Method _get_expr_references

django/db/models/base.py:2488–2501

(cls, expr)

    @classmethod
    def _get_expr_references(cls, expr):
        if isinstance(expr, Q):
            for child in expr.children:
                if isinstance(child, tuple):
                    lookup, value = child
                    yield tuple(lookup.split(LOOKUP_SEP))
                    yield from cls._get_expr_references(value)
                else:
                    yield from cls._get_expr_references(child)
        elif isinstance(expr, F):
            yield tuple(expr.name.split(LOOKUP_SEP))
        elif hasattr(expr, "get_source_expressions"):
            for src_expr in expr.get_source_expressions():
                yield from cls._get_expr_references(src_expr)

    @classmethod
    def _check_constraints(cls, databases):