Merged revisions 87233 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/branches/py3k

........
  r87233 | gregory.p.smith | 2010-12-14 06:38:00 -0800 (Tue, 14 Dec 2010) | 4 lines

  Issue #1731717: Fixed the problem where subprocess.wait() could cause an
  OSError exception when The OS had been told to ignore SIGCLD in our process
  or otherwise not wait for exiting child processes.
........

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 0dd55e0f74e7838f75d138899d9869c78296507a..5684d523952c8905956cac148f6b8b20c5aef7e4 100644 (file)
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -1149,7 +1149,11 @@ class Popen(object):
                 os.close(errpipe_read)
 
             if data:
-                _eintr_retry_call(os.waitpid, self.pid, 0)
+                try:
+                    _eintr_retry_call(os.waitpid, self.pid, 0)
+                except OSError as e:
+                    if e.errno != errno.ECHILD:
+                        raise
                 child_exception = pickle.loads(data)
                 for fd in (p2cwrite, c2pread, errread):
                     if fd is not None:
@@ -1195,7 +1199,15 @@ class Popen(object):
             """Wait for child process to terminate.  Returns returncode
             attribute."""
             if self.returncode is None:
-                pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
+                try:
+                    pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
+                except OSError as e:
+                    if e.errno != errno.ECHILD:
+                        raise
+                    # 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.
+                    sts = 0
                 self._handle_exitstatus(sts)
             return self.returncode
 

diff --git a/Lib/test/subprocessdata/sigchild_ignore.py b/Lib/test/subprocessdata/sigchild_ignore.py
new file mode 100644 (file)
index 0000000..1d03303
--- /dev/null
+++ b/Lib/test/subprocessdata/sigchild_ignore.py
@@ -0,0 +1,6 @@
+import signal, subprocess, sys
+# On Linux this causes os.waitpid to fail with OSError as the OS has already
+# reaped our child process.  The wait() passing the OSError on to the caller
+# and causing us to exit with an error is what we are testing against.
+signal.signal(signal.SIGCLD, signal.SIG_IGN)
+subprocess.Popen([sys.executable, '-c', 'print("albatross")']).wait()

diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 2379b3e5fe4cdd9f96577e609fab8149a265219d..adf00a50a0784e01a22ad89311bebc542cd7a99c 100644 (file)
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -793,6 +793,17 @@ class ProcessTestCase(BaseTestCase):
                 stdout = stdout.rstrip(b'\n\r')
                 self.assertEqual(stdout, value_repr)
 
+        def test_wait_when_sigchild_ignored(self):
+            # NOTE: sigchild_ignore.py may not be an effective test on all OSes.
+            sigchild_ignore = support.findfile("sigchild_ignore.py",
+                                               subdir="subprocessdata")
+            p = subprocess.Popen([sys.executable, sigchild_ignore],
+                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+            stdout, stderr = p.communicate()
+            self.assertEqual(0, p.returncode, "sigchild_ignore.py exited"
+                             " non-zero with this error:\n%s" % stderr)
+
+
     #
     # Windows tests
     #

diff --git a/Misc/NEWS b/Misc/NEWS
index 0f9a78539847810ae1cf85a02fa114ddb21ee002..058b02a6971a4e07d76d09bb71daf70c1196dc9f 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -35,6 +35,10 @@ Library
 
 - Issue #10464: netrc now correctly handles lines with embedded '#' characters.
 
+- Issue #1731717: Fixed the problem where subprocess.wait() could cause an
+  OSError exception when The OS had been told to ignore SIGCLD in our process
+  or otherwise not wait for exiting child processes.
+
 Extensions
 ----------