Django 2.1 release notes¶
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 How to upgrade Django to a newer version guide if you’re updating an existing project.
Python compatibility¶
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.
What’s new in Django 2.1¶
Model “view” permission¶
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.
Minor features¶
django.contrib.admin
¶
ModelAdmin.search_fields
now accepts any lookup such asfield__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 andModelAdmin.get_sortable_by()
method allow limiting the columns that can be sorted in the change list page.The
admin_order_field
attribute for elements inModelAdmin.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
, andsubmit_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
andchange_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 theAUTH_PASSWORD_VALIDATORS
checks.
django.contrib.gis
¶
The new
GEOSGeometry.buffer_with_style()
method is a version ofbuffer()
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 theSameSite
cookie flag on session cookies.
Cache¶
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.
CSRF¶
Added the
CSRF_COOKIE_SAMESITE
setting to set theSameSite
cookie flag on CSRF cookies.
Forms¶
The widget for
ImageField
now renders with the HTML attributeaccept="image/*"
.
Internationalization¶
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 usept
translations.
Management Commands¶
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.
Migrations¶
Added support for serialization of
functools.partialmethod
objects.To support frozen environments, migrations may be loaded from
.pyc
files.
Models¶
Models can now use
__init_subclass__()
from PEP 487.A
BinaryField
may now be set toeditable=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
, andTrim
.The new
TruncWeek
function truncatesDateField
andDateTimeField
to the Monday of a week.Query expressions can now be negated using a minus sign.
QuerySet.order_by()
anddistinct(*fields)
now support using field transforms.BooleanField
can now benull=True
. This is encouraged instead ofNullBooleanField
, 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 supportsprefetch_related()
.
Requests and Responses¶
Added the
samesite
argument toHttpResponse.set_cookie()
to allow setting theSameSite
cookie flag.The new
as_attachment
argument forFileResponse
sets theContent-Disposition
header to make the browser ask if the user wants to download the file.FileResponse
also tries to set theContent-Type
andContent-Length
headers where appropriate.
Templates¶
The new
json_script
filter safely outputs a Python object as JSON, wrapped in a<script>
tag, ready for use with JavaScript.
Tests¶
Added test
Client
support for 307 and 308 redirects.The test
Client
now serializes a request data dictionary as JSON ifcontent_type='application/json'
. You can customize the JSON encoder with test client’sjson_encoder
parameter.The new
SimpleTestCase.assertWarnsMessage()
method is a simpler version ofassertWarnsRegex()
.
Backwards incompatible changes in 2.1¶
Database backend API¶
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
todjango.db.NotSupportedError
.Renamed the
allow_sliced_subqueries
database feature flag toallow_sliced_subqueries_with_in
.DatabaseOperations.distinct_sql()
now requires an additionalparams
argument and returns a tuple of SQL and parameters instead of an 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.
Dropped support for MySQL 5.5¶
The end of upstream support for MySQL 5.5 is December 2018. Django 2.1 supports MySQL 5.6 and higher.
Dropped support for PostgreSQL 9.3¶
The end of upstream support for PostgreSQL 9.3 is September 2018. Django 2.1 supports PostgreSQL 9.4 and higher.
Removed 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'
.
Moved 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 %}
.
Considerations for the new model “view” permission¶
Custom admin forms need to take the view-only case into account¶
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
New default view permission could allow unwanted access to admin views¶
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.
Miscellaneous¶
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
’sExpires
directive is changed to follow RFC 7231 Section 7.1.1.1 instead of Netscape’s cookie standard. Hyphens present in dates likeTue, 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 APIdjango.utils.http.is_safe_url()
.The
multiple
attribute rendered by theSelectMultiple
widget now uses HTML5 boolean syntax rather than XHTML’smultiple="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 theis_password_usable()
function no longer returnFalse
if the password isNone
or an empty string, or if the password uses a hasher that’s not in thePASSWORD_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 adjango.contrib.postgres.fields.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 tofieldBox
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
, andsubmit_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. Useiterator()
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. Theget_lookup()
andget_lookups()
methods of the Lookup Registration API may be suitable alternatives. Compared to theQUERY_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.
Features deprecated in 2.1¶
Miscellaneous¶
The
ForceRHR
GIS function is deprecated in favor of the newForcePolygonCW
function.django.utils.http.cookie_date()
is deprecated in favor ofhttp_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 ofdjango.templatetags.static.static()
.Support for
InlineModelAdmin.has_add_permission()
methods that don’t acceptobj
as the second positional argument will be removed in Django 3.0.
Features removed in 2.1¶
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()
, andpassword_reset_complete()
are removed.The
extra_context
parameter ofcontrib.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 passingpylibmc
behavior settings as top-level attributes ofOPTIONS
.The
host
parameter ofdjango.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 requiresrequest
as the first positional argument.The
django.db.models.permalink()
decorator is removed.The
USE_ETAGS
setting is removed.CommonMiddleware
anddjango.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 therenderer
argument is removed.