Fixed #23014: Renaming not atomic with unique together

django/db/backends/sqlite3/schema.py

@@ -43,7 +43,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
         else:
             raise ValueError("Cannot quote parameter value %r of type %s" % (value, type(value)))
 
-    def _remake_table(self, model, create_fields=[], delete_fields=[], alter_fields=[], rename_fields=[], override_uniques=None):
+    def _remake_table(self, model, create_fields=[], delete_fields=[], alter_fields=[], override_uniques=None):
         """
         Shortcut to transform a model from old_model into new_model
         """
@@ -52,6 +52,8 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
         # Since mapping might mix column names and default values,
         # its values must be already quoted.
         mapping = dict((f.column, self.quote_name(f.column)) for f in model._meta.local_fields)
+        # This maps field names (not columns) for things like unique_together
+        rename_mapping = {}
         # If any of the new or altered fields is introducing a new PK,
         # remove the old one
         restore_pk_field = None
@@ -77,6 +79,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
             del mapping[old_field.column]
             body[new_field.name] = new_field
             mapping[new_field.column] = self.quote_name(old_field.column)
+            rename_mapping[old_field.name] = new_field.name
         # Remove any deleted fields
         for field in delete_fields:
             del body[field.name]
@@ -92,11 +95,19 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
         # the internal references of some of the provided fields.
         body = copy.deepcopy(body)
 
+        # Work out the new value of unique_together, taking renames into
+        # account
+        if override_uniques is None:
+            override_uniques = [
+                [rename_mapping.get(n, n) for n in unique]
+                for unique in model._meta.unique_together
+            ]
+
         # Construct a new model for the new state
         meta_contents = {
             'app_label': model._meta.app_label,
             'db_table': model._meta.db_table + "__new",
-            'unique_together': model._meta.unique_together if override_uniques is None else override_uniques,
+            'unique_together': override_uniques,
             'apps': apps,
         }
         meta = type("Meta", tuple(), meta_contents)

django/db/migrations/autodetector.py

@@ -791,7 +791,18 @@ class MigrationAutodetector(object):
             old_model_name = self.renamed_models.get((app_label, model_name), model_name)
             old_model_state = self.from_state.models[app_label, old_model_name]
             new_model_state = self.to_state.models[app_label, model_name]
-            if old_model_state.options.get(option_name) != new_model_state.options.get(option_name):
+            # We run the old version through the field renames to account for those
+            if old_model_state.options.get(option_name) is None:
+                old_value = None
+            else:
+                old_value = [
+                    [
+                        self.renamed_fields.get((app_label, model_name, n), n)
+                        for n in unique
+                    ]
+                    for unique in old_model_state.options[option_name]
+                ]
+            if old_value != new_model_state.options.get(option_name):
                 self.add_operation(
                     app_label,
                     operation(

django/db/migrations/operations/fields.py

@@ -162,9 +162,17 @@ class RenameField(Operation):
         self.new_name = new_name
 
     def state_forwards(self, app_label, state):
+        # Rename the field
         state.models[app_label, self.model_name.lower()].fields = [
             (self.new_name if n == self.old_name else n, f) for n, f in state.models[app_label, self.model_name.lower()].fields
         ]
+        # Fix unique_together to refer to the new field
+        options = state.models[app_label, self.model_name.lower()].options
+        if "unique_together" in options:
+            options['unique_together'] = [
+                [self.new_name if n == self.old_name else n for n in unique]
+                for unique in options['unique_together']
+            ]
 
     def database_forwards(self, app_label, schema_editor, from_state, to_state):
         from_model = from_state.render().get_model(app_label, self.model_name)

tests/migrations/test_operations.py

@@ -46,7 +46,7 @@ class OperationTestBase(MigrationTestBase):
         operation.state_forwards(app_label, new_state)
         return project_state, new_state
 
-    def set_up_test_model(self, app_label, second_model=False, third_model=False, related_model=False, mti_model=False, proxy_model=False):
+    def set_up_test_model(self, app_label, second_model=False, third_model=False, related_model=False, mti_model=False, proxy_model=False, unique_together=False):
         """
         Creates a test model state and database table.
         """
@@ -85,6 +85,7 @@ class OperationTestBase(MigrationTestBase):
             ],
             options={
                 "swappable": "TEST_SWAP_MODEL",
+                "unique_together": [["pink", "weight"]] if unique_together else [],
             },
         )]
         if second_model:
@@ -862,7 +863,7 @@ class OperationTests(OperationTestBase):
         """
         Tests the RenameField operation.
         """
-        project_state = self.set_up_test_model("test_rnfl")
+        project_state = self.set_up_test_model("test_rnfl", unique_together=True)
         # Test the state alteration
         operation = migrations.RenameField("Pony", "pink", "blue")
         self.assertEqual(operation.describe(), "Rename field pink on Pony to blue")
@@ -870,6 +871,9 @@ class OperationTests(OperationTestBase):
         operation.state_forwards("test_rnfl", new_state)
         self.assertIn("blue", [n for n, f in new_state.models["test_rnfl", "pony"].fields])
         self.assertNotIn("pink", [n for n, f in new_state.models["test_rnfl", "pony"].fields])
+        # Make sure the unique_together has the renamed column too
+        self.assertIn("blue", new_state.models["test_rnfl", "pony"].options['unique_together'][0])
+        self.assertNotIn("pink", new_state.models["test_rnfl", "pony"].options['unique_together'][0])
         # Test the database alteration
         self.assertColumnExists("test_rnfl_pony", "pink")
         self.assertColumnNotExists("test_rnfl_pony", "blue")
@@ -877,6 +881,13 @@ class OperationTests(OperationTestBase):
             operation.database_forwards("test_rnfl", editor, project_state, new_state)
         self.assertColumnExists("test_rnfl_pony", "blue")
         self.assertColumnNotExists("test_rnfl_pony", "pink")
+        # Ensure the unique constraint has been ported over
+        with connection.cursor() as cursor:
+            cursor.execute("INSERT INTO test_rnfl_pony (blue, weight) VALUES (1, 1)")
+            with self.assertRaises(IntegrityError):
+                with atomic():
+                    cursor.execute("INSERT INTO test_rnfl_pony (blue, weight) VALUES (1, 1)")
+            cursor.execute("DELETE FROM test_rnfl_pony")
         # And test reversal
         with connection.schema_editor() as editor:
             operation.database_backwards("test_rnfl", editor, new_state, project_state)