checks.py 文件源码

def check_dependencies(**kwargs):
    """
    Check that the admin's dependencies are correctly installed.
    """
    errors = []
    # contrib.contenttypes must be installed.
    if not apps.is_installed('django.contrib.contenttypes'):
        missing_app = checks.Error(
            "'django.contrib.contenttypes' must be in INSTALLED_APPS in order "
            "to use the admin application.",
            id="admin.E401",
        )
        errors.append(missing_app)
    # The auth context processor must be installed if using the default
    # authentication backend.
    try:
        default_template_engine = Engine.get_default()
    except Exception:
        # Skip this non-critical check:
        # 1. if the user has a non-trivial TEMPLATES setting and Django
        #    can't find a default template engine
        # 2. if anything goes wrong while loading template engines, in
        #    order to avoid raising an exception from a confusing location
        # Catching ImproperlyConfigured suffices for 1. but 2. requires
        # catching all exceptions.
        pass
    else:
        if ('django.contrib.auth.context_processors.auth'
                not in default_template_engine.context_processors and
                'django.contrib.auth.backends.ModelBackend' in settings.AUTHENTICATION_BACKENDS):
            missing_template = checks.Error(
                "'django.contrib.auth.context_processors.auth' must be in "
                "TEMPLATES in order to use the admin application.",
                id="admin.E402"
            )
            errors.append(missing_template)
    return errors