Refs #26001 -- Handled relationship exact lookups in ModelAdmin.search_fields.

tests/admin_changelist/admin.py

@@ -56,6 +56,7 @@ class ChildAdmin(admin.ModelAdmin):
 
 class GrandChildAdmin(admin.ModelAdmin):
     list_display = ["name", "parent__name", "parent__parent__name"]
+    search_fields = ["parent__name__exact", "parent__age__exact"]
 
 
 site.register(GrandChild, GrandChildAdmin)

tests/admin_changelist/tests.py

@@ -879,6 +879,28 @@ class ChangeListTests(TestCase):
                     cl = model_admin.get_changelist_instance(request)
                 self.assertCountEqual(cl.queryset, expected_result)
 
+    def test_search_with_exact_lookup_relationship_field(self):
+        child = Child.objects.create(name="I am a child", age=11)
+        grandchild = GrandChild.objects.create(name="I am a grandchild", parent=child)
+        model_admin = GrandChildAdmin(GrandChild, custom_site)
+
+        request = self.factory.get("/", data={SEARCH_VAR: "'I am a child'"})
+        request.user = self.superuser
+        cl = model_admin.get_changelist_instance(request)
+        self.assertCountEqual(cl.queryset, [grandchild])
+        for search_term, expected_result in [
+            ("11", [grandchild]),
+            ("'I am a child'", [grandchild]),
+            ("1", []),
+            ("A", []),
+            ("random", []),
+        ]:
+            request = self.factory.get("/", data={SEARCH_VAR: search_term})
+            request.user = self.superuser
+            with self.subTest(search_term=search_term):
+                cl = model_admin.get_changelist_instance(request)
+                self.assertCountEqual(cl.queryset, expected_result)
+
     def test_no_distinct_for_m2m_in_list_filter_without_params(self):
         """
         If a ManyToManyField is in list_filter but isn't in any lookup params,