[Python-checkins] cpython (2.7): Fixes issue #14396: Handle the odd rare case of waitpid returning 0

Sun Nov 11 06:13:37 CET 2012

http://hg.python.org/cpython/rev/82711f5ab507
changeset: 80367:82711f5ab507
branch: 2.7
parent: 80361:9b711422c98f
user: Gregory P. Smith <greg at krypto.org>
date: Sat Nov 10 21:13:20 2012 -0800
summary:
 Fixes issue #14396: Handle the odd rare case of waitpid returning 0
when not expected in subprocess.Popen.wait().
files:
 Lib/subprocess.py | 8 ++++++--
 Misc/NEWS | 3 +++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -1303,7 +1303,7 @@
 def wait(self):
 """Wait for child process to terminate. Returns returncode
 attribute."""
- if self.returncode is None:
+ while self.returncode is None:
 try:
 pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
 except OSError as e:
@@ -1312,8 +1312,12 @@
 # This happens if SIGCLD is set to be ignored or waiting
 # for child processes has otherwise been disabled for our
 # process. This child is dead, we can't get the status.
+ pid = self.pid
 sts = 0
- self._handle_exitstatus(sts)
+ # Check the pid and loop as waitpid has been known to return
+ # 0 even without WNOHANG in odd situations. issue14396.
+ if pid == self.pid:
+ self._handle_exitstatus(sts)
 return self.returncode
 
 
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -143,6 +143,9 @@
 Library
 -------
 
+- Issue #14396: Handle the odd rare case of waitpid returning 0 when not
+ expected in subprocess.Popen.wait().
+
 - Issue #16411: Fix a bug where zlib.decompressobj().flush() might try to access
 previously-freed memory. Patch by Serhiy Storchaka.
 
-- 
Repository URL: http://hg.python.org/cpython
