Failure during the print of select.select output with unblocking sys.stdin

[yurivict]

Bug report

Bug description:

This code terminates with error messages after several loop iterations:

import sys
import os
import select

os.set_blocking(sys.stdin.fileno(), False)

while True:
    print('>')
    ready = select.select([sys.stdin, ], [], [], 0.0)[0]
    print(f'< ready={ready}')

$ python3.11 stdin-nonblocking-bug-report.py
<... skip many iterations ...>
< ready=[]
>
< ready=[]
>
< ready=[]
Traceback (most recent call last):
Exception ignored in: <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'>
Exception ignored in sys.unraisablehook: <built-in function unraisablehook>

$ echo $?
120

The failure occurs in print(f'< ready={ready}').

Python-3.11
FreeBSD 14.1

CPython versions tested on:

3.11

Operating systems tested on:

Other

[Zheaoli]

Can not reproduce it on main and 3.13 branch. Would you mind providing more detail?

[yurivict]

@Zheaoli
Did you run on FreeBSD ?
What other details can I provide?

[Zheaoli]

Did you run on FreeBSD ?

Yes,

root@freebase-test:~ # fastfetch
```                        `        root@freebase-test
  ` `.....---.......--.```   -/     ------------------
  +o   .--`         /y:`      +.    Host: Standard PC (i440FX + PIIX, 1996) (pc-i440fx-9.0)
   yo`:.            :o      `+-     Kernel: FreeBSD 14.1-RELEASE
    y/               -/`   -o/      Uptime: 19 mins
   .-                  ::/sy+:.     Shell: sh
   /                     `--  /     Terminal: /dev/pts/0
  `:                          :`    CPU: QEMU Virtual version 2.5+ (8) @ 2.50 GHz
  `:                          :`    GPU: Unknown Device 1111 (VGA compatible)
   /                          /     Memory: 4.14 GiB / 47.96 GiB (9%)
   .-                        -.     Swap: 0 B / 1.00 GiB (0%)
    --                      -.      Disk (/): 4.31 GiB / 101.24 GiB (4%) - zfs
     `:`                  `:`       Local IP (eth0): 192.168.12.41/16
       .--             `--.         Locale: en_US.UTF-8
          .---.....----.

[yurivict]

I encountered this problem with the python311 package, and you said that you tried 3.13

Can you try with python311?
Maybe it is already fixed in 3.13

[ericvsmith]

3.11 is no longer receiving bug fixes. Can you try 3.12 or 3.13? See https://devguide.python.org/versions/