GNU bug report logs - #70311
Crash when dnd-indicate-insertion-point is non-nil

Previous Next

Full log

Message #14 received at 70311 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Po Lu <luangruo <at> yahoo.com>
Cc: 70311 <at> debbugs.gnu.org, gregsexton <at> gmail.com
Subject: Re: bug#70311: Crash when dnd-indicate-insertion-point is non-nil
Date: Sat, 13 Apr 2024 15:06:41 +0300

> From: Po Lu <luangruo <at> yahoo.com>
> Cc: Greg Sexton <gregsexton <at> gmail.com>,  70311 <at> debbugs.gnu.org
> Date: Sat, 13 Apr 2024 19:58:25 +0800
> 
> Eli Zaretskii <eliz <at> gnu.org> writes:
> 
> >> From: Greg Sexton <gregsexton <at> gmail.com>
> >> 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.
> >
> > Po Lu, any comments or suggestions?
> 
> As regards suggestions, none at present.  It's not clear to me why
> waiting_for_input should continue to exist, but neither am I especially
> satisfied with the present arrangements for calling drag-and-drop
> callbacks in nsterm.m: some means should be devised of returning to the
> event loop during a DND session, rather than calling Lisp and parts of
> redisplay from non-reentrant input handlers that the toolkit can call at
> will.
> 
> Come to think of it, at the time this kludge was written, I never quite
> understood why DND events were never received on Mac OS, when the same
> was smooth sailing on GNUstep.

So you think the suggested bad-aid is the best we can currently do to
prevent crashes in those cases?

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.