bug#20608: 25.0.50; vc-git-log-view-mode inserts "Show 2X entries" at bob when interrupted

[Stefan Monnier]

> It seems like a general problem, to be fixed either in vc-do-command (by
> unsetting the process sentinel before deleting the process), or in
> vc--process-sentinel. Here's the patch for the second option:

Indeed, it's a general problem.  Maybe handling it in vc-do-command
would be a good idea, but unsetting the process sentinel altogether
sounds a bit dangerous (the sentinel might also be used to clear the
":running" annotation in the modeline and other such things).


        Stefan


> diff --git a/lisp/vc/vc-dispatcher.el b/lisp/vc/vc-dispatcher.el
> index a2c1cba..d6b50b7 100644
> --- a/lisp/vc/vc-dispatcher.el
> +++ b/lisp/vc/vc-dispatcher.el
> @@ -183,35 +183,36 @@ Another is that undo information is not kept."
>  (defvar vc-sentinel-movepoint)          ;Dynamically scoped.
 
>  (defun vc--process-sentinel (p code)
> -  (let ((buf (process-buffer p)))
> +  (let ((buf (process-buffer p))
> +        (status (process-status p)))
>      ;; Impatient users sometime kill "slow" buffers; check liveness
>      ;; to avoid "error in process sentinel: Selecting deleted buffer".
>      (when (buffer-live-p buf)
>        (with-current-buffer buf
>          (setq mode-line-process
> -              (let ((status (process-status p)))
> -                ;; Leave mode-line uncluttered, normally.
> -                (unless (eq 'exit status)
> -                  (format " (%s)" status))))
> -        (let (vc-sentinel-movepoint
> -              (m (process-mark p)))
> -          ;; Normally, we want async code such as sentinels to not move 
> point.
> -          (save-excursion
> -            (goto-char m)
> -            ;; Each sentinel may move point and the next one should be run
> -            ;; at that new point.  We could get the same result by having
> -            ;; each sentinel read&set process-mark, but since `cmd' needs
> -            ;; to work both for async and sync processes, this would be
> -            ;; difficult to achieve.
> -            (vc-exec-after code)
> -            (move-marker m (point)))
> -          ;; But sometimes the sentinels really want to move point.
> -          (when vc-sentinel-movepoint
> -         (let ((win (get-buffer-window (current-buffer) 0)))
> -           (if (not win)
> -               (goto-char vc-sentinel-movepoint)
> -             (with-selected-window win
> -               (goto-char vc-sentinel-movepoint))))))))))
> +              ;; Leave mode-line uncluttered, normally.
> +              (unless (eq 'exit status)
> +                (format " (%s)" status)))
> +        (unless (eq 'signal status)
> +          (let (vc-sentinel-movepoint
> +                (m (process-mark p)))
> +            ;; Normally, we want async code such as sentinels to not move 
> point.
> +            (save-excursion
> +              (goto-char m)
> +              ;; Each sentinel may move point and the next one should be run
> +              ;; at that new point.  We could get the same result by having
> +              ;; each sentinel read&set process-mark, but since `cmd' needs
> +              ;; to work both for async and sync processes, this would be
> +              ;; difficult to achieve.
> +              (vc-exec-after code)
> +              (move-marker m (point)))
> +            ;; But sometimes the sentinels really want to move point.
> +            (when vc-sentinel-movepoint
> +              (let ((win (get-buffer-window (current-buffer) 0)))
> +                (if (not win)
> +                    (goto-char vc-sentinel-movepoint)
> +                  (with-selected-window win
> +                    (goto-char vc-sentinel-movepoint)))))))))))
 
>  (defun vc-set-mode-line-busy-indicator ()
>    (setq mode-line-process