Fixed 2259 -- Made manually defined PKs readonly in admin inlines.

Jkhall81 · Jkhall81 · commit 893d26518982 · 2025-07-29T11:24:30.000-07:00
diff --git a/django/contrib/admin/options.py b/django/contrib/admin/options.py
@@ -414,6 +414,20 @@ def get_ordering(self, request):
         """
         return self.ordering or ()  # otherwise we might try to *None, which is bad ;)
 
+    def _get_readonly_manual_pk_fields(self, obj):
+        """
+        Returns a list containing the primary key field name if:
+        - we're editing an existing object,
+        - the PK was manually defined (not auto-created),
+        - and it's not already in self.readonly_fields.
+        """
+        if not obj:
+            return []
+        pk = self.model._meta.pk
+        if pk.editable and not pk.auto_created and pk.name not in self.readonly_fields:
+            return [pk.name]
+        return []
+
     def get_readonly_fields(self, request, obj=None):
         """
         Hook for specifying custom readonly fields.
diff --git a/django/contrib/admin/static/admin/css/base.css b/django/contrib/admin/static/admin/css/base.css
@@ -109,10 +109,6 @@ body {
     background: var(--body-bg);
 }
 
-label {
-    font-size: 1rem;
-}
-
 /* LINKS */
 
 a:link, a:visited {
diff --git a/tests/admin_inlines/tests.py b/tests/admin_inlines/tests.py
@@ -19,6 +19,7 @@
     Child,
     ChildModel1,
     ChildModel2,
+    EditablePKBook,
     ExtraTerrestrial,
     Fashionista,
     FootNote,
@@ -708,6 +709,21 @@ def test_inline_editable_pk(self):
             count=1,
         )
 
+    def test_inline_manual_pk_is_readonly_when_editing(self):
+        author = Author.objects.create(name="Jane Austen")
+        EditablePKBook.objects.create(
+            author=author, manual_pk=101, title="Pride and Prejudice"
+        )
+
+        response = self.client.get(
+            reverse("admin:admin_inlines_author_change", args=[author.pk])
+        )
+
+        self.assertContains(
+            response, 'name="editablepkbook_set-0-manual_pk"', html=False
+        )
+        self.assertContains(response, "readonly", html=False)
+
     def test_stacked_inline_edit_form_contains_has_original_class(self):
         holder = Holder.objects.create(dummy=1)
         holder.inner_set.create(dummy=1)

Original file line number	Diff line number	Diff line change
`@@ -109,10 +109,6 @@ body {`
`109`	`109`	`background: var(--body-bg);`
`110`	`110`	`}`
`111`	`111`
`112`		`-label {`
`113`		`- font-size: 1rem;`
`114`		`-}`
`115`		`-`
`116`	`112`	`/* LINKS */`
`117`	`113`
`118`	`114`	`a:link, a:visited {`