gh-141659: Fix bad file descriptors from subprocess in AIX

[ayappanec]

This PR is to fix the problem mentioned in the issue #141659

• Issue: Bad file descriptor errors from subprocess module in AIX #141659

[serhiy-storchaka]

LGTM after fixing punctuation.

[ayappanec]

Updated the PR with requested changes.

[miss-islington-app]

Thanks @ayappanec for the PR, and @serhiy-storchaka for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14.
🐍🍒⛏🤖

[bedevere-app]

GH-141738 is a backport of this pull request to the 3.14 branch.

[miss-islington-app]

Sorry, @ayappanec and @serhiy-storchaka, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 92c5de73b8d7526326c865b1a669b868f0d40c1e 3.13

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot ARM64 macOS 3.x (tier-2) has failed when building commit 92c5de7.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/725/builds/12371) and take a look at the build logs.
4. Check if the failure is related to this commit (92c5de7) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/725/builds/12371

Failed tests:

• test_ssl

Summary of the results of the build (if available):

==

Click to see traceback logs

remote: Enumerating objects: 9, done.        
remote: Counting objects:  12% (1/8)        
remote: Counting objects:  25% (2/8)        
remote: Counting objects:  37% (3/8)        
remote: Counting objects:  50% (4/8)        
remote: Counting objects:  62% (5/8)        
remote: Counting objects:  75% (6/8)        
remote: Counting objects:  87% (7/8)        
remote: Counting objects: 100% (8/8)        
remote: Counting objects: 100% (8/8), done.        
remote: Compressing objects:  20% (1/5)        
remote: Compressing objects:  40% (2/5)        
remote: Compressing objects:  60% (3/5)        
remote: Compressing objects:  80% (4/5)        
remote: Compressing objects: 100% (5/5)        
remote: Compressing objects: 100% (5/5), done.        
remote: Total 9 (delta 3), reused 3 (delta 3), pack-reused 1 (from 1)        
From https://github.com/python/cpython
 * branch                    main       -> FETCH_HEAD
Note: switching to '92c5de73b8d7526326c865b1a669b868f0d40c1e'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at 92c5de73b8d gh-141659: Fix bad file descriptor error in subprocess on AIX (GH-141660)
Switched to and reset branch 'main'

make: *** [buildbottest] Error 2

[serhiy-storchaka]

@ayappanec, do you mind to create a backport to 3.13? Otherwise I'll do this.

[ayappanec]

@ayappanec, do you mind to create a backport to 3.13? Otherwise I'll do this.

@serhiy-storchaka Sure., I will do it.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot ARM64 macOS 3.14 (tier-2) has failed when building commit 7cb15f9.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1772/builds/724) and take a look at the build logs.
4. Check if the failure is related to this commit (7cb15f9) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1772/builds/724

Failed tests:

• test_urllib2net
• test_ssl

Summary of the results of the build (if available):

==

Click to see traceback logs

remote: Enumerating objects: 9, done.        
remote: Counting objects:  12% (1/8)        
remote: Counting objects:  25% (2/8)        
remote: Counting objects:  37% (3/8)        
remote: Counting objects:  50% (4/8)        
remote: Counting objects:  62% (5/8)        
remote: Counting objects:  75% (6/8)        
remote: Counting objects:  87% (7/8)        
remote: Counting objects: 100% (8/8)        
remote: Counting objects: 100% (8/8), done.        
remote: Compressing objects:  25% (1/4)        
remote: Compressing objects:  50% (2/4)        
remote: Compressing objects:  75% (3/4)        
remote: Compressing objects: 100% (4/4)        
remote: Compressing objects: 100% (4/4), done.        
remote: Total 9 (delta 4), reused 7 (delta 4), pack-reused 1 (from 1)        
From https://github.com/python/cpython
 * branch                    3.14       -> FETCH_HEAD
Note: switching to '7cb15f93fe53931aae9fc0e61e07354fd66cab9c'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by switching back to a branch.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -c with the switch command. Example:

  git switch -c <new-branch-name>

Or undo this operation with:

  git switch -

Turn off this advice by setting config variable advice.detachedHead to false

HEAD is now at 7cb15f93fe5 [3.14] gh-141659: Fix bad file descriptor error in subprocess on AIX (GH-141660) (GH-141738)
Switched to and reset branch '3.14'

make: *** [buildbottest] Error 2

[ayappanec]

Tried backporting to 3.13 but encountered below error.,

Now backporting '92c5de73b8d7526326c865b1a669b868f0d40c1e' into '3.13'
Error cherry-pick 92c5de73b8d7526326c865b1a669b868f0d40c1e.
CONFLICT (file location): Misc/NEWS.d/next/Core_and_Builtins/2025-11-17-08-16-30.gh-issue-141659.QNi9Aj.rst added in 92c5de73b8d (gh-141659: Fix bad file descriptor error in subprocess on AIX (GH-141660)) inside a directory that was renamed in HEAD, suggesting it should perhaps be moved to Misc/NEWS.d/next/Core and Builtins/2025-11-17-08-16-30.gh-issue-141659.QNi9Aj.rst.
Auto-merging Modules/_posixsubprocess.c
error: could not apply 92c5de73b8d... gh-141659: Fix bad file descriptor error in subprocess on AIX (GH-141660)

The NEWS entry file has "Core_and_Builtins" but it is suggesting "Core and Builtins"

[serhiy-storchaka]

Oh, I have not noticed this, but it should be "Library", not "Core_and_Builtins", and not "Core and Builtins". Could you create a PR for main to move the NEWS file to the correct directory?

[ayappanec]

Oh, I have not noticed this, but it should be "Library", not "Core_and_Builtins", and not "Core and Builtins". Could you create a PR for main to move the NEWS file to the correct directory?

I just a created a PR for this.

[bedevere-app]

GH-141828 is a backport of this pull request to the 3.13 branch.