Fixed #36921 -- Fixed KeyError in inline form for model not registered with admin.

Regression in b1ffa9a9d78b0c2c5ad6ed5a1d84e380d5cfd010.

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/admin_views/tests.py b/tests/admin_views/tests.py
index 7f35d7c2f4..fa9d9a2dc6 100644
--- a/tests/admin_views/tests.py
+++ b/tests/admin_views/tests.py
@@ -589,6 +589,31 @@ class AdminViewBasicTest(AdminViewBasicTestCase):
         self.assertIn("admin_views.nonexistent", str(messages[0]))
         self.assertIn("could not be found", str(messages[0]))
 
+    def test_popup_add_POST_with_unregistered_source_model(self):
+        """
+        Popup add where source_model is a valid Django model but is not
+        registered in the admin site (e.g. a model only used as an inline)
+        should succeed without raising a KeyError.
+        """
+        post_data = {
+            IS_POPUP_VAR: "1",
+            # Chapter exists as a model but is not registered in site (only
+            # in site6), simulating a model used only as an inline.
+            SOURCE_MODEL_VAR: "admin_views.chapter",
+            "title": "Test Article",
+            "content": "some content",
+            "date_0": "2010-09-10",
+            "date_1": "14:55:39",
+        }
+        response = self.client.post(reverse("admin:admin_views_article_add"), post_data)
+        self.assertEqual(response.status_code, 200)
+        self.assertContains(response, "data-popup-response")
+        # No error messages - unregistered model is silently skipped.
+        messages = list(response.wsgi_request._messages)
+        self.assertEqual(len(messages), 0)
+        # No optgroup in the response.
+        self.assertNotContains(response, ""optgroup"")
+
     def test_basic_edit_POST(self):
         """
         A smoke test to ensure POST on edit_view works.