[3.0.x] Refs #27914 -- Fixed serialization of nested enum.Enum classes in migrations.

Backport of 6452112640081ac8838147a8ba192c45879203d8 from master

2 files changed, 12 insertions, 1 deletions

diff --git a/django/db/migrations/serializer.py b/django/db/migrations/serializer.py
index 8aa6a04935..7d226955d5 100644
--- a/django/db/migrations/serializer.py
+++ b/django/db/migrations/serializer.py
@@ -121,7 +121,7 @@ class EnumSerializer(BaseSerializer):
         enum_class = self.value.__class__
         module = enum_class.__module__
         return (
-            '%s.%s[%r]' % (module, enum_class.__name__, self.value.name),
+            '%s.%s[%r]' % (module, enum_class.__qualname__, self.value.name),
             {'import %s' % module},
         )
 
diff --git a/tests/migrations/test_writer.py b/tests/migrations/test_writer.py
index 7caca12b7d..ca924f35ec 100644
--- a/tests/migrations/test_writer.py
+++ b/tests/migrations/test_writer.py
@@ -184,6 +184,9 @@ class WriterTests(SimpleTestCase):
     """
     Tests the migration writer (makes migration files from Migration instances)
     """
+    class NestedEnum(enum.IntEnum):
+        A = 1
+        B = 2
 
     def safe_exec(self, string, value=None):
         d = {}
@@ -289,6 +292,14 @@ class WriterTests(SimpleTestCase):
             IntEnum.B,
             ("migrations.test_writer.IntEnum['B']", {'import migrations.test_writer'})
         )
+        self.assertSerializedResultEqual(
+            self.NestedEnum.A,
+            (
+                "migrations.test_writer.WriterTests.NestedEnum['A']",
+                {'import migrations.test_writer'},
+            ),
+        )
+        self.assertSerializedEqual(self.NestedEnum.A)
 
         field = models.CharField(default=TextEnum.B, choices=[(m.value, m) for m in TextEnum])
         string = MigrationWriter.serialize(field)[0]