August 1, 2018
Welcome to Django 2.1!
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 2.0 or earlier. 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 Upgrading Django to a newer version guide if you’re updating an existing project.
Django 2.1 supports Python 3.5, 3.6, and 3.7. Django 2.0 is the last version to support Python 3.4. We highly recommend and only officially support the latest release of each series.
A “view” permission is added to the model Meta.default_permissions. The new permissions will be
created automatically when running migrate.
This allows giving users read-only access to models in the admin.
ModelAdmin.has_view_permission() is new. The implementation is backwards
compatible in that there isn’t a need to assign the “view” permission to allow
users who have the “change” permission to edit objects.
There are a couple of backwards incompatible considerations.
django.contrib.admin¶ModelAdmin.search_fields now accepts any lookup such as
field__exact.
jQuery is upgraded from version 2.2.3 to 3.3.1.
The new ModelAdmin.delete_queryset() method allows customizing the
deletion process of the “delete selected objects” action.
You can now override the default admin site.
The new ModelAdmin.sortable_by attribute and
ModelAdmin.get_sortable_by() method allow limiting the columns that
can be sorted in the change list page.
The admin_order_field attribute for elements in
ModelAdmin.list_display may now be a query expression.
The new ModelAdmin.get_deleted_objects() method allows customizing
the deletion process of the delete view and the “delete selected” action.
The actions.html, change_list_results.html, date_hierarchy.html,
pagination.html, prepopulated_fields_js.html, search_form.html,
and submit_line.html templates can now be overridden per app or
per model (besides overridden
globally).
The admin change list and change form object tools can now be overridden
per app, per model, or globally
with change_list_object_tools.html and
change_form_object_tools.html templates.
InlineModelAdmin.has_add_permission() is now passed the parent object
as the second positional argument, obj.
Admin actions may now specify permissions to limit their availability to certain users.
django.contrib.auth¶createsuperuser now gives a prompt to allow bypassing the
AUTH_PASSWORD_VALIDATORS checks.
django.contrib.gis¶The new GEOSGeometry.buffer_with_style() method is a version of
buffer() that allows customizing the style of the
buffer.
OpenLayersWidget is now based on
OpenLayers 4.6.5 (previously 3.20.1).
django.contrib.sessions¶Added the SESSION_COOKIE_SAMESITE setting to set the SameSite
cookie flag on session cookies.
The local-memory cache backend now uses a least-recently-used (LRU) culling strategy rather than a pseudo-random one.
The new touch() method of the low-level
cache API updates the timeout of cache keys.
Added the CSRF_COOKIE_SAMESITE setting to set the SameSite
cookie flag on CSRF cookies.
The widget for ImageField now renders with the HTML attribute
accept="image/*".
Added the get_supported_language_variant()
function.
Untranslated strings for territorial language variants now use the
translations of the generic language. For example, untranslated pt_BR
strings use pt translations.
The new inspectdb --include-views option allows creating models
for database views.
The BaseCommand class now uses a custom help
formatter so that the standard options like --verbosity or --settings
appear last in the help output, giving a more prominent position to subclassed
command’s options.
Added support for serialization of functools.partialmethod objects.
To support frozen environments, migrations may be loaded from .pyc files.
Models can now use __init_subclass__() from PEP 487.
A BinaryField may now be set to editable=True if you wish to include
it in model forms.
A number of new text database functions are added:
Chr,
Left,
LPad,
LTrim,
Ord,
Repeat,
Replace,
Right,
RPad,
RTrim, and
Trim.
The new TruncWeek function truncates
DateField and
DateTimeField to the Monday of a week.
Query expressions can now be negated using a minus sign.
QuerySet.order_by() and distinct(*fields)
now support using field transforms.
BooleanField can now be null=True. This is
encouraged instead of NullBooleanField, which will
likely be deprecated in the future.
The new QuerySet.explain() method displays the database’s execution
plan of a queryset’s query.
QuerySet.raw() now supports prefetch_related().
Added the samesite argument to HttpResponse.set_cookie() to allow
setting the SameSite cookie flag.
The new as_attachment argument for FileResponse
sets the Content-Disposition header to make the browser ask if the user
wants to download the file. FileResponse also tries to set the
Content-Type and Content-Length headers where appropriate.
The new json_script filter safely outputs a Python object as JSON,
wrapped in a <script> tag, ready for use with JavaScript.
Added test Client support for 307 and 308 redirects.
The test Client now serializes a request data
dictionary as JSON if content_type='application/json'. You can customize
the JSON encoder with test client’s json_encoder parameter.
The new SimpleTestCase.assertWarnsMessage() method is a simpler
version of assertWarnsRegex().
This section describes changes that may be needed in third-party database backends.
To adhere to PEP 249, exceptions where a database doesn’t support a
feature are changed from NotImplementedError to
django.db.NotSupportedError.
Renamed the allow_sliced_subqueries database feature flag to
allow_sliced_subqueries_with_in.
DatabaseOperations.distinct_sql() now requires an additional params
argument and returns a tuple of SQL and parameters instead of a SQL string.
DatabaseFeatures.introspected_boolean_field_type is changed from a method
to a property.
django.contrib.gis¶Support for SpatiaLite 4.0 is removed.
The end of upstream support for MySQL 5.5 is December 2018. Django 2.1 supports MySQL 5.6 and higher.
The end of upstream support for PostgreSQL 9.3 is September 2018. Django 2.1 supports PostgreSQL 9.4 and higher.
BCryptPasswordHasher from the default PASSWORD_HASHERS setting¶If you used bcrypt with Django 1.4 or 1.5 (before BCryptSHA256PasswordHasher
was added in Django 1.6), you might have some passwords that use the
BCryptPasswordHasher hasher.
You can check if that’s the case like this:
from django.contrib.auth import get_user_model
User = get_user_model()
User.objects.filter(password__startswith='bcrypt$$')
If you want to continue to allow those passwords to be used, you’ll
have to define the PASSWORD_HASHERS setting (if you don’t already)
and include 'django.contrib.auth.hashers.BCryptPasswordHasher'.
wrap_label widget template context variable¶To fix the lack of <label> when using RadioSelect and
CheckboxSelectMultiple with MultiWidget, the wrap_label context
variable now appears as an attribute of each option. For example, in a custom
input_option.html template, change {% if wrap_label %} to
{% if widget.wrap_label %}.
With the new “view” permission, existing custom admin forms may raise errors
when a user doesn’t have the change permission because the form might access
nonexistent fields. Fix this by overriding ModelAdmin.get_form() and
checking if the user has the “change” permissions and returning the default
form if not:
class MyAdmin(admin.ModelAdmin):
def get_form(self, request, obj=None, **kwargs):
if not self.has_change_permission(request, obj):
return super().get_form(request, obj, **kwargs)
return CustomForm
If you have a custom permission with a codename of the form
view_<modelname>, the new view permission handling in the admin will allow
view access to the changelist and detail pages for those models. If this is
unwanted, you must change your custom permission codename.
The minimum supported version of mysqlclient is increased from 1.3.3 to
1.3.7.
Support for SQLite < 3.7.15 is removed.
The date format of Set-Cookie’s Expires directive is changed to
follow RFC 7231#section-7.1.1.1 instead of Netscape’s cookie standard.
Hyphens present in dates like Tue, 25-Dec-2018 22:26:13 GMT are removed.
This change should be merely cosmetic except perhaps for antiquated browsers
that don’t parse the new format.
allowed_hosts is now a required argument of private API
django.utils.http.is_safe_url().
The multiple attribute rendered by the
SelectMultiple widget now uses HTML5 boolean syntax
rather than XHTML’s multiple="multiple".
HTML rendered by form widgets no longer includes a closing slash on void
elements, e.g. <br>. This is incompatible within XHTML, although some
widgets already used aspects of HTML5 such as boolean attributes.
The value of SelectDateWidget’s empty options is
changed from 0 to an empty string, which mainly may require some adjustments
in tests that compare HTML.
User.has_usable_password() and the
is_password_usable() function no longer
return False if the password is None or an empty string, or if the
password uses a hasher that’s not in the PASSWORD_HASHERS setting.
This undocumented behavior was a regression in Django 1.6 and prevented users
with such passwords from requesting a password reset. Audit your code to
confirm that your usage of these APIs don’t rely on the old behavior.
Since migrations are now loaded from .pyc files, you might need to delete
them if you’re working in a mixed Python 2 and Python 3 environment.
Using None as a JSONField lookup
value now matches objects that have the specified key and a null value rather
than objects that don’t have the key.
The admin CSS class field-box is renamed to fieldBox to prevent
conflicts with the class given to model fields named “box”.
Since the admin’s actions.html, change_list_results.html,
date_hierarchy.html, pagination.html, prepopulated_fields_js.html,
search_form.html, and submit_line.html templates can now be
overridden per app or per model, you may need to rename existing templates
with those names that were written for a different purpose.
QuerySet.raw() now caches its results like regular querysets. Use
iterator() if you don’t want caching.
The database router allow_relation() method is called in more cases.
Improperly written routers may need to be updated accordingly.
Translations are no longer deactivated before running management commands. If your custom command requires translations to be deactivated (for example, to insert untranslated content into the database), use the new @no_translations decorator.
Management commands no longer allow the abbreviated forms of the
--settings and --pythonpath arguments.
The private django.db.models.sql.constants.QUERY_TERMS constant is
removed. The get_lookup()
and get_lookups() methods
of the Lookup Registration API may be
suitable alternatives. Compared to the QUERY_TERMS constant, they allow
your code to also account for any custom lookups that have been registered.
Compatibility with py-bcrypt is removed as it’s unmaintained. Use bcrypt instead.
The ForceRHR GIS function is deprecated in favor of the new
ForcePolygonCW function.
django.utils.http.cookie_date() is deprecated in favor of
http_date(), which follows the format of the latest
RFC.
{% load staticfiles %} and {% load admin_static %} are deprecated
in favor of {% load static %}, which works the same.
django.contrib.staticfiles.templatetags.static() is deprecated in favor
of django.templatetags.static.static().
Support for InlineModelAdmin.has_add_permission() methods that don’t
accept obj as the second positional argument will be removed in Django
3.0.
These features have reached the end of their deprecation cycle and are removed in Django 2.1. See Features deprecated in 1.11 for details, including how to remove usage of these features.
contrib.auth.views.login(), logout(), password_change(),
password_change_done(), password_reset(), password_reset_done(),
password_reset_confirm(), and password_reset_complete() are removed.
The extra_context parameter of contrib.auth.views.logout_then_login()
is removed.
django.test.runner.setup_databases() is removed.
django.utils.translation.string_concat() is removed.
django.core.cache.backends.memcached.PyLibMCCache no longer supports
passing pylibmc behavior settings as top-level attributes of OPTIONS.
The host parameter of django.utils.http.is_safe_url() is removed.
Silencing of exceptions raised while rendering the {% include %} template
tag is removed.
DatabaseIntrospection.get_indexes() is removed.
The authenticate() method of authentication backends requires request
as the first positional argument.
The django.db.models.permalink() decorator is removed.
The USE_ETAGS setting is removed. CommonMiddleware and
django.utils.cache.patch_response_headers() no longer set ETags.
The Model._meta.has_auto_field attribute is removed.
url()’s support for inline flags in regular expression groups ((?i),
(?L), (?m), (?s), and (?u)) is removed.
Support for Widget.render() methods without the renderer argument
is removed.
Dec 25, 2023