Issue #25654:
* 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.
diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index bf25f3f..6440f5c 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -2694,7 +2694,7 @@
in issues with processes-in-processes. This has been changed to::
sys.stdin.close()
- sys.stdin = open(os.devnull)
+ sys.stdin = open(os.open(os.devnull, os.O_RDONLY), closefd=False)
Which solves the fundamental issue of processes colliding with each other
resulting in a bad file descriptor error, but introduces a potential danger