diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py index c03c859baa795b..271ba3fd325138 100644 --- a/Lib/multiprocessing/process.py +++ b/Lib/multiprocessing/process.py @@ -61,7 +61,7 @@ def parent_process(): def _cleanup(): # check for processes which have finished for p in list(_children): - if p._popen.poll() is not None: + if (child_popen := p._popen) and child_popen.poll() is not None: _children.discard(p) # diff --git a/Misc/NEWS.d/next/Library/2023-05-16-10-07-16.gh-issue-104536.hFWD8f.rst b/Misc/NEWS.d/next/Library/2023-05-16-10-07-16.gh-issue-104536.hFWD8f.rst new file mode 100644 index 00000000000000..b0f5d78f7e61da --- /dev/null +++ b/Misc/NEWS.d/next/Library/2023-05-16-10-07-16.gh-issue-104536.hFWD8f.rst @@ -0,0 +1,3 @@ +Fix a race condition in the internal :mod:`multiprocessing.process` cleanup +logic that could manifest as an unintended ``AttributeError`` when calling +``process.close()``.