showmigrations broken in Django 1.8

[Miguel Araujo]

After upgrading to Django 1.8 and running python manage.py showmigrations it breaks with the following stack trace:

Traceback (most recent call last):
  File "manage.py", line 20, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/map/.virtualenvs/odin/lib/python2.7/site-packages/django/core/management/__init__.py", line 338, in execute_from_command_line
    utility.execute()
  File "/Users/map/.virtualenvs/odin/lib/python2.7/site-packages/django/core/management/__init__.py", line 330, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/map/.virtualenvs/odin/lib/python2.7/site-packages/django/core/management/base.py", line 390, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/map/.virtualenvs/odin/lib/python2.7/site-packages/django/core/management/base.py", line 441, in execute
    output = self.handle(*args, **options)
  File "/Users/map/.virtualenvs/odin/lib/python2.7/site-packages/django/core/management/commands/showmigrations.py", line 32, in handle
    connection = connections[db]
  File "/Users/map/.virtualenvs/odin/lib/python2.7/site-packages/django/db/utils.py", line 234, in __getitem__
    if hasattr(self._connections, alias):
TypeError: hasattr(): attribute name must be string

This can be fixed adding use_argparse = True to show migrations command class, so that add_arguments gets executed settting defaults. This way you get the expected response.

[Tim Graham]

I can't reproduce this using the tutorial project.

[Miguel Araujo]

Ok,

Seems to be an issue with django-configurations which sets a self.option_list making use_argparse = True and then turning the property False and not calling add_arguments.

Related to this:
​https://github.com/jezdez/django-configurations/issues/109

Sorry for the false positive.

Miguel

[Miguel Araujo]

I've been reading some of the commits that moved from optparse to argparse Django's command system:
​https://github.com/django/django/commit/856863860352aa1f0288e6c9168a0e423c4f5184
​https://github.com/django/django/commit/f17b24e407385eb18651bf023a187347aa9c1f75

To be honest if option_list has been replaced by add_arguments method. And in
BaseCommand add_arguments is called only for new system as you can see here:
​https://github.com/django/django/blob/0ed7d155635da9f79d4dd67e4889087d3673c6da/django/core/management/base.py#L308

This change is in reality backwards incompatible (which is not Django's usual philosophy), although the door stays open for still being backwards compatible, but it implies author's work. In my understanding usually Django gives a time gap to adjust apps in situations like this.

As django-configurations is still using optparse and is injecting an option for all commands, which sets the right configuration to use. It is breaking all Django commands.

[Miguel Araujo]

Seem last commit of django-configurations has this handled already:
​https://github.com/jezdez/django-configurations/blob/master/configurations/importer.py#L37