Clean up post-middleware language activation

See #161

bugsink/middleware.py

@@ -150,17 +150,17 @@ def language_from_accept_language(request):
     return settings.LANGUAGE_CODE
 
 
+def get_chosen_language(request_user, request):
+    if request_user.is_authenticated and request_user.language != "auto":
+        return get_supported_language_variant(request_user.language, strict=False)
+    return language_from_accept_language(request)
+
+
 class UserLanguageMiddleware:
     def __init__(self, get_response):
         self.get_response = get_response
 
     def __call__(self, request):
-        if request.user.is_authenticated and request.user.language != "auto":
-            normalized_explicit_lang = get_supported_language_variant(request.user.language, strict=False)
-            translation.activate(normalized_explicit_lang)
-        else:
-            auto_lang = language_from_accept_language(request)
-            translation.activate(auto_lang)
-
+        translation.activate(get_chosen_language(request.user, request))
         response = self.get_response(request)
         return response

users/views.py

@@ -8,9 +8,11 @@ from django.utils import timezone
 from django.contrib import messages
 from django.contrib.auth.decorators import login_required, user_passes_test
 from django.utils.translation import gettext as _
+from django.utils import translation
 
 from bugsink.app_settings import get_settings, CB_ANYBODY
 from bugsink.decorators import atomic_for_request_method
+from bugsink.middleware import get_chosen_language
 
 from .forms import (
     UserCreationForm, ResendConfirmationForm, RequestPasswordResetForm, SetPasswordForm, PreferencesForm, UserEditForm)
@@ -226,9 +228,11 @@ def preferences(request):
         form = PreferencesForm(request.POST, instance=user)
 
         if form.is_valid():
-            form.save()
-            from django.utils import translation
-            translation.activate(user.language if user.language != 'auto' else translation.get_language())
+            user = form.save()
+
+            # activate the selected language immediately for the Success message; we've already passed the middleware
+            # stage (which looked at the pre-change language), so we need to do this ourselves with the fresh value.
+            translation.activate(get_chosen_language(user, request))
 
             messages.success(request, _("Updated preferences"))
             return redirect('preferences')