Subject: Re: bug#71466: 30.0.50; Buffer-menu-group-by non-nil resets point when Buffer List is reverted

From: Dmitry Gutov <[email-masked]>
Date: Tue, 18 Jun 2024 01:24:26 +0300

On 17/06/2024 18:43, Eshel Yaron wrote:
> Dmitry Gutov <[email-masked]> writes:
> 
>> On 17/06/2024 10:40, Eshel Yaron wrote:
>>>>> But this will not handle modes that don't use tabulated-list.
>>>>> For example, reverting an xref buffer with outlines now restores
>>>>> visibility of outlines, but doesn't restore point.  OTOH, maybe it's
>>>>> not responsibility of outline-minor-mode to restore point when it's
>>>>> not on a heading line.
>>>> For xref I propose a separate patch that keeps point on the same line
>>>> after reverting the xref buffer:
>>> LGTM, but FWIW the situation with xref-revert-buffer is not ideal IMO:
>>> it might be cleaner to leave 'g' bound to the usual revert-buffer and
>>> set revert-buffer-function to (a slightly modified) xref-revert-buffer.
>>> That way xref-revert-buffer wouldn't need to duplicate generic parts of
>>> revert-buffer, such as running revert-buffer-restore-functions.  WDYT?
>>
>> I'm okay with that.
> 
> Here's a concrete proposal:

Thanks, works for me, with some caveats.

> diff --git a/lisp/progmodes/xref.el b/lisp/progmodes/xref.el
> index fb6c9dad73b..9878806c0de 100644
> --- a/lisp/progmodes/xref.el
> +++ b/lisp/progmodes/xref.el
> @@ -993,7 +993,6 @@ xref--xref-buffer-mode-map
>       ;; suggested by Johan Claesson "to further reduce finger movement":
>       (define-key map (kbd ".") #'xref-next-line)
>       (define-key map (kbd ",") #'xref-prev-line)
> -    (define-key map (kbd "g") #'xref-revert-buffer)
>       (define-key map (kbd "M-,") #'xref-quit-and-pop-marker-stack)
>       map))
>   
> @@ -1011,6 +1010,7 @@ xref--xref-buffer-mode
>           #'xref--imenu-extract-index-name)
>     (setq-local add-log-current-defun-function
>                 #'xref--add-log-current-defun)
> +  (setq-local revert-buffer-function #'xref-revert-buffer)
>     (setq-local outline-minor-mode-cycle t)
>     (setq-local outline-minor-mode-use-buttons 'insert)
>     (setq-local outline-search-function
> @@ -1273,22 +1273,17 @@ xref--show-common-initialize
>             xref--original-window-intent (assoc-default 'display-action alist))
>       (setq xref--fetcher fetcher)))
>   
> -(defun xref-revert-buffer ()
> +(defun xref-revert-buffer (&rest _)     ; Ignore `revert-buffer' args.
>     "Refresh the search results in the current buffer."
>     (interactive)

It seems like the interactive use of 'xref-revert-buffer' would suffer 
with this change (it wouldn't call the restore functions). And it might 
be used where people rebind it to a different key in their configs.

Perhaps instead xref-revert-buffer should become an obsolete alias to 
'revert-buffer'. And the current definition would be renamed to 
xref--revert-buffer (which we'll set revert-buffer-function to).