[5.1.x] Fixed #35876 -- Displayed non-ASCII fieldset names when rendering ModelAdmin.fieldsets.

Thank you to Namhong Kim for the report, and to Mariusz Felisiak and Marijke Luttekes for the review.

Regression in 01ed59f753139afb514170ee7f7384c155ecbc2d.

Backport of 2c029c718f45341cdd43ee094c24488743c633e6 from main.

django/contrib/admin/templates/admin/includes/fieldset.html

@@ -1,8 +1,7 @@
-{% with name=fieldset.name|default:""|slugify %}
-<fieldset class="module aligned {{ fieldset.classes }}"{% if name %} aria-labelledby="{{ prefix }}-{{ id_prefix}}-{{ name }}-{{ id_suffix }}-heading"{% endif %}>
-    {% if name %}
+<fieldset class="module aligned {{ fieldset.classes }}"{% if fieldset.name %} aria-labelledby="{{ prefix }}-{{ id_prefix}}-{{ id_suffix }}-heading"{% endif %}>
+    {% if fieldset.name %}
         {% if fieldset.is_collapsible %}<details><summary>{% endif %}
-        <h{{ heading_level|default:2 }} id="{{ prefix }}-{{ id_prefix}}-{{ name }}-{{ id_suffix }}-heading" class="fieldset-heading">{{ fieldset.name }}</h{{ heading_level|default:2 }}>
+        <h{{ heading_level|default:2 }} id="{{ prefix }}-{{ id_prefix}}-{{ id_suffix }}-heading" class="fieldset-heading">{{ fieldset.name }}</h{{ heading_level|default:2 }}>
         {% if fieldset.is_collapsible %}</summary>{% endif %}
     {% endif %}
     {% if fieldset.description %}
@@ -36,6 +35,5 @@
             {% if not line.fields|length == 1 %}</div>{% endif %}
         </div>
     {% endfor %}
-    {% if name and fieldset.is_collapsible %}</details>{% endif %}
+    {% if fieldset.name and fieldset.is_collapsible %}</details>{% endif %}
 </fieldset>
-{% endwith %}

docs/releases/5.1.3.txt

@@ -17,3 +17,6 @@ Bugfixes
 
 * Fixed a regression in Django 5.1 that prevented the use of DB-IP databases
   with :class:`~django.contrib.gis.geoip2.GeoIP2` (:ticket:`35841`).
+
+* Fixed a regression in Django 5.1 where non-ASCII fieldset names were not
+  displayed when rendering admin fieldsets (:ticket:`35876`).

tests/admin_inlines/tests.py

@@ -1785,7 +1785,7 @@ class TestInlineWithFieldsets(TestDataMixin, TestCase):
         # The second and third have the same "Advanced options" name, but the
         # second one has the "collapse" class.
         for x, classes in ((1, ""), (2, "collapse")):
-            heading_id = f"fieldset-0-advanced-options-{x}-heading"
+            heading_id = f"fieldset-0-{x}-heading"
             with self.subTest(heading_id=heading_id):
                 self.assertContains(
                     response,
@@ -1830,7 +1830,7 @@ class TestInlineWithFieldsets(TestDataMixin, TestCase):
                 # Every fieldset defined for an inline's form.
                 for z, fieldset in enumerate(inline_admin_form):
                     if fieldset.name:
-                        heading_id = f"{prefix}-{y}-details-{z}-heading"
+                        heading_id = f"{prefix}-{y}-{z}-heading"
                         self.assertContains(
                             response,
                             f'<fieldset class="module aligned {fieldset.classes}" '

tests/admin_views/admin.py

@@ -237,6 +237,7 @@ class ArticleAdmin(ArticleAdminWithExtraUrl):
             "Some other fields",
             {"classes": ("wide",), "fields": ("date", "section", "sub_section")},
         ),
+        ("이름", {"fields": ("another_section",)}),
     )
 
     # These orderings aren't particularly useful but show that expressions can

tests/admin_views/tests.py

@@ -2508,6 +2508,19 @@ class AdminViewPermissionsTest(TestCase):
         self.assertContains(
             response, '<input type="submit" value="Save and view" name="_continue">'
         )
+        self.assertContains(
+            response,
+            '<h2 id="fieldset-0-0-heading" class="fieldset-heading">Some fields</h2>',
+        )
+        self.assertContains(
+            response,
+            '<h2 id="fieldset-0-1-heading" class="fieldset-heading">'
+            "Some other fields</h2>",
+        )
+        self.assertContains(
+            response,
+            '<h2 id="fieldset-0-2-heading" class="fieldset-heading">이름</h2>',
+        )
         post = self.client.post(
             reverse("admin:admin_views_article_add"), add_dict, follow=False
         )