bpo-30418: Popen.communicate() always ignore EINVAL (#2002) (#2006)

On Windows, subprocess.Popen.communicate() now also ignore EINVAL
on stdin.write() if the child process is still running but closed the
pipe.
(cherry picked from commit d52aa31)

Author: vstinner

Lib/subprocess.py

@@ -720,10 +720,11 @@ def _communicate(self, input):
                         if e.errno == errno.EPIPE:
                             # communicate() should ignore broken pipe error
                             pass
-                        elif (e.errno == errno.EINVAL
-                              and self.poll() is not None):
-                            # Issue #19612: stdin.write() fails with EINVAL
-                            # if the process already exited before the write
+                        elif e.errno == errno.EINVAL:
+                            # bpo-19612, bpo-30418: On Windows, stdin.write()
+                            # fails with EINVAL if the child process exited or
+                            # if the child process is still running but closed
+                            # the pipe.
                             pass
                         else:
                             raise

Misc/NEWS

@@ -49,6 +49,9 @@ Extension Modules
 Library
 -------
 
+- bpo-30418: On Windows, subprocess.Popen.communicate() now also ignore EINVAL
+  on stdin.write() if the child process is still running but closed the pipe.
+
 - bpo-30378: Fix the problem that logging.handlers.SysLogHandler cannot
   handle IPv6 addresses.