expressions.py 文件源码

def resolve_expression(self, query=None, allow_joins=True, reuse=None, summarize=False, for_save=False):
        copy = self.copy()
        copy.col = query.resolve_ref(self.lookup, allow_joins, reuse, summarize)
        field = copy.col.output_field
        assert isinstance(field, fields.DateField), "%r isn't a DateField." % field.name
        if settings.USE_TZ:
            assert not isinstance(field, fields.DateTimeField), (
                "%r is a DateTimeField, not a DateField." % field.name
            )
        return copy