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.

2 files changed, 16 insertions, 0 deletions

diff --git a/Lib/test/subprocessdata/sigchild_ignore.py b/Lib/test/subprocessdata/sigchild_ignore.py
new file mode 100644
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 0804a13..1e97bac 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1073,6 +1073,16 @@ class POSIXProcessTestCase(BaseTestCase):
                         close_fds=False, pass_fds=(fd, )))
             self.assertIn('overriding close_fds', str(context.warning))
 
+    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)
+
 
 @unittest.skipUnless(mswindows, "Windows specific tests")
 class Win32ProcessTestCase(BaseTestCase):