id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
32886	Translation: clash between language cookie and i18n_patterns URLs	Seb G	Charlie Overton	"= Summary

When using `i18n_patterns`, language cookie is disregarded, even in non-`i18n_patterns` views.

= Description

Given the following project `urls.py` file:


{{{
#!python
from django.conf.urls.i18n import i18n_patterns
from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path(""admin/"", admin.site.urls),
]

urlpatterns += i18n_patterns(
    path(""app/"", include(""app.urls"", namespace=""app"")),
    prefix_default_language=False,
)
}}}

Browsing to `/admin/` with a valid `django_language` cookie whose value is `fr` still returns an english-translated page.

This behavior seems to emerge from the `LocaleMiddleware.process_request` method:

{{{
#!python
def process_request(self, request):
    urlconf = getattr(request, 'urlconf', settings.ROOT_URLCONF)
    
    # This returns (True, False) because i18n_patterns are indeed used (albeit not on the requested route)
    i18n_patterns_used, prefixed_default_language = is_language_prefix_patterns_used(urlconf)
    
    # This returns ""fr"" as expected from the django_language cookie
    language = translation.get_language_from_request(request, check_path=i18n_patterns_used)
    
    # This returns None since, indeed, this route does not use i18n_patterns
    language_from_path = translation.get_language_from_path(request.path_info)

    # This test passes (somewhat unfortunately)
    if not language_from_path and i18n_patterns_used and not prefixed_default_language:
        # This gets executed and reverts language to default language (en)
        language = settings.LANGUAGE_CODE

    # ""en"" gets activated instead of ""fr""
    translation.activate(language)
    request.LANGUAGE_CODE = translation.get_language()
}}}

= Steps to reproduce

Using the provided test project

1. `python manage.py migrate`
2. `python manage.py createsuperuser`
3. `python manage.py runserver`
4. Browse to `/admin/`
5. Login as superuser
6. Edit your own user to set its language to ""fr"". Verify that you now have a `django_language=fr` cookie
7. Browse to any admin page => not translated to ""fr""

= Expected behavior

Cookie language should be respected on routes that do '''not''' use i18n_patterns. It is ok though that path language overrides cookie language on routes that '''do''' use i18n_patterns."	Bug	assigned	Internationalization	3.2	Normal				Accepted	0	0	0	0	0	0