Lars Ingebrigtsen <larsi@gnus.org> writes:

> awrhygty@outlook.com writes:
>
>> Evaluate the form below and type 'C-p' or 'C-n' repeatedly to display
>> python eldoc messages.
>> After 20-30 key input, an error occurs.
>> Then look at the *shell* buffer, some numbers in output lines are
>> absent.
>> If setting debug-on-error to 't, *Backtrace* buffer popups,
>
> That sounds familiar -- I think I recall something like this being fixed
> in eldoc...
>
> Yes, I can reproduce this problem in Emacs 27.2, but not in Emacs 29.
> So I guess this has been fixed by now, and I'm closing this bug report.

Not quite yet. I found a more reliable reproducer for Emacs 29, which
could reproduce the bug on my machine with emacs -q.

(progn
  (setq debug-on-error t)
  (shell)
  (insert " i=0; while sleep 0.05; do i=$((i + 1)); echo $i; done")
  (comint-send-input)
  (run-python)
  (switch-to-buffer (generate-new-buffer "tmp"))
  (insert "len\nstr")
  (python-mode))

If it doesn't work bug immediately, try lowering the "0.05" number.

Please consider applying the following patch to fix this.