RunSQL Bug Django 1.7

[Aryeh Hillman]

Django migrations are wonderful, but I believe I have found a bug. The essence of what I am trying to do here: rename all tables starting with the name "hello" (i.e. hello_1, hello2_, hello_3, ...) to start with the name "goodbye (goodbye_1, goodbye_2, goodbye_3, ...), which could be very helpful when renaming an application.

Here's how to reproduce (there is probably a more minimal case):

1. Install this function at a shell for PostgreSQL (very handy for

CREATE FUNCTION exec(text) returns text language plpgsql volatile
  AS $f$
    BEGIN
      EXECUTE $1;
      RETURN $1;
    END;
$f$;

source: ​http://wiki.postgresql.org/wiki/Dynamic_DDL

2. Write a RunSQL operation to help rename some tables

class Migration(migrations.Migration):
...
    operations = [
        migrations.RunPython(
            code=x
        ),
        migrations.RunSQL(
            sql="""select exec(format('alter table %I rename to %I', tablename, regexp_replace(tablename, '^hello, 'goodbye'))) from pg_tables where tablename like 'hello%';"""
        ),
    ]
...

3. Run the migration. I got this error:

Traceback (most recent call last):
  File "./manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 160, in handle
    executor.migrate(targets, plan, fake=options.get("fake", False))
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/db/migrations/executor.py", line 63, in migrate
    self.apply_migration(migration, fake=fake)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/db/migrations/executor.py", line 97, in apply_migration
    migration.apply(project_state, schema_editor)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/db/migrations/migration.py", line 107, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/db/migrations/operations/special.py", line 69, in database_forwards
    schema_editor.execute(statement)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/db/backends/schema.py", line 98, in execute
    cursor.execute(sql, params)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/db/backends/utils.py", line 81, in execute
    return super(CursorDebugWrapper, self).execute(sql, params)
  File "/Users/abhillman/stable_env/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
    return self.cursor.execute(sql, params)
IndexError: list index out of range

Not sure what's going on here. Could it be the custom PGSQL function?