Prevent errors on get_url_parts when a non-content-language locale is active (#6521)

Fixes #6510 and #6511

Catch the LookupError from get_supported_content_language_variant so that if the active language is not one that is recognised as a content language, the URL prefix will be left unchanged from the page's reported locale.

Additionally, skip the `translation.override` when WAGTAIL_I18N_ENABLED is false; this accounts for the fact that existing sites may have used alternative / custom i18n implementations involving i18n_patterns, and on these sites we can't rely on the page's locale field to be meaningful. That way, we restore the pre-2.11 behaviour: if the existing i18n code was using some kind of wrapper around the get_url_parts call, then that will work again; and if not, the URL will reflect the current active locale, which is no worse than before.

CHANGELOG.txt

@@ -12,6 +12,7 @@ Changelog
 
  * Fix: Ensure that cached `wagtail_site_root_paths` structures from older Wagtail versions are invalidated (Sævar Öfjörð Magnússon)
  * Fix: Avoid circular import between wagtail.admin.auth and custom user models (Matt Westcott)
+ * Fix: Prevent error on resolving page URLs when a locale outside of `WAGTAIL_CONTENT_LANGUAGES` is active (Matt Westcott)
 
 
 2.11 LTS (02.11.2020)

docs/releases/2.11.1.rst

@@ -15,3 +15,4 @@ Bug fixes
 
  * Ensure that cached ``wagtail_site_root_paths`` structures from older Wagtail versions are invalidated (Sævar Öfjörð Magnússon)
  * Avoid circular import between wagtail.admin.auth and custom user models (Matt Westcott)
+ * Prevent error on resolving page URLs when a locale outside of ``WAGTAIL_CONTENT_LANGUAGES`` is active (Matt Westcott)

wagtail/admin/tests/api/test_pages.py

@@ -2,6 +2,7 @@ import collections
 import datetime
 import json
 
+from django.contrib.auth import get_user_model
 from django.urls import reverse
 from django.utils import timezone
 
@@ -9,6 +10,7 @@ from wagtail.api.v2.tests.test_pages import TestPageDetail, TestPageListing
 from wagtail.core.models import Locale, Page
 from wagtail.tests.demosite import models
 from wagtail.tests.testapp.models import SimplePage, StreamPage
+from wagtail.users.models import UserProfile
 
 from .utils import AdminAPITestCase
 
@@ -101,6 +103,20 @@ class TestAdminPageListing(AdminAPITestCase, TestPageListing):
         content = json.loads(response.content.decode('UTF-8'))
         self.assertEqual(content['meta']['total_count'], new_total_count)
 
+    def test_get_in_non_content_language(self):
+        # set logged-in user's admin UI language to Swedish
+        user = get_user_model().objects.get(email='test@email.com')
+        UserProfile.objects.update_or_create(user=user, defaults={'preferred_language': 'se'})
+
+        response = self.get_response()
+
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response['Content-type'], 'application/json')
+
+        # Will crash if the JSON is invalid
+        content = json.loads(response.content.decode('UTF-8'))
+        self.assertIn('meta', content)
+
     # FIELDS
 
     # Not applicable to the admin API

wagtail/core/models.py

@@ -1585,16 +1585,28 @@ class Page(AbstractPage, index.Indexed, ClusterableModel, metaclass=PageBase):
             else:
                 site_id, root_path, root_url, language_code = possible_sites[0]
 
-        # If the active language code is a variant of the page's language, then
-        # use that instead
-        # This is used when LANGUAGES contain more languages than WAGTAIL_CONTENT_LANGUAGES
-        if get_supported_content_language_variant(translation.get_language()) == language_code:
-            language_code = translation.get_language()
+        use_wagtail_i18n = getattr(settings, 'WAGTAIL_I18N_ENABLED', False)
+
+        if use_wagtail_i18n:
+            # If the active language code is a variant of the page's language, then
+            # use that instead
+            # This is used when LANGUAGES contain more languages than WAGTAIL_CONTENT_LANGUAGES
+            try:
+                if get_supported_content_language_variant(translation.get_language()) == language_code:
+                    language_code = translation.get_language()
+            except LookupError:
+                # active language code is not a recognised content language, so leave
+                # page's language code unchanged
+                pass
 
         # The page may not be routable because wagtail_serve is not registered
         # This may be the case if Wagtail is used headless
         try:
-            with translation.override(language_code):
+            if use_wagtail_i18n:
+                with translation.override(language_code):
+                    page_path = reverse(
+                        'wagtail_serve', args=(self.url_path[len(root_path):],))
+            else:
                 page_path = reverse(
                     'wagtail_serve', args=(self.url_path[len(root_path):],))
         except NoReverseMatch:

wagtail/core/tests/test_page_model.py

@@ -499,6 +499,12 @@ class TestRoutingWithI18N(TestRouting):
         with translation.override("en-us"):
             self.test_urls()
 
+    def test_urls_with_language_not_in_wagtail_content_languages(self):
+        # If the active locale doesn't map to anything in WAGTAIL_CONTENT_LANGUAGES,
+        # URL prefixes should remain the same as the page's reported locale
+        with translation.override("se"):
+            self.test_urls()
+
     def test_urls_with_different_language_tree(self):
         default_site = Site.objects.get(is_default_site=True)
         homepage = Page.objects.get(url_path='/home/')