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Wait, how come thereturncode is not catching this kind of issue. I remember we changed thesubprocess call but I don't remember why we left it as is.

1. Can you also use the issue number we used for adding this test?
2. Can you narrow down the exception being caught instead of a bareexcept? or find a way to avoid a try-except and use another feature ofsubprocess if possible?

cc@encukou (I don't remember why we didn't catch this)

The trace is actually from 3.12.9, but the subprocess call throws exception also in 3.13 and 3.14-rc although I didn't try to run the testsuite in those.
The test was introduced based ongh-126554 and backported to 3.12 ingh-127764.
I can also just target 3.12 branch if it's not a problem for newer branches.

I'll rewrite this to catch justFileNotFoundError

Beautified by addingFileNotFoundError exception type

Meanwhile I retested also 3.13.2, so I guess it's valid for all releases.

======================================================================ERROR: test_null_dlsym (test.test_ctypes.test_dlerror.TestNullDlsym.test_null_dlsym)----------------------------------------------------------------------Traceback (most recent call last):  File "/usr/lib/python3.13/test/test_ctypes/test_dlerror.py", line 61, in test_null_dlsym    retcode = subprocess.call(["gcc", "--version"],                              stdout=subprocess.DEVNULL,                              stderr=subprocess.DEVNULL)  File "/usr/lib/python3.13/subprocess.py", line 397, in call    with Popen(*popenargs, **kwargs) as p:         ~~~~~^^^^^^^^^^^^^^^^^^^^^^  File "/usr/lib/python3.13/subprocess.py", line 1038, in __init__    self._execute_child(args, executable, preexec_fn, close_fds,    ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                        pass_fds, cwd, env,                        ^^^^^^^^^^^^^^^^^^^    ...<5 lines>...                        gid, gids, uid, umask,                        ^^^^^^^^^^^^^^^^^^^^^^                        start_new_session, process_group)                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  File "/usr/lib/python3.13/subprocess.py", line 1974, in _execute_child    raise child_exception_type(errno_num, err_msg, err_filename)FileNotFoundError: [Errno 2] No such file or directory: 'gcc'

Ok, actually thereis a way to make it work without a try-except: We need to pass theshell=True parameter.However it appears that the following happens:

>>>subprocess.call(["gcc","--version"],stdout=subprocess.DEVNULL,stderr=subprocess.DEVNULL)0>>>subprocess.call(["gcc","--version"],stdout=subprocess.DEVNULL,stderr=subprocess.DEVNULL,shell=True)1

So, we need to be a bit more careful with the actual return code! So, instead I either indeed suggest using aFileNotFoundError guard. Note that usingwhich could work but this utility is not present everywhere:

subprocess.call(["which","abc"],stdout=subprocess.DEVNULL,stderr=subprocess.DEVNULL)# == 1subprocess.call(["which","gcc"],stdout=subprocess.DEVNULL,stderr=subprocess.DEVNULL)# == 0

So, let's use the guard.

There isshutil.which, but, catching the error is more appropriate here.

Perhaps it's time to add a test helper to find gcc/clang, and skip test if it's not available. (But that would be for a new PR.)

Thanks@petermarko for the PR, and@encukou for merging it 🌮🎉.. I'm working now to backport this PR to: 3.12, 3.13.
🐍🍒⛏🤖

GH-129944 is a backport of this pull request to the3.13 branch.

Thank you for the report & fix,@petermarko!

GH-129945 is a backport of this pull request to the3.12 branch.

⚠️⚠️⚠️ Buildbot failure⚠️⚠️⚠️

Hi! The buildbotAMD64 Debian root 3.13 has failed when building commitcef406b.

What do you need to do:

1. Don't panic.
2. Checkthe 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/1441/builds/897) and take a look at the build logs.
4. Check if the failure is related to this commit (cef406b) 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/1441/builds/897

Failed tests:

• test_os

Failed subtests:

• test_timerfd_ns_select - test.test_os.TimerfdTests.test_timerfd_ns_select

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

==

Traceback (most recent call last):  File"/root/buildarea/3.13.angelico-debian-amd64/build/Lib/test/test_os.py", line4450, intest_timerfd_ns_selectself.assertEqual(self.read_count_signaled(fd),1)~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^AssertionError:3 != 1Traceback (most recent call last):  File"/root/buildarea/3.13.angelico-debian-amd64/build/Lib/test/test_os.py", line4450, intest_timerfd_ns_selectself.assertEqual(self.read_count_signaled(fd),1)~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^AssertionError:4 != 1