bug#70966: 30.0.50; eshell/diff produces track-changes errors

[Eli Zaretskii]

> Date: Wed, 15 May 2024 11:05:02 -0700
> From:  Steven Allen via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> 
> Steps to reproduce:
> 
> 1. Start `emacs -Q`.
> 2. Open `M-x eshell RET`.
> 3. Run `diff a b` (calls `eshell/diff`). The files `a` and `b` don't
> have to exist.
> 
> This results in warnings buffer complaining about:
> 
>     Warning (emacs): Missing/incorrect calls to 
> ‘before/after-change-functions’!!
> 
> Where the logged `track-changes--error-log` is:
> 
>     (("*Diff*"
>       ((t track-changes--recover-from-error nil nil)
>        (t track-changes-fetch
>           (#1=
>            #s(track-changes--tracker :signal diff--track-changes-signal
>                                :state
>                                #s(track-changes--state :beg 174 :end
>                                                        1 :before nil
>                                                        :next nil)
>                                :nobefore t :immediate nil)
>            diff--track-changes-function)
>           nil)
>        (t diff--track-changes-signal (#1#) nil)
>        (t track-changes--call-signal (#<buffer *Diff*> #1#) nil)
>        (t apply (track-changes--call-signal #2=(#<buffer *Diff*> #1#)) nil)
>        (t timer-event-handler
>           ([t 26180 63752 401543 nil track-changes--call-signal #2# nil
>         112000 nil])
>           nil))
>       [return (nil . minibuffer-complete-and-exit) 100
>         (nil . self-insert-command) 105 (nil . self-insert-command)
>         102 (nil . self-insert-command) 102
>         (nil . self-insert-command) 32 (nil . self-insert-command)
>         97 (nil . self-insert-command) 32
>         (nil . self-insert-command) 98 (nil . self-insert-command)
>         return (nil . eshell-send-input)]))

Thanks, I'm adding Stefan to this discussion.