Added handling for lazily evaluated page_description, fixes #8523 (#8527)

CHANGELOG.txt

@@ -38,7 +38,7 @@ Changelog
  * Split up linting / formatting tasks in Makefile into client and server components (Hitansh Shah)
  * Add support for embedding Instagram reels (Luis Nell)
  * Use Django’s JavaScript catalog feature to manage translatable strings in JavaScript (Karl Hobley)
- * Add a `page_description` to the Page model, to provide help text for a given page type (Kalob Taulien, Thibaud Colas, Matt Westcott)
+ * Add a `page_description` to the Page model, to provide help text for a given page type (Kalob Taulien, Thibaud Colas, Matt Westcott, Stefan Hammer)
  * Add `trimmed` attribute to all blocktrans tags, so spacing is more reliable in translated strings (Harris Lapiroff)
  * Add documentation that describes how to use `ModelAdmin` to manage `Tag`s (Abdulmajeed Isa)
  * Rename the setting `BASE_URL` (undocumented) to `WAGTAILADMIN_BASE_URL` and add to documentation, `BASE_URL` will be removed in a future release (Sandil Ranasinghe)

wagtail/admin/tests/pages/test_create_page.py

@@ -69,6 +69,7 @@ class TestPageCreation(TestCase, WagtailTestUtils):
         self.assertEqual(response.status_code, 200)
 
         self.assertContains(response, "Business child")
+        self.assertContains(response, "A lazy business child page description")
         # List should not contain page types not in the subpage_types list
         self.assertNotContains(response, "Simple page")
 

wagtail/models/__init__.py

@@ -1509,6 +1509,9 @@ class Page(AbstractPage, index.Indexed, ClusterableModel, metaclass=PageBase):
         # make sure that page_description is actually a string rather than a model field
         if isinstance(description, str):
             return description
+        elif getattr(description, "_delegate_text", None):
+            # description is a lazy object (e.g. the result of gettext_lazy())
+            return str(description)
         else:
             return ""
 

wagtail/test/testapp/models.py

@@ -11,6 +11,7 @@ from django.core.paginator import EmptyPage, PageNotAnInteger, Paginator
 from django.db import models
 from django.shortcuts import redirect
 from django.template.response import TemplateResponse
+from django.utils.functional import lazystr
 from modelcluster.contrib.taggit import ClusterTaggableManager
 from modelcluster.fields import ParentalKey, ParentalManyToManyField
 from modelcluster.models import ClusterableModel
@@ -976,6 +977,7 @@ class BusinessChild(Page):
 
     subpage_types = []
     parent_page_types = ["tests.BusinessIndex", BusinessSubIndex]
+    page_description = lazystr("A lazy business child page description")
 
 
 class BusinessNowherePage(Page):