diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py index bbe05a550c349c..961d7e5991847a 100644 --- a/Lib/multiprocessing/pool.py +++ b/Lib/multiprocessing/pool.py @@ -203,6 +203,9 @@ def __init__(self, processes=None, initializer=None, initargs=(), processes = os.cpu_count() or 1 if processes < 1: raise ValueError("Number of processes must be at least 1") + if maxtasksperchild is not None: + if not isinstance(maxtasksperchild, int) or maxtasksperchild <= 0: + raise ValueError("maxtasksperchild must be a positive int or None") if initializer is not None and not callable(initializer): raise TypeError('initializer must be a callable') diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py index 1b55cb31c30304..ba488b17920ef7 100644 --- a/Lib/test/_test_multiprocessing.py +++ b/Lib/test/_test_multiprocessing.py @@ -2805,6 +2805,11 @@ def test_pool_worker_lifetime_early_close(self): for (j, res) in enumerate(results): self.assertEqual(res.get(), sqr(j)) + def test_pool_maxtasksperchild_invalid(self): + for value in [0, -1, 0.5, "12"]: + with self.assertRaises(ValueError): + multiprocessing.Pool(3, maxtasksperchild=value) + def test_worker_finalization_via_atexit_handler_of_multiprocessing(self): # tests cases against bpo-38744 and bpo-39360 cmd = '''if 1: diff --git a/Misc/NEWS.d/next/Library/2022-05-30-21-42-50.gh-issue-83658.01Ntx0.rst b/Misc/NEWS.d/next/Library/2022-05-30-21-42-50.gh-issue-83658.01Ntx0.rst new file mode 100644 index 00000000000000..a1873095409803 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-05-30-21-42-50.gh-issue-83658.01Ntx0.rst @@ -0,0 +1 @@ +Make :class:`multiprocessing.Pool` raise an exception if ``maxtasksperchild`` is not ``None`` or a positive int.