This PR implements a fix for `multiprocessing.Process` objects; the error occurs when Processes are created using either `fork` or `forkserver` as the `start_method`.
In these instances, the `MainThread` of the newly created `Process` object retains all attributes from its parent's `MainThread` object, including the `native_id` attribute. The resulting behavior is such that the new process' `MainThread` captures an incorrect/outdated `native_id` (the parent's instead of its own).
This change forces the Process object to update its `native_id` attribute during the bootstrap process.
cc @vstinner
https://bugs.python.org/issue38707
Automerge-Triggered-By: @pitrou
(cherry picked from commit c6b20be85c)
Co-authored-by: Jake Tesler <jake.tesler@gmail.com>
In some conditions the standard streams will be None or closed in the child process (for example if using "pythonw" instead of "python" on Windows). Avoid failing with a non-0 exit code in those conditions.
Report and initial patch by poxthegreat.
multiprocessing.Process.is_alive() now removes the process from the
_children set if the process completed.
The change prevents leaking "dangling" processes.
* bpo-30794: added kill() method to multiprocessing.Process
* Added entries to documentation and NEWS
* Refactored test_terminate and test_kill
* Fix SIGTERM and SIGKILL being used on Windows for the tests
* Added "versionadded" marker to the documentation
* Fix trailing whitespace in doc
* Clear potential ref cycle between Process and Process target
Besides Process.join() not being called, this was an indirect cause of bpo-30775.
The threading module already does this.
* Add issue reference
* Fix bpo-30596: Add close() method to multiprocessing.Process
* Raise ValueError if close() is called before the Process is finished running
* Add docs
* Add NEWS blurb
* multiprocessing: open file with closefd=False to avoid ResourceWarning
* _test_multiprocessing: open file with O_EXCL to detect bugs in tests (if a
previous test forgot to remove TESTFN)
* test_sys_exit(): remove TESTFN after each loop iteration
Initial patch written by Serhiy Storchaka.
multiprocessing: Process._bootstrap() keeps a reference to the old process to
delay its finalization until after _run_after_forkers() as been executed. This
change should fix a crash on Mac OS X Tiger when a lock is released after a
fork.
Patch written by Charles-François Nataliv and Antoine Pitrou.
multiprocessing: Process._bootstrap() keeps a reference to the old process to
delay its finalization until after _run_after_forkers() as been executed. This
change should fix a crash on Mac OS X Tiger when a lock is released after a
fork.
Patch written by Charles-François Nataliv and Antoine Pitrou.
