diff options
Diffstat (limited to 'Lib/typing.py')
| -rw-r--r-- | Lib/typing.py | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/Lib/typing.py b/Lib/typing.py index a51452b..ca47a6f 100644 --- a/Lib/typing.py +++ b/Lib/typing.py @@ -1343,14 +1343,14 @@ def _no_init(self, *args, **kwargs): raise TypeError('Protocols cannot be instantiated') -def _allow_reckless_class_checks(): +def _allow_reckless_class_checks(depth=3): """Allow instance and class checks for special stdlib modules. The abc and functools modules indiscriminately call isinstance() and issubclass() on the whole MRO of a user class, which may contain protocols. """ try: - return sys._getframe(3).f_globals['__name__'] in ['abc', 'functools'] + return sys._getframe(depth).f_globals['__name__'] in ['abc', 'functools'] except (AttributeError, ValueError): # For platforms without _getframe(). return True @@ -1370,6 +1370,14 @@ class _ProtocolMeta(ABCMeta): def __instancecheck__(cls, instance): # We need this method for situations where attributes are # assigned in __init__. + if ( + getattr(cls, '_is_protocol', False) and + not getattr(cls, '_is_runtime_protocol', False) and + not _allow_reckless_class_checks(depth=2) + ): + raise TypeError("Instance and class checks can only be used with" + " @runtime_checkable protocols") + if ((not getattr(cls, '_is_protocol', False) or _is_callable_members_only(cls)) and issubclass(instance.__class__, cls)): |