[1.7.x] Fixed #23950 -- Prevented calling deconstruct on classes in MigrationWriter.

Backport of dee4d23f7e703aec2d1244e4facbf7f4c88deed5 from master

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/migrations/test_writer.py b/tests/migrations/test_writer.py
index cb9ed5d0d5..dc551acc6b 100644
--- a/tests/migrations/test_writer.py
+++ b/tests/migrations/test_writer.py
@@ -340,3 +340,14 @@ class WriterTests(TestCase):
         fixed_offset_datetime = datetime.datetime(2014, 1, 1, 1, 1, tzinfo=FixedOffset(180))
         self.assertEqual(MigrationWriter.serialize_datetime(fixed_offset_datetime),
                          "datetime.datetime(2013, 12, 31, 22, 1, tzinfo=utc)")
+
+    def test_deconstruct_class_arguments(self):
+        # Yes, it doesn't make sense to use a class as a default for a
+        # CharField. It does make sense for custom fields though, for example
+        # an enumfield that takes the enum class as an argument.
+        class DeconstructableInstances(object):
+            def deconstruct(self):
+                return ('DeconstructableInstances', [], {})
+
+        string = MigrationWriter.serialize(models.CharField(default=DeconstructableInstances))[0]
+        self.assertEqual(string, "models.CharField(default=migrations.test_writer.DeconstructableInstances)")