System checks¶

Django's system checks run at start-up - runserver, migrate, check - and refuse what cannot work, before anybody finds it. Each is an error: the project does not start until it is mended.

python manage.py check

id	when
`clearance.E001`	`ACCESS` cannot be read, has a section no installed app reads, or says something that cannot be - a permission not named `app_label.codename`, a model not installed, a status action's field or value its model does not have
`clearance.E002`	a `ScopedQuerySet`'s `scopes` and its `scope_<x>` methods disagree, or its `default_scope` is not offered
`clearance.E003`	a DRF view asking a model's policy serializes the model without leaving out its protected fields
`clearance.E006`	`ClearanceBackend` is not in `AUTHENTICATION_BACKENDS`
`clearance.E007`	`ModelBackend`, or a backend built on it and not on the library's, is beside `ClearanceBackend` - it would hand back every permission taken away
`clearance.E008`	`clearance.roles` or `clearance.translations` is installed without `'clearance'`, or before it
`clearance.E009`	a `PolicyRequiredMixin` view, or a DRF view guarded by a policy, cannot ask one
`clearance.E010`	`ROLE_RESOLVER` or `ROLE_ATTRIBUTE` cannot be used
`clearance.E011`	`CLEARANCE` is not a dictionary, has a key the library does not know, or a value it cannot use
`clearance.E012`	a field protected in code is not a field of its model, or cannot be protected - the primary key, the password, a relation of another model - or its permission is another model's too
`clearance.E013`	an action found in the code cannot make a permission - its policy has no model, or the name is too long
`clearance.E014`	a model declares its permissions with `build_permissions` but keeps Django's own - `default_permissions = ()` is missing
`clearance.E015`	a status action declared in code names a field or a value its model does not have
`clearance.E016`	an admin site is not the library's: its pages would not ask the policies, and would show every protected field

E004 and E005 are retired and never raised. E004 refused a scoped view over a plain manager, and every queryset can be scoped now; E005 checked ceilings written in code, and ceilings are in the database now.

What only the database can tell¶

A system check sees the code. What the rows hold is clearance_check's to say.