Issue #8780: Fix a regression introduced by r78946 in subprocess on Windows
Ensure that stdout / stderr is inherited from the parent if stdout=PIPE /
stderr=PIPE is not used.
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index adbee0b..ad6fd1f 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -843,7 +843,7 @@
# Process startup details
if startupinfo is None:
startupinfo = STARTUPINFO()
- if None not in (p2cread, c2pwrite, errwrite):
+ if -1 not in (p2cread, c2pwrite, errwrite):
startupinfo.dwFlags |= _subprocess.STARTF_USESTDHANDLES
startupinfo.hStdInput = p2cread
startupinfo.hStdOutput = c2pwrite