Antoine Pitrou <pit...@free.fr> added the comment:
I think pperry nailed it above: > Pdb fails because it is attempting to import the readline module every time > its `trace_dispatch` is called, and the import implementation is not > reentrant in that way. More precisely, _ModuleLock.acquire() in https://github.com/python/cpython/blob/master/Lib/importlib/_bootstrap.py#L101 is not reentrant. If pdb steps into that function and tries to call it again by making an "import" call, `_blocking_on[tid]` will be overwritten and then deleted inside the nested call, so `del _blocking_on` in the enclosing call will raise a KeyError. I think the solution would be either one of: 1) pdb avoids doing anything import-related as part of its step function 2) pdb avoids stepping inside importlib internals (e.g. by blacklisting importlib modules) ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue34609> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
