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
29386	Meta Inheritance for default_permissions	Clayton Daley	nobody	"I add Read/Browse permissions to my models that I enforce in my views.  For some reason, `default_permissions` isn't inheriting in the way I would expect.  Nor does the Meta Inheritance section of the documentation say anything to suggest this should not be valid.

Given something like:

{{{
class BreadMetaMixin(object):
    # ACTION_EDIT aliases ""change"" for BREAD semantics, see http://paul-m-jones.com/archives/291
    default_permissions = (ACTION_BROWSE, ACTION_READ, ACTION_EDIT, ACTION_ADD, ACTION_DELETE)

class Encounter(AbstractParentModel):
    class Meta(BreadMetaMixin, AbstractParentModel.Meta):
        pass

class Admission(Encounter):
    class Meta(Encounter.Meta):
        # also reproduced with non-proxy model
        proxy = True
}}}

When I `makemigrations`, Encounter detects the new permissions...

{{{
...
    operations = [
        migrations.CreateModel(
            name='Encounter',
...
            options={
                'default_permissions': ('browse', 'read', 'change', 'add', 'delete'),
                'abstract': False,
            },
...
}}}

but Admissions does not:

{{{
...
    operations = [
        migrations.CreateModel(
            name='Admission',
...
            options={
                'abstract': False,
                'proxy': True,  # also verified with non-proxy model
                'indexes': [],
            },
...
}}}

It's possible that this hasn't come up because it's masked by #11154, but it affects non-proxy models as well.  I noticed it because I'm working around #11154 using a migration like:

{{{
def add_proxy_permissions(apps, schema_editor):
    """"""Workaround https://code.djangoproject.com/ticket/11154 by manually creating the required permissions.""""""
    ContentType = apps.get_model('contenttypes', 'ContentType')
    Permission = apps.get_model('auth', 'Permission')
    for model in ['Admission']:
        class_ = apps.get_model('task_manager', model)
        content_type = ContentType.objects.get_for_model(class_, for_concrete_model=False)
        for perm in class_._meta.default_permissions:
            Permission.objects.get_or_create(
                content_type=content_type,
                codename='{}_{}'.format(perm, model.lower()),
            )
}}}

This works great on two meta models where `BreadMetaMixin` is included directly (e.g. `UserProxy` wraps `auth.models.User` and includes `BreadMetaMixin`).  When I moved the code over to `Admission`, however, it wasn't working correctly.  If I mixin `BreadMetaMixin` directly, it works fine so I've narrowed it down to a Meta Inheritance issue.  "	Bug	new	Uncategorized	1.11	Normal				Unreviewed	0	0	0	0	0	0