'1,,2'`.

- Form initialization was moved from the `ProcessFormView.get()` method to the new `FormMixin.get_context_data()` method. This may be backwards incompatible if you have overridden the `get_context_data()` method without calling `super()`.

- Support for PostGIS 1.5 has been dropped.

- The `django.contrib.sites.models.Site.domain` field was changed to be `unique`.

- In order to enforce test isolation, database queries are not allowed by default in `SimpleTestCase` tests anymore. You can disable this behavior by setting the `allow_database_queries` class attribute to `True` on your test class.

- `ResolverMatch.app_name` was changed to contain the full namespace path in the case of nested namespaces. For consistency with `ResolverMatch.namespace`, the empty value is now an empty string instead of `None`.

- For security hardening, session keys must be at least 8 characters.

- Private function `django.utils.functional.total_ordering()` has been removed. It contained a workaround for a `functools.total_ordering()` bug in Python versions older than 2.7.3.

- XML serialization (either through `dumpdata` or the syndication framework) used to output any characters it received. Now if the content to be serialized contains any control characters not allowed in the XML 1.0 standard, the serialization will fail with a `ValueError`.

- `CharField` now strips input of leading and trailing whitespace by default. This can be disabled by setting the new `strip` argument to `False`.

- Template text that is translated and uses two or more consecutive percent signs, e.g. `"%%"`, may have a new `msgid` after `makemessages` is run (most likely the translation will be marked fuzzy). The new `msgid` will be marked `"#, python-format"`.

- If neither `request.current_app` nor `Context.current_app` are set, the `url` template tag will now use the namespace of the current request. Set `request.current_app` to `None` if you don’t want to use a namespace hint.

- The `SILENCED_SYSTEM_CHECKS` setting now silences messages of all levels. Previously, messages of `ERROR` level or higher were printed to the console.

- The `FlatPage.enable_comments` field is removed from the `FlatPageAdmin` as it’s unused by the application. If your project or a third-party app makes use of it, create a custom ModelAdmin to add it back.

- The return value of `setup_databases()` and the first argument of `teardown_databases()` changed. They used to be `(old_names, mirrors)` tuples. Now they’re just the first item, `old_names`.

- By default `LiveServerTestCase` attempts to find an available port in the 8081-8179 range instead of just trying port 8081.

- The system checks for `ModelAdmin` now check instances rather than classes.

- The private API to apply mixed migration plans has been dropped for performance reasons. Mixed plans consist of a list of migrations where some are being applied and others are being unapplied.

- The related model object descriptor classes in `django.db.models.fields.related` (private API) are moved from the `related` module to `related_descriptors` and renamed as follows:

  - `ReverseSingleRelatedObjectDescriptor` is `ForwardManyToOneDescriptor`

  - `SingleRelatedObjectDescriptor` is `ReverseOneToOneDescriptor`

  - `ForeignRelatedObjectsDescriptor` is `ReverseManyToOneDescriptor`

  - `ManyRelatedObjectsDescriptor` is `ManyToManyDescriptor`

- If you implement a custom `handler404` view, it must return a response with an HTTP 404 status code. Use `HttpResponseNotFound` or pass `status=404` to the `HttpResponse`. Otherwise, `APPEND_SLASH` won’t work correctly with `DEBUG=False`.

## Features deprecated in 1.9

### `assignment_tag()`

Django 1.4 added the `assignment_tag` helper to ease the creation of template tags that store results in a template variable. The `simple_tag()` helper has gained this same ability, making the `assignment_tag` obsolete. Tags that use `assignment_tag` should be updated to use `simple_tag`.

### `{% cycle %}` syntax with comma-separated arguments

The `cycle` tag supports an inferior old syntax from previous Django versions:

    {% cycle row1,row2,row3 %}

Its parsing caused bugs with the current syntax, so support for the old syntax will be removed in Django 1.10 following an accelerated deprecation.

### `ForeignKey` and `OneToOneField` `on_delete` argument

In order to increase awareness about cascading model deletion, the `on_delete` argument of `ForeignKey` and `OneToOneField` will be required in Django 2.0.

Update models and existing migrations to explicitly set the argument. Since the default is `models.CASCADE`, add `on_delete=models.CASCADE` to all `ForeignKey` and `OneToOneField`s that don’t use a different option. You can also pass it as the second positional argument if you don’t care about compatibility with older versions of Django.

### `Field.rel` changes

`Field.rel` and its methods and attributes have changed to match the related fields API. The `Field.rel` attribute is renamed to `remote_field` and many of its methods and attributes are either changed or renamed.

The aim of these changes is to provide a documented API for relation fields.

### `GeoManager` and `GeoQuerySet` custom methods

All custom `GeoQuerySet` methods (`area()`, `distance()`, `gml()`, …) have been replaced by equivalent geographic expressions in annotations (see in new features). Hence the need to set a custom `GeoManager` to GIS-enabled models is now obsolete. As soon as your code doesn’t call any of the deprecated methods, you can simply remove the `objects = GeoManager()` lines from your models.

### Template loader APIs have changed

Django template loaders have been updated to allow recursive template extending. This change necessitated a new template loader API. The old `load_template()` and `load_template_sources()` methods are now deprecated. Details about the new API can be found in the template loader documentation.

### Passing a 3-tuple or an `app_name` to `include()`

The instance namespace part of passing a tuple as an argument to `include()` has been replaced by passing the `namespace` argument to `include()`. For example:

    polls_patterns = [
        url(...),
    ]

    urlpatterns = [
        url(r"^polls/", include((polls_patterns, "polls", "author-polls"))),
    ]

becomes:

    polls_patterns = (
        [
            url(...),
        ],
        "polls",
    )  # 'polls' is the app_name

    urlpatterns = [
        url(r"^polls/", include(polls_patterns, namespace="author-polls")),
    ]

The `app_name` argument to `include()` has been replaced by passing a 2-tuple (as above), or passing an object or module with an `app_name` attribute (as below). If the `app_name` is set in this new way, the `namespace` argument is no longer required. It will default to the value of `app_name`. For example, the URL patterns in the tutorial are changed from:

`mysite/urls.py`

    urlpatterns = [url(r"^polls/", include("polls.urls", namespace="polls")), ...]

to:

`mysite/urls.py`

    urlpatterns = [
        url(r"^polls/", include("polls.urls")),  # 'namespace="polls"' removed
        ...,
    ]

`polls/urls.py`

    app_name = "polls"  # added
    urlpatterns = [...]

This change also means that the old way of including an `AdminSite` instance is deprecated. Instead, pass `admin.site.urls` directly to `django.conf.urls.url()`:

`urls.py`

    from django.conf.urls import url
    from django.contrib import admin

    urlpatterns = [
        url(r"^admin/", admin.site.urls),
    ]

### URL application namespace required if setting an instance namespace

In the past, an instance namespace without an application namespace would serve the same purpose as the application namespace, but it was impossible to reverse the patterns if there was an application namespace with the same name. Includes that specify an instance namespace require that the included URLconf sets an application namespace.

### `current_app` parameter to `contrib.auth` views

All views in `django.contrib.auth.views` have the following structure:

    def view(request, ..., current_app=None, ...):

        ...

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)

As of Django 1.8, `current_app` is set on the `request` object. For consistency, these views will require the caller to set `current_app` on the `request` instead of passing it in a separate argument.

### `django.contrib.gis.geoip`

The `django.contrib.gis.geoip2` module supersedes `django.contrib.gis.geoip`. The new module provides a similar API except that it doesn’t provide the legacy GeoIP-Python API compatibility methods.

### Miscellanea

- The `weak` argument to `django.dispatch.signals.Signal.disconnect()` has been deprecated as it has no effect.

- The `check_aggregate_support()` method of `django.db.backends.base.BaseDatabaseOperations` has been deprecated and will be removed in Django 2.0. The more general `check_expression_support()` should be used instead.

- `django.forms.extras` is deprecated. You can find `SelectDateWidget` in `django.forms.widgets` (or simply `django.forms`) instead.

- Private API `django.db.models.fields.add_lazy_relation()` is deprecated.

- The `django.contrib.auth.tests.utils.skipIfCustomUser()` decorator is deprecated. With the test discovery changes in Django 1.6, the tests for `django.contrib` apps are no longer run as part of the user’s project. Therefore, the `@skipIfCustomUser` decorator is no longer needed to decorate tests in `django.contrib.auth`.

- If you customized some error handlers, the view signatures with only one request parameter are deprecated. The views should now also accept a second `exception` positional parameter.

- The `django.utils.feedgenerator.Atom1Feed.mime_type` and `django.utils.feedgenerator.RssFeed.mime_type` attributes are deprecated in favor of `content_type`.

- `Signer` now issues a warning if an invalid separator is used. This will become an exception in Django 1.10.

- `django.db.models.Field._get_val_from_obj()` is deprecated in favor of `Field.value_from_object()`.

- `django.template.loaders.eggs.Loader` is deprecated as distributing applications as eggs is not recommended.

- The `callable_obj` keyword argument to `SimpleTestCase.assertRaisesMessage()` is deprecated. Pass the callable as a positional argument instead.

- The `allow_tags` attribute on methods of `ModelAdmin` has been deprecated. Use `format_html()`, `format_html_join()`, or `mark_safe()` when constructing the method’s return value instead.

- The `enclosure` keyword argument to `SyndicationFeed.add_item()` is deprecated. Use the new `enclosures` argument which accepts a list of `Enclosure` objects instead of a single one.

- The `django.template.loader.LoaderOrigin` and `django.template.base.StringOrigin` aliases for `django.template.base.Origin` are deprecated.

## Features removed in 1.9

These features have reached the end of their deprecation cycle and are removed in Django 1.9. See Features deprecated in 1.7 for details, including how to remove usage of these features.

- `django.utils.dictconfig` is removed.

- `django.utils.importlib` is removed.

- `django.utils.tzinfo` is removed.

- `django.utils.unittest` is removed.

- The `syncdb` command is removed.

- `django.db.models.signals.pre_syncdb` and `django.db.models.signals.post_syncdb` is removed.

- Support for `allow_syncdb` on database routers is removed.

- Automatic syncing of apps without migrations is removed. Migrations are compulsory for all apps unless you pass the `migrate --run-syncdb` option.

- The SQL management commands for apps without migrations, `sql`, `sqlall`, `sqlclear`, `sqldropindexes`, and `sqlindexes`, are removed.

- Support for automatic loading of `initial_data` fixtures and initial SQL data is removed.

- All models need to be defined inside an installed application or declare an explicit `app_label`. Furthermore, it isn’t possible to import them before their application is loaded. In particular, it isn’t possible to import models inside the root package of an application.

- The model and form `IPAddressField` is removed. A stub field remains for compatibility with historical migrations.

- `AppCommand.handle_app()` is no longer supported.

- `RequestSite` and `get_current_site()` are no longer importable from `django.contrib.sites.models`.

- FastCGI support via the `runfcgi` management command is removed.

- `django.utils.datastructures.SortedDict` is removed.

- `ModelAdmin.declared_fieldsets` is removed.

- The `util` modules that provided backwards compatibility are removed:

  - `django.contrib.admin.util`

  - `django.contrib.gis.db.backends.util`

  - `django.db.backends.util`

  - `django.forms.util`

- `ModelAdmin.get_formsets` is removed.

- The backward compatible shims introduced to rename the `BaseMemcachedCache._get_memcache_timeout()` method to `get_backend_timeout()` is removed.

- The `--natural` and `-n` options for `dumpdata` are removed.

- The `use_natural_keys` argument for `serializers.serialize()` is removed.

- Private API `django.forms.forms.get_declared_fields()` is removed.

- The ability to use a `SplitDateTimeWidget` with `DateTimeField` is removed.

- The `WSGIRequest.REQUEST` property is removed.

- The class `django.utils.datastructures.MergeDict` is removed.

- The `zh-cn` and `zh-tw` language codes are removed.

- The internal `django.utils.functional.memoize()` is removed.

- `django.core.cache.get_cache` is removed.

- `django.db.models.loading` is removed.

- Passing callable arguments to querysets is no longer possible.

- `BaseCommand.requires_model_validation` is removed in favor of `requires_system_checks`. Admin validators is replaced by admin checks.

- The `ModelAdmin.validator_class` and `default_validator_class` attributes are removed.

- `ModelAdmin.validate()` is removed.

- `django.db.backends.DatabaseValidation.validate_field` is removed in favor of the `check_field` method.

- The `validate` management command is removed.

- `django.utils.module_loading.import_by_path` is removed in favor of `django.utils.module_loading.import_string`.

- `ssi` and `url` template tags are removed from the `future` template tag library.

- `django.utils.text.javascript_quote()` is removed.

- Database test settings as independent entries in the database settings, prefixed by `TEST_`, are no longer supported.

- The `cache_choices` option to `ModelChoiceField` and `ModelMultipleChoiceField` is removed.

- The default value of the `RedirectView.permanent` attribute has changed from `True` to `False`.

- `django.contrib.sitemaps.FlatPageSitemap` is removed in favor of `django.contrib.flatpages.sitemaps.FlatPageSitemap`.

- Private API `django.test.utils.TestTemplateLoader` is removed.

- The `django.contrib.contenttypes.generic` module is removed.