Closed
Description
Bug report
Bug description:
When _abc exists, abc.ABCMeta.__instancecheck__ is a thin wrapper of _abc._abc_instancecheck.
Due to the difference of behavior, it seems to related to importlib test
import pathlib
from importlib.resources.readers import MultiplexedPath
from importlib.resources.abc import Traversable
import _abc # C implementation
import _py_abc # Pure Python implementation
def test_abc_difference():
mp = MultiplexedPath(pathlib.Path('/tmp'))
print(f"Object: {type(mp).__name__}")
print(f"ABC: {Traversable.__name__}")
# C implementation (_abc_instancecheck)
try:
result_c = _abc._abc_instancecheck(Traversable, mp)
print(f"C _abc_instancecheck result: {result_c}")
except Exception as e:
print(f"C _abc_instancecheck error: {e}")
# Pure Python implementation (_py_abc.ABCMeta.__instancecheck__)
try:
result_py = _py_abc.ABCMeta.__instancecheck__(Traversable, mp)
print(f"Python _py_abc result: {result_py}")
except Exception as e:
print(f"Python _py_abc error: {e}")
if __name__ == "__main__":
test_abc_difference()The result:
Object: MultiplexedPath
ABC: Traversable
C _abc_instancecheck error: Protocols with non-method members don't support issubclass(). Non-method members: 'name'.
Python _py_abc error: type object 'Traversable' has no attribute '_abc_cache'
Reproducible on 3.13 and main
CPython versions tested on:
CPython main branch
Operating systems tested on:
macOS