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

[gregory.p.smith]

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