bug#72532: [PATCH] ; lisp/progmodes/which-func.el (which-function-mode): check buffer

[Stefan Kangas <stefankangas@gmail.com>]

Raffael Stocker <r.stocker@mnet-mail.de> writes:

> From cd8b170f2c716cf67623c4ffc4ae38dc63c49496 Mon Sep 17 00:00:00 2001
> From: Raffael Stocker <r.stocker@mnet-mail.de>
> Date: Thu, 8 Aug 2024 21:38:14 +0200
> Subject: [PATCH] ; lisp/progmodes/which-func.el (which-function-mode): check
>  buffer
>
> Ensure we are not selecting a deleted buffer.
> ---
>  lisp/progmodes/which-func.el | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/lisp/progmodes/which-func.el b/lisp/progmodes/which-func.el
> index 28aacd335ba..5326be5e877 100644
> --- a/lisp/progmodes/which-func.el
> +++ b/lisp/progmodes/which-func.el
> @@ -309,9 +309,10 @@ which-function-mode
>      (setq which-func-update-timer
>            (run-with-idle-timer which-func-update-delay t #'which-func-update)))
>    (dolist (buf (buffer-list))
> -    (with-current-buffer buf
> -      (which-func--header-line-remove)
> -      (which-func-ff-hook))))
> +    (when (buffer-live-p buf)
> +      (with-current-buffer buf
> +        (which-func--header-line-remove)
> +        (which-func-ff-hook)))))

`buffer-list' is documented to return a list of all live buffers, so it
would be good to understand why buffers are getting killed in this loop.

In other words, are we sure that your patch is not just covering up some
problem elsewhere?

>
>  (defvar which-function-imenu-failed nil
>    "Locally t in a buffer if `imenu--make-index-alist' found nothing there.")
> --
> 2.46.0