id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
24559	MigrationLoader.load_disk ImportError handling differs under py3/pypy vs py2	Keryn Knight	Jon Dufresne	"Currently, within `load_disk`, the following happens:

{{{
            try:
                module = import_module(module_name)
            except ImportError as e:
                # I hate doing this, but I don't want to squash other import errors.
                # Might be better to try a directory check directly.
                if ""No module named"" in str(e) and MIGRATIONS_MODULE_NAME in str(e):
                    self.unmigrated_apps.add(app_config.label)
                    continue
                raise
}}}

However, the [https://github.com/django/django/blob/2832a9b028c267997b2fd3dd0989670d57cdd08f/django/db/migrations/loader.py#L73 if statement] behaves differently under pypy & python3, because the exception string is different.

Under python2, the following yields
{{{
>>> from importlib import import_module
>>> importlib('test_auth.migrations')
ImportError: No module named test_auth.migrations
}}}

which would hit both parts of the conditional, and end up in `self.unmigrated_apps`

However, under python3.3.3 the exception is:
{{{
ImportError: No module named 'test_auth'
}}}
and under pypy 2.2.1 (for python 2.7.3) the exception is:
{{{
ImportError: No module named test_auth
}}}
(same as py3k, sans quotes)

Neither of these would end up `self.unmigrated_apps` because `MIGRATIONS_MODULE_NAME` doesn't appear in the string representation, though I suspect `import_module('testauthmigrations')` '''would''' work.

I originally noticed this because of a [https://travis-ci.org/kezabelle/django-typesafetynet/builds/55545694 travis build] for a toy project, so it may not be a problem in practice, but it is at least inconsistent."	Bug	closed	Migrations	dev	Normal	fixed		django@…	Ready for checkin	1	0	0	0	0	0