A

Agreed the regression seems to stem from the change in PathDistribution.metadata to return None. It does correctly return None, but downstream properties like .name, .version, and .requires weren't updated to...

I can reproduce this with the code snippet above. It looks like `Py_buffer` handling in `_pickle.c` isn't accounting for the buffer being released during the callback. I'd be happy to...

@picnixz because `PickleBuffer.release()` explicitly signals that the buffer is released, my thinking was that raising an error would be more semantically correct here than silently keeping the memory alive. RE:...

@picnixz Yeah I had re-pro'd and was starting to poke around working on a patch based on your guidance. Happy to take the above and implement. I'll make a PR...

@picnixz The above should be nearly exactly your recommended fix above, which did indeed fix this. I say nearly because I needed to change `PyBUF_SIMPLE` to `PyBUF_FULL_RO` because `PyBUF_SIMPLE` seemed...