[3.14] gh-74389: gh-70560: subprocess.Popen.communicate() now ignores stdin.flush error when closed (GH-142061) (#142064)

gh-74389: gh-70560: subprocess.Popen.communicate() now ignores stdin.flush error when closed (GH-142061)

gh-70560: gh-74389: subprocess.Popen.communicate() now ignores stdin.flush error when closed

with a unittest and news entry.
(cherry picked from commit 923056b2d4)

Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com>

Lib/subprocess.py

@@ -2097,6 +2097,10 @@ def _communicate(self, input, endtime, orig_timeout):
                     self.stdin.flush()
                 except BrokenPipeError:
                     pass  # communicate() must ignore BrokenPipeError.
+                except ValueError:
+                    # ignore ValueError: I/O operation on closed file.
+                    if not self.stdin.closed:
+                        raise
                 if not input:
                     try:
                         self.stdin.close()