feat: Add LOCALIZE_MENU_ITEMS setting for i18n locale-aware menus (fixes #242)

docs/source/settings_reference.rst

@@ -392,3 +392,43 @@ Use this to specify the 'depth' value of a project's 'section root' pages. For m
 Default value: ``False``
 
 By default, menu items linking to custom URLs are attributed with the 'active' class only if their ``link_url`` value matches the path of the current request _exactly_. Setting this to `True` in your project's settings will enable a smarter approach to active class attribution for custom URLs, where only the 'path' part of the ``link_url`` value is used to determine what active class should be used. The new approach will also attribute the  'ancestor'  class to menu items if the ``link_url`` looks like an ancestor of the current request URL.
+
+
+.. _LOCALIZE_MENU_ITEMS:
+
+``WAGTAILMENUS_LOCALIZE_MENU_ITEMS``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Default value: ``False`` (or ``True`` when ``WAGTAIL_I18N_ENABLED = True``)
+
+When enabled, wagtailmenus will resolve each menu item's ``link_page`` to its
+translation in the currently active locale at render time, so that menu item
+titles and URLs automatically reflect the visitor's language without any
+additional configuration.
+
+If ``WAGTAIL_I18N_ENABLED`` is set to ``True`` in your project's settings,
+this feature is **enabled automatically** — you do not need to set
+``WAGTAILMENUS_LOCALIZE_MENU_ITEMS`` explicitly. You can still opt out by
+setting it to ``False`` even when ``WAGTAIL_I18N_ENABLED`` is ``True``.
+
+.. code-block:: python
+
+    # e.g. settings/base.py
+
+    # Opt in explicitly (not required if WAGTAIL_I18N_ENABLED = True):
+    WAGTAILMENUS_LOCALIZE_MENU_ITEMS = True
+
+    # Opt out even when WAGTAIL_I18N_ENABLED = True:
+    WAGTAILMENUS_LOCALIZE_MENU_ITEMS = False
+
+When active, menu items stored against a default-locale page will be displayed
+using the equivalent page in the active locale (if a translation exists).
+If no translation is found for the active locale, the original page is used as
+a fallback. The localization is applied **at render time only** — the stored
+``link_page`` foreign key on the menu item is never modified.
+
+.. NOTE::
+    Menu items are configured once, against the default-locale page. For this feature to do
+    anything, your pages need translated versions. `wagtail-localize
+    <https://github.com/wagtail/wagtail-localize>`_ is the usual way to produce them, but any
+    Wagtail translation workflow that creates linked ``Locale`` copies will work.

wagtailmenus/conf/defaults.py

@@ -79,6 +79,8 @@
 
 ACTIVE_ANCESTOR_CLASS = 'ancestor'
 
+LOCALIZE_MENU_ITEMS = False
+
 PAGE_FIELD_FOR_MENU_ITEM_TEXT = 'title'
 
 SECTION_ROOT_DEPTH = 3

wagtailmenus/conf/settings.py

@@ -1,10 +1,19 @@
 import sys
 
+from django.conf import settings as django_settings
 from cogwheels import BaseAppSettingsHelper
 
 
 class WagtailmenusSettingsHelper(BaseAppSettingsHelper):
     deprecations = ()
 
+    def __getattr__(self, name):
+        value = super().__getattr__(name)
+        # Auto-detect locale-awareness from Wagtail's own i18n flag when the
+        # wagtailmenus-specific setting has not been explicitly overridden.
+        if name == 'LOCALIZE_MENU_ITEMS' and not self.is_overridden('LOCALIZE_MENU_ITEMS'):
+            return bool(getattr(django_settings, 'WAGTAIL_I18N_ENABLED', False))
+        return value
+
 
 sys.modules[__name__] = WagtailmenusSettingsHelper()

wagtailmenus/models/menus.py

@@ -287,6 +287,21 @@ def pages_for_display(self):
         # using OrderedDict to preserve ordering in Python < 3.6
         return OrderedDict((p.id, p) for p in self.get_pages_for_display())
 
+    @cached_property
+    def localize_page_map(self):
+        """Mapping of stored (default-locale) page IDs to their active-locale
+        page counterparts. Empty dict when LOCALIZE_MENU_ITEMS is disabled."""
+        if not settings.LOCALIZE_MENU_ITEMS:
+            return {}
+        menu_items = getattr(self, '_raw_menu_items', None) or self.get_base_menuitem_queryset()
+        mapping = {}
+        for item in menu_items:
+            if item.link_page:
+                localized = item.link_page.localized
+                if localized and localized.pk != item.link_page.pk:
+                    mapping[item.link_page.pk] = localized
+        return mapping
+
     def get_page_children_dict(self, page_qs=None):
         """
         Returns a dictionary of lists, where the keys are 'path' values for
@@ -963,6 +978,9 @@ def get_top_level_items(self):
         # allow this query result to be reused by get_pages_for_display()
         self._raw_menu_items = menu_items
 
+        pages = self.pages_for_display
+        localize_map = self.localize_page_map
+
         top_level_items = []
         for item in menu_items:
 
@@ -971,10 +989,14 @@ def get_top_level_items(self):
                 top_level_items.append(item)
                 continue
 
+            # Translate the stored (default-locale) FK to the active-locale page
+            # when localization is active, without mutating item.link_page_id.
+            effective_page = localize_map.get(item.link_page_id, item.link_page)
+
             # But, we only want to include links to pages if the page was
             # in the get_pages_for_display() result
             try:
-                item.link_page = self.pages_for_display[item.link_page_id]
+                item.link_page = pages[effective_page.pk]
                 top_level_items.append(item)
             except KeyError:
                 continue
@@ -997,21 +1019,32 @@ def get_pages_for_display(self):
         queryset = Page.objects.none()
 
         for item in (item for item in menu_items if item.link_page):
+            effective_page = self.localize_page_map.get(item.link_page.pk, item.link_page)
+
             if(
                 item.allow_subnav and
-                item.link_page.depth >= settings.SECTION_ROOT_DEPTH
+                effective_page.depth >= settings.SECTION_ROOT_DEPTH
             ):
                 # Add this branch to the overall `queryset`
                 queryset = queryset | Page.objects.filter(
-                    path__startswith=item.link_page.path,
-                    depth__lt=item.link_page.depth + self.max_levels,
+                    path__startswith=effective_page.path,
+                    depth__lt=effective_page.depth + self.max_levels,
                 )
             else:
                 # Add this page only to the overall `queryset`
-                queryset = queryset | Page.objects.filter(id=item.link_page_id)
-
-        # Filter out pages unsutable display
-        queryset = self.get_base_page_queryset() & queryset
+                queryset = queryset | Page.objects.filter(id=effective_page.pk)
+
+        if settings.LOCALIZE_MENU_ITEMS:
+            # `queryset` already contains the localized pages.
+            # Apply the same live/show_in_menus/expired constraints as
+            # get_base_page_queryset() but only against the small set of pages
+            # in `queryset` (scales with menu size, not site size).
+            queryset = self.get_base_page_queryset().filter(
+                id__in=queryset.values('id')
+            )
+        else:
+            # Filter out pages unsuitable for display
+            queryset = self.get_base_page_queryset() & queryset
 
         # Always return 'specific' page instances
         return queryset.specific()