Fixed #35393 -- Added excluded pk as a hidden field to the inline admin.

django/contrib/admin/helpers.py

@@ -509,6 +509,11 @@ def needs_explicit_pk_field(self):
             # Auto fields are editable, so check for auto or non-editable pk.
             self.form._meta.model._meta.auto_field
             or not self.form._meta.model._meta.pk.editable
+            # The pk can be editable, but excluded from the inline.
+            or (
+                self.form._meta.exclude
+                and self.form._meta.model._meta.pk.name in self.form._meta.exclude
+            )
             or
             # Also search any parents for an auto field. (The pk info is
             # propagated to child models so that does not need to be checked

tests/admin_inlines/admin.py

@@ -57,6 +57,8 @@
     Teacher,
     Title,
     TitleCollection,
+    UUIDChild,
+    UUIDParent,
 )
 
 site = admin.AdminSite(name="admin")
@@ -471,6 +473,16 @@ class ShowInlineChildInline(admin.StackedInline):
     model = ShowInlineChild
 
 
+class UUIDChildInline(admin.StackedInline):
+    model = UUIDChild
+    exclude = ("id",)
+
+
+class UUIDParentModelAdmin(admin.ModelAdmin):
+    model = UUIDParent
+    inlines = [UUIDChildInline]
+
+
 class ShowInlineParentAdmin(admin.ModelAdmin):
     def get_inlines(self, request, obj):
         if obj is not None and obj.show_inlines:
@@ -513,6 +525,7 @@ def get_inlines(self, request, obj):
 site.register(CourseProxy1, ClassAdminTabularVertical)
 site.register(CourseProxy2, ClassAdminTabularHorizontal)
 site.register(ShowInlineParent, ShowInlineParentAdmin)
+site.register(UUIDParent, UUIDParentModelAdmin)
 # Used to test hidden fields in tabular and stacked inlines.
 site2 = admin.AdminSite(name="tabular_inline_hidden_field_admin")
 site2.register(SomeParentModel, inlines=[ChildHiddenFieldTabularInline])

tests/admin_inlines/models.py

@@ -3,6 +3,7 @@
 """
 
 import random
+import uuid
 
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
@@ -399,3 +400,13 @@ class BothVerboseNameProfile(Profile):
     class Meta:
         verbose_name = "Model with both - name"
         verbose_name_plural = "Model with both - plural name"
+
+
+class UUIDParent(models.Model):
+    pass
+
+
+class UUIDChild(models.Model):
+    id = models.UUIDField(default=uuid.uuid4, primary_key=True)
+    title = models.CharField(max_length=128)
+    parent = models.ForeignKey(UUIDParent, on_delete=models.CASCADE)

tests/admin_inlines/tests.py

@@ -44,6 +44,8 @@
     SomeChildModel,
     SomeParentModel,
     Teacher,
+    UUIDChild,
+    UUIDParent,
     VerboseNamePluralProfile,
     VerboseNameProfile,
 )
@@ -115,6 +117,19 @@ def test_readonly_stacked_inline_label(self):
         )
         self.assertContains(response, "<label>Inner readonly label:</label>")
 
+    def test_excluded_id_for_inlines_uses_hidden_field(self):
+        parent = UUIDParent.objects.create()
+        child = UUIDChild.objects.create(title="foo", parent=parent)
+        response = self.client.get(
+            reverse("admin:admin_inlines_uuidparent_change", args=(parent.id,))
+        )
+        self.assertContains(
+            response,
+            f'<input type="hidden" name="uuidchild_set-0-id" value="{child.id}" '
+            'id="id_uuidchild_set-0-id">',
+            html=True,
+        )
+
     def test_many_to_many_inlines(self):
         "Autogenerated many-to-many inlines are displayed correctly (#13407)"
         response = self.client.get(reverse("admin:admin_inlines_author_add"))