Fix https://bugs.python.org/issue32270 to get Python 3.7.2 test_subprocess working.

CHANGES.rst

@@ -25,6 +25,11 @@
 - The result of ``gevent.ssl.SSLSocket.makefile()`` can be used as a
   context manager on Python 2.
 
+- subprocess: No longer close redirected FDs if they are in
+  ``pass_fds``. This is `a bugfix from Python 3.7
+  <https://bugs.python.org/issue32270>`_ applied to all versions
+  gevent runs on.
+
 1.4.0 (2019-01-04)
 ==================
 

src/gevent/_sslgte279.py

@@ -56,9 +56,9 @@ if 'namedtuple' in __all__:
 
 # See notes in _socket2.py. Python 3 returns much nicer
 # `io` object wrapped around a SocketIO class.
-assert not hasattr(__ssl__._fileobject, '__enter__') # pylint:disable=used-before-assignment
+assert not hasattr(__ssl__._fileobject, '__enter__') # pylint:disable=no-member
 
-class _fileobject(__ssl__._fileobject): # pylint:no-member
+class _fileobject(__ssl__._fileobject): # pylint:disable=no-member
 
     def __enter__(self):
         return self

src/gevent/subprocess.py

@@ -1376,8 +1376,10 @@ class Popen(object):
                             # is possible that it is overwritten (#12607).
                             if c2pwrite == 0:
                                 c2pwrite = os.dup(c2pwrite)
+                                _set_inheritable(c2pwrite, False)
                             while errwrite in (0, 1):
                                 errwrite = os.dup(errwrite)
+                                _set_inheritable(errwrite, False)
 
                             # Dup fds for child
                             def _dup2(existing, desired):
@@ -1401,11 +1403,18 @@ class Popen(object):
 
                             # Close pipe fds.  Make sure we don't close the
                             # same fd more than once, or standard fds.
-                            closed = set([None])
-                            for fd in [p2cread, c2pwrite, errwrite]:
-                                if fd not in closed and fd > 2:
-                                    os.close(fd)
-                                    closed.add(fd)
+                            if not PY3:
+                                closed = set([None])
+                                for fd in [p2cread, c2pwrite, errwrite]:
+                                    if fd not in closed and fd > 2:
+                                        os.close(fd)
+                                        closed.add(fd)
+
+                            # Python 3 (with a working set_inheritable):
+                            # We no longer manually close p2cread,
+	                        # c2pwrite, and errwrite here as
+	                        # _close_open_fds takes care when it is
+	                        # not already non-inheritable.
 
                             if cwd is not None:
                                 try: