Backport the Popen.poll() protection from subprocess to multiprocessing. See #1731717.
It should fix transient failures on test_multiprocessing.
diff --git a/Lib/multiprocessing/forking.py b/Lib/multiprocessing/forking.py
index 7eda991..a66f7a0 100644
--- a/Lib/multiprocessing/forking.py
+++ b/Lib/multiprocessing/forking.py
@@ -103,7 +103,12 @@
def poll(self, flag=os.WNOHANG):
if self.returncode is None:
- pid, sts = os.waitpid(self.pid, flag)
+ try:
+ pid, sts = os.waitpid(self.pid, flag)
+ except os.error:
+ # Child process not yet created. See #1731717
+ # e.errno == errno.ECHILD == 10
+ return None
if pid == self.pid:
if os.WIFSIGNALED(sts):
self.returncode = -os.WTERMSIG(sts)