checks.py 文件源码

def _check_list_filter_item(self, obj, model, item, label):
        """
        Check one item of `list_filter`, i.e. check if it is one of three options:
        1. 'field' -- a basic field filter, possibly w/ relationships (e.g.
           'field__rel')
        2. ('field', SomeFieldListFilter) - a field-based list filter class
        3. SomeListFilter - a non-field list filter class
        """

        from django.contrib.admin import ListFilter, FieldListFilter

        if callable(item) and not isinstance(item, models.Field):
            # If item is option 3, it should be a ListFilter...
            if not issubclass(item, ListFilter):
                return must_inherit_from(parent='ListFilter', option=label,
                                         obj=obj, id='admin.E113')
            # ...  but not a FieldListFilter.
            elif issubclass(item, FieldListFilter):
                return [
                    checks.Error(
                        "The value of '%s' must not inherit from 'FieldListFilter'." % label,
                        obj=obj.__class__,
                        id='admin.E114',
                    )
                ]
            else:
                return []
        elif isinstance(item, (tuple, list)):
            # item is option #2
            field, list_filter_class = item
            if not issubclass(list_filter_class, FieldListFilter):
                return must_inherit_from(parent='FieldListFilter', option='%s[1]' % label, obj=obj, id='admin.E115')
            else:
                return []
        else:
            # item is option #1
            field = item

            # Validate the field string
            try:
                get_fields_from_path(model, field)
            except (NotRelationField, FieldDoesNotExist):
                return [
                    checks.Error(
                        "The value of '%s' refers to '%s', which does not refer to a Field." % (label, field),
                        obj=obj.__class__,
                        id='admin.E116',
                    )
                ]
            else:
                return []