Some errors are not caught by `test_os.LoginTests.test_getlogin`

[yihong0618]

Bug report

Bug description:

[hyi@rocky cpython]$ ./python -m unittest test.test_os.test_os.LoginTests.test_getlogin -v

test_getlogin (test.test_os.test_os.LoginTests.test_getlogin) ... ERROR

======================================================================
ERROR: test_getlogin (test.test_os.test_os.LoginTests.test_getlogin)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/hyi/cpython/Lib/test/test_os/test_os.py", line 3204, in test_getlogin
    user_name = os.getlogin()
FileNotFoundError: [Errno 2] No such file or directory

----------------------------------------------------------------------
Ran 1 test in 0.002s

FAILED (errors=1)

This test bring back in patch #139498

but in some system there will be a FileNotFoundError
since FileNotFoundError is a subclass of OSError
but the errno maybe ENOENT in some linux

cc @vstinner

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-139935: fix flaky test for test_getlogin #139936
• gh-139935: do not skip test on real errors in os.getlogin #139953

[vstinner]

Oh, that's surprising. What is your OS name and version? What are the output of "id" and "whoami" commands? Does the test still fail after calling these commands?

[yihong0618]

Oh, that's surprising. What is your OS name and version? What are the output of "id" and "whoami" commands? Does the test still fail after calling these commands?

Hi I am using orbstack on mac

this works

>>> import getpass
>>> print(getpass.getuser())
hyi

this not

Python 3.15.0a0 (heads/main:34503111fe2, Oct 11 2025, 16:02:35) [GCC 11.5.0 20240719 (Red Hat 11.5.0-5)] on linux
Type "help", "copyright", "credits" or "license" for more information.
Ctrl click to launch VS Code Native REPL
>>> import os
>>> os.get_
os.get_blocking(       os.get_exec_path(      os.get_inheritable(    os.get_terminal_size(  
>>> os.getlogin()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    os.getlogin()
    ~~~~~~~~~~~^^
FileNotFoundError: [Errno 2] No such file or directory
>>> 
>>> 

the printout as show:

[hyi@rocky ~]$ id
uid=501(hyi) gid=501(hyi) groups=501(hyi),4(adm),10(wheel),39(video)
[hyi@rocky ~]$ whoami
hyi

[hyi@rocky ~]$ 
[hyi@rocky ~]$ uname -r
6.15.11-orbstack-00542-g4f455d264886
[hyi@rocky ~]$ uname -a
Linux rocky 6.15.11-orbstack-00542-g4f455d264886 #1 SMP PREEMPT Tue Sep 30 00:46:49 UTC 2025 aarch64 aarch64 aarch64 GNU/Linux
[hyi@rocky ~]$ cat /proc/self/loginuid
cat: /proc/self/loginuid: No such file or directory
[hyi@rocky ~]$ 

---

some digging

python use getlogin_r

the errors may come more check doc:

https://linux.die.net/man/3/getlogin_r

[picnixz]

I think we should just catch all errors that are documented on the manpage. Some are POSIX-defined and others are Linux-only.

[yihong0618]

I think we should just catch all errors that are documented on the manpage. Some are POSIX-defined and others are Linux-only.

Done and checked the errno file all ERROR enum do not need special check

[picnixz]

Thank you for the report & fix.