Fixed #23288: deconstruct() ignoring related_name

Author: andrewgodwin

django/db/models/fields/related.py

@@ -1383,6 +1383,14 @@ def deconstruct(self):
         name, path, args, kwargs = super(ForeignObject, self).deconstruct()
         kwargs['from_fields'] = self.from_fields
         kwargs['to_fields'] = self.to_fields
+        if self.rel.related_name is not None:
+            kwargs['related_name'] = self.rel.related_name
+        if self.rel.related_query_name is not None:
+            kwargs['related_query_name'] = self.rel.related_query_name
+        if self.rel.on_delete != CASCADE:
+            kwargs['on_delete'] = self.rel.on_delete
+        if self.rel.parent_link:
+            kwargs['parent_link'] = self.rel.parent_link
         # Work out string form of "to"
         if isinstance(self.rel.to, six.string_types):
             kwargs['to'] = self.rel.to
@@ -1670,8 +1678,6 @@ def deconstruct(self):
             kwargs['db_index'] = False
         if self.db_constraint is not True:
             kwargs['db_constraint'] = self.db_constraint
-        if self.rel.on_delete is not CASCADE:
-            kwargs['on_delete'] = self.rel.on_delete
         # Rel needs more work.
         to_meta = getattr(self.rel.to, "_meta", None)
         if self.rel.field_name and (not to_meta or (to_meta.pk and self.rel.field_name != to_meta.pk.name)):
@@ -2142,6 +2148,10 @@ def deconstruct(self):
             kwargs['db_table'] = self.db_table
         if self.rel.db_constraint is not True:
             kwargs['db_constraint'] = self.rel.db_constraint
+        if self.rel.related_name is not None:
+            kwargs['related_name'] = self.rel.related_name
+        if self.rel.related_query_name is not None:
+            kwargs['related_query_name'] = self.rel.related_query_name
         # Rel needs more work.
         if isinstance(self.rel.to, six.string_types):
             kwargs['to'] = self.rel.to

tests/field_deconstruction/tests.py

@@ -203,6 +203,12 @@ def test_foreign_key(self):
         self.assertEqual(path, "django.db.models.ForeignKey")
         self.assertEqual(args, [])
         self.assertEqual(kwargs, {"to": "auth.Permission", "to_field": "foobar"})
+        # Test related_name preservation
+        field = models.ForeignKey("auth.Permission", related_name="foobar")
+        name, path, args, kwargs = field.deconstruct()
+        self.assertEqual(path, "django.db.models.ForeignKey")
+        self.assertEqual(args, [])
+        self.assertEqual(kwargs, {"to": "auth.Permission", "related_name": "foobar"})
 
     @override_settings(AUTH_USER_MODEL="auth.Permission")
     def test_foreign_key_swapped(self):
@@ -277,6 +283,12 @@ def test_many_to_many_field(self):
         self.assertEqual(path, "django.db.models.ManyToManyField")
         self.assertEqual(args, [])
         self.assertEqual(kwargs, {"to": "auth.Permission", "db_table": "custom_table"})
+        # Test related_name
+        field = models.ManyToManyField("auth.Permission", related_name="custom_table")
+        name, path, args, kwargs = field.deconstruct()
+        self.assertEqual(path, "django.db.models.ManyToManyField")
+        self.assertEqual(args, [])
+        self.assertEqual(kwargs, {"to": "auth.Permission", "related_name": "custom_table"})
 
     @override_settings(AUTH_USER_MODEL="auth.Permission")
     def test_many_to_many_field_swapped(self):