bug#70311: closed (Crash when dnd-indicate-insertion-point is non-nil)

[GNU bug Tracking System]

Your message dated Sun, 14 Apr 2024 13:17:37 +0300
with message-id <86wmp0meny.fsf@gnu.org>
and subject line Re: bug#70311: Crash when dnd-indicate-insertion-point is 
non-nil
has caused the debbugs.gnu.org bug report #70311,
regarding Crash when dnd-indicate-insertion-point is non-nil
to be marked as done.

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70311: https://debbugs.gnu.org/cgi/bugreport.cgi?bug=70311
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> --- Begin Message ---
>
>
>
> Subject: 
>
> Crash when dnd-indicate-insertion-point is non-nil
>
>
>
>
> Date: 
>
> Tue, 9 Apr 2024 11:26:41 +0100
>
>
>
>
> Emacs (29.1.90) can crash on Mac OS X when dnd-indicate-insertion-point
> is non-nil.
>
> I'm not able to deterministically reproduce this, but I have a high
> success rate dragging a file over the window and just randomly moving
> it around without releasing the click.
>
> This said, I attached a debugger and found the root cause.
>
> There is code that looks like this in dnd-handle-movement:
>
>   (when dnd-indicate-insertion-point
>      (ignore-errors
>        (goto-char (posn-point posn))))
>
> posn-point can return nil, which causes goto-char to call
> wrong_type_argument, this reaches signal_or_quit (eval.c), which calls
> emacs_abort as waiting_for_input is true.
>
> A quick fix might be to when-let the result of posn-point, but I'm
> unsure if waiting_for_input being true points to a deeper issue.
>
> --
>
> Greg
>
>
>
> --- End Message ---
> --- Begin Message ---
>
>
>
> Subject: 
>
> Re: bug#70311: Crash when dnd-indicate-insertion-point is non-nil
>
>
>
>
> Date: 
>
> Sun, 14 Apr 2024 13:17:37 +0300
>
>
>
>
> > From: Po Lu <luangruo@yahoo.com>
> > Cc: gregsexton@gmail.com,  70311@debbugs.gnu.org
> > Date: Sun, 14 Apr 2024 17:24:12 +0800
> > 
> > Eli Zaretskii <eliz@gnu.org> writes:
> > 
> > >> From: Po Lu <luangruo@yahoo.com>
> > >> Cc: gregsexton@gmail.com,  70311@debbugs.gnu.org
> > >> Date: Sat, 13 Apr 2024 20:28:14 +0800
> > >> 
> > >> Eli Zaretskii <eliz@gnu.org> writes:
> > >> 
> > >> > So you think the suggested band-aid is the best we can currently do to
> > >> > prevent crashes in those cases?
> > >> 
> > >> Yes, unfortunately.
> > >
> > > Does the band-aid below look OK to you?
> > >
> > > diff --git a/lisp/dnd.el b/lisp/dnd.el
> > > index 89652d3..de1c58a 100644
> > > --- a/lisp/dnd.el
> > > +++ b/lisp/dnd.el
> > > @@ -149,8 +149,13 @@ dnd-handle-movement
> > >                  (with-selected-window window
> > >                    (scroll-down 1))))))))
> > >        (when dnd-indicate-insertion-point
> > > -        (ignore-errors
> > > -          (goto-char (posn-point posn)))))))
> > > +        (let ((pos (posn-point posn)))
> > > +          ;; We avoid errors here, since on some systems this runs
> > > +          ;; when waiting_for_input is non-zero, and that aborts on
> > > +          ;; error.
> > > +          (if (and pos (<= (point-min) pos (point-max)))
> > > +              (goto-char pos)
> > > +            pos))))))
> > 
> > Yes, please install.  Thanks.
>
> Thanks, installed on the emacs-29 branch, and closing the bug.
>
>
> --- End Message ---