Made Operation.references_model/references_field require app_label.

This will allow them to drop a ton of logic to deal with null
app_label.

django/db/migrations/operations/base.py

@@ -80,10 +80,10 @@ class Operation:
         """
         return "%s: %s" % (self.__class__.__name__, self._constructor_args)
 
-    def references_model(self, name, app_label=None):
+    def references_model(self, name, app_label):
         """
         Return True if there is a chance this operation references the given
-        model name (as a string), with an optional app label for accuracy.
+        model name (as a string), with an app label for accuracy.
 
         Used for optimization. If in doubt, return True;
         returning a false positive will merely make the optimizer a little
@@ -92,10 +92,10 @@ class Operation:
         """
         return True
 
-    def references_field(self, model_name, name, app_label=None):
+    def references_field(self, model_name, name, app_label):
         """
         Return True if there is a chance this operation references the given
-        field name, with an optional app label for accuracy.
+        field name, with an app label for accuracy.
 
         Used for optimization. If in doubt, return True.
         """

django/db/migrations/operations/fields.py

@@ -28,7 +28,7 @@ class FieldOperation(Operation):
     def is_same_field_operation(self, operation):
         return self.is_same_model_operation(operation) and self.name_lower == operation.name_lower
 
-    def references_model(self, name, app_label=None):
+    def references_model(self, name, app_label):
         name_lower = name.lower()
         if name_lower == self.model_name_lower:
             return True
@@ -36,7 +36,7 @@ class FieldOperation(Operation):
             return field_references_model(self.field, ModelTuple(app_label, name_lower))
         return False
 
-    def references_field(self, model_name, name, app_label=None):
+    def references_field(self, model_name, name, app_label):
         model_name_lower = model_name.lower()
         # Check if this operation locally references the field.
         if model_name_lower == self.model_name_lower:
@@ -376,8 +376,8 @@ class RenameField(FieldOperation):
     def describe(self):
         return "Rename field %s on %s to %s" % (self.old_name, self.model_name, self.new_name)
 
-    def references_field(self, model_name, name, app_label=None):
-        return self.references_model(model_name) and (
+    def references_field(self, model_name, name, app_label):
+        return self.references_model(model_name, app_label) and (
             name.lower() == self.old_name_lower or
             name.lower() == self.new_name_lower
         )

django/db/migrations/operations/models.py

@@ -28,7 +28,7 @@ class ModelOperation(Operation):
     def name_lower(self):
         return self.name.lower()
 
-    def references_model(self, name, app_label=None):
+    def references_model(self, name, app_label):
         return name.lower() == self.name_lower
 
     def reduce(self, operation, app_label):
@@ -99,7 +99,7 @@ class CreateModel(ModelOperation):
     def describe(self):
         return "Create %smodel %s" % ("proxy " if self.options.get("proxy", False) else "", self.name)
 
-    def references_model(self, name, app_label=None):
+    def references_model(self, name, app_label):
         name_lower = name.lower()
         if name_lower == self.name_lower:
             return True
@@ -265,7 +265,7 @@ class DeleteModel(ModelOperation):
         if self.allow_migrate_model(schema_editor.connection.alias, model):
             schema_editor.create_model(model)
 
-    def references_model(self, name, app_label=None):
+    def references_model(self, name, app_label):
         # The deleted model could be referencing the specified model through
         # related fields.
         return True
@@ -402,7 +402,7 @@ class RenameModel(ModelOperation):
         self.new_name_lower, self.old_name_lower = self.old_name_lower, self.new_name_lower
         self.new_name, self.old_name = self.old_name, self.new_name
 
-    def references_model(self, name, app_label=None):
+    def references_model(self, name, app_label):
         return (
             name.lower() == self.old_name_lower or
             name.lower() == self.new_name_lower
@@ -528,7 +528,7 @@ class AlterTogetherOptionOperation(ModelOptionOperation):
     def database_backwards(self, app_label, schema_editor, from_state, to_state):
         return self.database_forwards(app_label, schema_editor, from_state, to_state)
 
-    def references_field(self, model_name, name, app_label=None):
+    def references_field(self, model_name, name, app_label):
         return (
             self.references_model(model_name, app_label) and
             (
@@ -609,7 +609,7 @@ class AlterOrderWithRespectTo(ModelOptionOperation):
     def database_backwards(self, app_label, schema_editor, from_state, to_state):
         self.database_forwards(app_label, schema_editor, from_state, to_state)
 
-    def references_field(self, model_name, name, app_label=None):
+    def references_field(self, model_name, name, app_label):
         return (
             self.references_model(model_name, app_label) and
             (