From 8b4a65c78454c87413ef606e2d9afdc304eea16e Mon Sep 17 00:00:00 2001
From: Segev Finer <segev208@gmail.com>
Date: Fri, 21 Apr 2017 02:18:21 +0300
Subject: [PATCH 1/2] bpo-30121: Fix debug assert in subprocess on Windows

This is caused by closing HANDLEs using os.close which is for CRT file
descriptors and not for HANDLEs.
---
 Lib/subprocess.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 551aad342b8304..010730fdb992c1 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -727,7 +727,10 @@ def __init__(self, args, bufsize=-1, executable=None,
                     to_close.append(self._devnull)
                 for fd in to_close:
                     try:
-                        os.close(fd)
+                        if _mswindows and isinstance(fd, Handle):
+                            fd.Close()
+                        else:
+                            os.close(fd)
                     except OSError:
                         pass
 
@@ -1005,6 +1008,9 @@ def _execute_child(self, args, executable, preexec_fn, close_fds,
                     errwrite.Close()
                 if hasattr(self, '_devnull'):
                     os.close(self._devnull)
+                # Prevent a double close of these handles/fds from __init__
+                # on error.
+                self._closed_child_pipe_fds = True
 
             # Retain the process handle, but close the thread handle
             self._child_created = True

From 6dd5a06c0fc6c30c715e6393a1e5332dc2016b7f Mon Sep 17 00:00:00 2001
From: Segev Finer <segev208@gmail.com>
Date: Tue, 6 Jun 2017 20:24:25 +0300
Subject: [PATCH 2/2] bpo-30121: Suppress debug assertion in test_subprocess
 when ran directly

---
 Lib/test/test_subprocess.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 7fabe6ad765332..9fae5360dd8ed0 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1068,10 +1068,11 @@ def _test_bufsize_equal_one(self, line, expected, universal_newlines):
             p.stdin.write(line) # expect that it flushes the line in text mode
             os.close(p.stdin.fileno()) # close it without flushing the buffer
             read_line = p.stdout.readline()
-            try:
-                p.stdin.close()
-            except OSError:
-                pass
+            with support.SuppressCrashReport():
+                try:
+                    p.stdin.close()
+                except OSError:
+                    pass
             p.stdin = None
         self.assertEqual(p.returncode, 0)
         self.assertEqual(read_line, expected)