migration RunPython operation ignores db router allow_migrate

[dikamilo]

I wrote custom router for SaaS architecture to handle different databases and custom management command to apply migrations for all databases. I'm sure that this router and command works properly.

All migrations works fine except migrations with RunPython command in operations - that migrations are executed ignoring allow_migrate policy in database router.

For example in one of my app i have several migrations generated by django (manage.py makemigrations). My router checks if given app models should be in given database and if it return False, django not create table, not change schema etc. All works just fine and model is not in database. But if I create empty migration and add RunPython operation that add initial data to database for given model, django execute this migration throwing out error django.db.utils.OperationalError: no such table.

I checked django code and for example in AlterModelTable operation database_forwards method uses self.allowed_to_migrate:

def database_forwards(self, app_label, schema_editor, from_state, to_state):
        old_apps = from_state.render()
        new_apps = to_state.render()
        old_model = old_apps.get_model(app_label, self.name)
        new_model = new_apps.get_model(app_label, self.name)
        if self.allowed_to_migrate(schema_editor.connection.alias, new_model):
            schema_editor.alter_db_table(
                new_model,
                old_model._meta.db_table,
                new_model._meta.db_table,
            )

To compare RunPython database_forwards method look like this (cut comments):

def database_forwards(self, app_label, schema_editor, from_state, to_state):
        self.code(from_state.render(), schema_editor)

I think it's a bug and RunPython command should use self.allowed_to_migrate too.

[Tim Graham]

Please see #22583 and #23749. I think this is a duplicate of those issues. Thanks!