Refs #15902 -- Stopped set_language() storing user's language in the session.

Per deprecation timeline.

8 files changed, 15 insertions, 92 deletions

diff --git a/django/contrib/sessions/backends/base.py b/django/contrib/sessions/backends/base.py
index 0f06b23e93..143c08fbef 100644
--- a/django/contrib/sessions/backends/base.py
+++ b/django/contrib/sessions/backends/base.py
@@ -1,7 +1,6 @@
 import base64
 import logging
 import string
-import warnings
 from datetime import datetime, timedelta
 
 from django.conf import settings
@@ -12,9 +11,7 @@ from django.utils import timezone
 from django.utils.crypto import (
     constant_time_compare, get_random_string, salted_hmac,
 )
-from django.utils.deprecation import RemovedInDjango40Warning
 from django.utils.module_loading import import_string
-from django.utils.translation import LANGUAGE_SESSION_KEY
 
 # session_key should not be case sensitive because some backends can store it
 # on case insensitive file systems.
@@ -55,13 +52,6 @@ class SessionBase:
         return key in self._session
 
     def __getitem__(self, key):
-        if key == LANGUAGE_SESSION_KEY:
-            warnings.warn(
-                'The user language will no longer be stored in '
-                'request.session in Django 4.0. Read it from '
-                'request.COOKIES[settings.LANGUAGE_COOKIE_NAME] instead.',
-                RemovedInDjango40Warning, stacklevel=2,
-            )
         return self._session[key]
 
     def __setitem__(self, key, value):
diff --git a/django/utils/translation/__init__.py b/django/utils/translation/__init__.py
index 8e6b8ec0f8..aa5cd33f5b 100644
--- a/django/utils/translation/__init__.py
+++ b/django/utils/translation/__init__.py
@@ -17,11 +17,8 @@ __all__ = [
     'ngettext', 'ngettext_lazy',
     'pgettext', 'pgettext_lazy',
     'npgettext', 'npgettext_lazy',
-    'LANGUAGE_SESSION_KEY',
 ]
 
-LANGUAGE_SESSION_KEY = '_language'
-
 
 class TranslatorCommentWarning(SyntaxWarning):
     pass
diff --git a/django/views/i18n.py b/django/views/i18n.py
index d6a29eb8f9..ecb30a45f1 100644
--- a/django/views/i18n.py
+++ b/django/views/i18n.py
@@ -11,9 +11,7 @@ from django.template import Context, Engine
 from django.urls import translate_url
 from django.utils.formats import get_format
 from django.utils.http import url_has_allowed_host_and_scheme
-from django.utils.translation import (
-    LANGUAGE_SESSION_KEY, check_for_language, get_language,
-)
+from django.utils.translation import check_for_language, get_language
 from django.utils.translation.trans_real import DjangoTranslation
 from django.views.generic import View
 
@@ -57,10 +55,6 @@ def set_language(request):
                 next_trans = translate_url(next_url, lang_code)
                 if next_trans != next_url:
                     response = HttpResponseRedirect(next_trans)
-            if hasattr(request, 'session'):
-                # Storing the language in the session is deprecated.
-                # (RemovedInDjango40Warning)
-                request.session[LANGUAGE_SESSION_KEY] = lang_code
             response.set_cookie(
                 settings.LANGUAGE_COOKIE_NAME, lang_code,
                 max_age=settings.LANGUAGE_COOKIE_AGE,
diff --git a/docs/ref/utils.txt b/docs/ref/utils.txt
index b04e1196d4..52c5101e9f 100644
--- a/docs/ref/utils.txt
+++ b/docs/ref/utils.txt
@@ -1099,13 +1099,3 @@ For a complete discussion on the usage of the following see the
     Turns a Django template into something that is understood by ``xgettext``.
     It does so by translating the Django translation tags into standard
     ``gettext`` function invocations.
-
-.. data:: LANGUAGE_SESSION_KEY
-
-    Session key under which the active language for the current session is
-    stored.
-
-    .. deprecated:: 3.0
-
-        The language won't be stored in the session in Django 4.0. Use the
-        :setting:`LANGUAGE_COOKIE_NAME` cookie instead.
diff --git a/docs/releases/1.7.txt b/docs/releases/1.7.txt
index 6403ae0b51..2841294067 100644
--- a/docs/releases/1.7.txt
+++ b/docs/releases/1.7.txt
@@ -663,12 +663,11 @@ Internationalization
 
 * The :class:`~django.middleware.locale.LocaleMiddleware` now stores the user's
   selected language with the session key ``_language``. This should only be
-  accessed using the :data:`~django.utils.translation.LANGUAGE_SESSION_KEY`
-  constant. Previously it was stored with the key ``django_language`` and the
-  ``LANGUAGE_SESSION_KEY`` constant did not exist, but keys reserved for Django
-  should start with an underscore. For backwards compatibility ``django_language``
-  is still read from in 1.7. Sessions will be migrated to the new key
-  as they are written.
+  accessed using the ``LANGUAGE_SESSION_KEY`` constant. Previously it was
+  stored with the key ``django_language`` and the ``LANGUAGE_SESSION_KEY``
+  constant did not exist, but keys reserved for Django should start with an
+  underscore. For backwards compatibility ``django_language`` is still read
+  from in 1.7. Sessions will be migrated to the new key as they are written.
 
 * The :ttag:`blocktrans` tag now supports a ``trimmed`` option. This
   option will remove newline characters from the beginning and the end of the
diff --git a/docs/releases/4.0.txt b/docs/releases/4.0.txt
index b5b4d343aa..43e94a790b 100644
--- a/docs/releases/4.0.txt
+++ b/docs/releases/4.0.txt
@@ -254,6 +254,9 @@ to remove usage of these features.
 * ``django.utils.translation.ugettext()``, ``ugettext_lazy()``,
   ``ugettext_noop()``, ``ungettext()``, and ``ungettext_lazy()`` are removed.
 
+* ``django.views.i18n.set_language()`` doesn't set the user language in
+  ``request.session`` (key ``_language``).
+
 See :ref:`deprecated-features-3.1` for details on these changes, including how
 to remove usage of these features.
 
diff --git a/tests/i18n/tests.py b/tests/i18n/tests.py
index 9498103585..315af09e62 100644
--- a/tests/i18n/tests.py
+++ b/tests/i18n/tests.py
@@ -29,11 +29,10 @@ from django.utils.formats import (
 from django.utils.numberformat import format as nformat
 from django.utils.safestring import SafeString, mark_safe
 from django.utils.translation import (
-    LANGUAGE_SESSION_KEY, activate, check_for_language, deactivate,
-    get_language, get_language_bidi, get_language_from_request,
-    get_language_info, gettext, gettext_lazy, ngettext, ngettext_lazy,
-    npgettext, npgettext_lazy, pgettext, round_away_from_one, to_language,
-    to_locale, trans_null, trans_real,
+    activate, check_for_language, deactivate, get_language, get_language_bidi,
+    get_language_from_request, get_language_info, gettext, gettext_lazy,
+    ngettext, ngettext_lazy, npgettext, npgettext_lazy, pgettext,
+    round_away_from_one, to_language, to_locale, trans_null, trans_real,
 )
 from django.utils.translation.reloader import (
     translation_file_changed, watch_for_translation_changes,
@@ -1684,21 +1683,6 @@ class LocaleMiddlewareTests(TestCase):
         response = self.client.get('/en/streaming/')
         self.assertContains(response, "Yes/No")
 
-    @override_settings(
-        MIDDLEWARE=[
-            'django.contrib.sessions.middleware.SessionMiddleware',
-            'django.middleware.locale.LocaleMiddleware',
-            'django.middleware.common.CommonMiddleware',
-        ],
-    )
-    def test_language_not_saved_to_session(self):
-        """
-        The Current language isno' automatically saved to the session on every
-        request (#21473).
-        """
-        self.client.get('/fr/simple/')
-        self.assertNotIn(LANGUAGE_SESSION_KEY, self.client.session)
-
 
 @override_settings(
     USE_I18N=True,
diff --git a/tests/view_tests/tests/test_i18n.py b/tests/view_tests/tests/test_i18n.py
index 84dff20753..091df959fc 100644
--- a/tests/view_tests/tests/test_i18n.py
+++ b/tests/view_tests/tests/test_i18n.py
@@ -4,15 +4,12 @@ from os import path
 
 from django.conf import settings
 from django.test import (
-    RequestFactory, SimpleTestCase, TestCase, ignore_warnings, modify_settings,
+    RequestFactory, SimpleTestCase, TestCase, modify_settings,
     override_settings,
 )
 from django.test.selenium import SeleniumTestCase
 from django.urls import reverse
-from django.utils.deprecation import RemovedInDjango40Warning
-from django.utils.translation import (
-    LANGUAGE_SESSION_KEY, get_language, override,
-)
+from django.utils.translation import get_language, override
 from django.views.i18n import JavaScriptCatalog, get_formats
 
 from ..urls import locale_dir
@@ -37,8 +34,6 @@ class SetLanguageTests(TestCase):
         post_data = {'language': lang_code, 'next': '/'}
         response = self.client.post('/i18n/setlang/', post_data, HTTP_REFERER='/i_should_not_be_used/')
         self.assertRedirects(response, '/')
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
         # The language is set in a cookie.
         language_cookie = self.client.cookies[settings.LANGUAGE_COOKIE_NAME]
         self.assertEqual(language_cookie.value, lang_code)
@@ -59,8 +54,6 @@ class SetLanguageTests(TestCase):
         response = self.client.post('/i18n/setlang/', data=post_data)
         self.assertEqual(response.url, '/')
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
 
     def test_setlang_http_next(self):
         """
@@ -74,14 +67,10 @@ class SetLanguageTests(TestCase):
         response = self.client.post('/i18n/setlang/', data=post_data, secure=True)
         self.assertEqual(response.url, '/')
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
         # Insecure URL in HTTP referer.
         response = self.client.post('/i18n/setlang/', secure=True, HTTP_REFERER=non_https_next_url)
         self.assertEqual(response.url, '/')
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
 
     def test_setlang_redirect_to_referer(self):
         """
@@ -93,8 +82,6 @@ class SetLanguageTests(TestCase):
         response = self.client.post('/i18n/setlang/', post_data, HTTP_REFERER='/i18n/')
         self.assertRedirects(response, '/i18n/', fetch_redirect_response=False)
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
 
     def test_setlang_default_redirect(self):
         """
@@ -106,8 +93,6 @@ class SetLanguageTests(TestCase):
         response = self.client.post('/i18n/setlang/', post_data)
         self.assertRedirects(response, '/')
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
 
     def test_setlang_performs_redirect_for_ajax_if_explicitly_requested(self):
         """
@@ -119,8 +104,6 @@ class SetLanguageTests(TestCase):
         response = self.client.post('/i18n/setlang/', post_data, HTTP_ACCEPT='application/json')
         self.assertRedirects(response, '/')
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
 
     def test_setlang_doesnt_perform_a_redirect_to_referer_for_ajax(self):
         """
@@ -133,8 +116,6 @@ class SetLanguageTests(TestCase):
         response = self.client.post('/i18n/setlang/', post_data, **headers)
         self.assertEqual(response.status_code, 204)
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
 
     def test_setlang_doesnt_perform_a_default_redirect_for_ajax(self):
         """
@@ -146,8 +127,6 @@ class SetLanguageTests(TestCase):
         response = self.client.post('/i18n/setlang/', post_data, HTTP_ACCEPT='application/json')
         self.assertEqual(response.status_code, 204)
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
 
     def test_setlang_unsafe_next_for_ajax(self):
         """
@@ -160,15 +139,6 @@ class SetLanguageTests(TestCase):
         self.assertEqual(response.url, '/')
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
 
-    def test_session_language_deprecation(self):
-        msg = (
-            'The user language will no longer be stored in request.session '
-            'in Django 4.0. Read it from '
-            'request.COOKIES[settings.LANGUAGE_COOKIE_NAME] instead.'
-        )
-        with self.assertRaisesMessage(RemovedInDjango40Warning, msg):
-            self.client.session[LANGUAGE_SESSION_KEY]
-
     def test_setlang_reversal(self):
         self.assertEqual(reverse('set_language'), '/i18n/setlang/')
 
@@ -208,8 +178,6 @@ class SetLanguageTests(TestCase):
         response = self.client.post('/i18n/setlang/', {'language': lang_code}, HTTP_REFERER=encoded_url)
         self.assertRedirects(response, encoded_url, fetch_redirect_response=False)
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, lang_code)
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], lang_code)
 
     @modify_settings(MIDDLEWARE={
         'append': 'django.middleware.locale.LocaleMiddleware',
@@ -220,8 +188,6 @@ class SetLanguageTests(TestCase):
             follow=True, HTTP_REFERER='/en/translated/'
         )
         self.assertEqual(self.client.cookies[settings.LANGUAGE_COOKIE_NAME].value, 'nl')
-        with ignore_warnings(category=RemovedInDjango40Warning):
-            self.assertEqual(self.client.session[LANGUAGE_SESSION_KEY], 'nl')
         self.assertRedirects(response, '/nl/vertaald/')
         # And reverse
         response = self.client.post(