bug#70707: 30.0.50; [PATCH] ; Check the process param in function (python-shell-completion-at-point)

[Lin Sun <sunlin7.mail@gmail.com>]

> Hi,
>
> There is an unexpected error message happening with function
> `python-shell-completion-at-point`.
> > Wrong type argument: processp, nil
> It happened because the function does NOT check the process param.
> The patch will check the param and display a user error message gracefully.
>
> Steps to reproduce the issue.
> 1. $ emacs -q /tmp/a.py # start emacs and open a python source file
> 2. type "C-c C-p" (or M-x run-python) to start a python shell
> 3. type exit() to stop the python process but the buffer still exists
> 4. Switch to *python* buffer, then M-x
> python-shell-completion-at-point  will get the error message
>
> Please help review the patch. Thanks. Regards
>
>
> From aa44c95c7f13f2d68be83260e618cf4d806b313b Mon Sep 17 00:00:00 2001
> From: Lin Sun <sunlin7@hotmail.com>
> Date: Wed, 1 May 2024 06:55:31 +0000
> Subject: [PATCH] ; Check the process param in function
>  (python-shell-completion-at-point)
>
> * lisp/progmodes/python.el (python-shell-completion-at-point):
>   Check the process param at the beginning of the function.
> ---
>  lisp/progmodes/python.el | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
> index d6c29e5ffc..4b2e2f8215 100644
> --- a/lisp/progmodes/python.el
> +++ b/lisp/progmodes/python.el
> @@ -4708,6 +4708,8 @@ python-shell-completion-at-point
>  Optional argument PROCESS forces completions to be retrieved
>  using that one instead of current buffer's process."
>    (setq process (or process (get-buffer-process (current-buffer))))
> +  (unless process
> +    (user-error "No active python inferior process"))
>    (let* ((is-shell-buffer (derived-mode-p 'inferior-python-mode))
>           (line-start (if is-shell-buffer
>                           ;; Working on a shell buffer: use prompt end.
> --
> 2.20.5

Hi Kobarity, Please help review the patch for checking process and
emitting user-error when it's not available. Thanks.