bug#28850: 26.0.90; Error running timer 'jit-lock-stealth-fontify': (error "Invalid search bound (wrong side of point)")

[Alan Mackenzie]

Hello, Eli.

On Mon, May 06, 2019 at 18:35:28 +0300, Eli Zaretskii wrote:
> > Date: Sun, 5 May 2019 09:06:22 +0000
> > Cc: contovob@tcd.ie, 28850@debbugs.gnu.org
> > From: Alan Mackenzie <acm@muc.de>

> > That's the theory.  The fix, which is now obvious, is to (setq
> > before-sws-pos ...) after moving back over a macro.  Perhaps I should
> > check the result of c-down-list-backward too, but that's to be done
> > after checking the current fix.

> > I can't actually test this myself, so would you please try out the patch
> > below in your test setup, and let me know whether it fixes this nasty
> > bug.

> With this patch, the problem is gone, so I guess you hit the nail on
> the head.  Thanks.

Thank you!  I've committed that patch.

> (In terms of testing, I think you can visit textprop.c, then turn on
> jit-lock-stealth, and let Emacs run for a while.  Without the patch,
> you should see the error message pretty soon.)

Are you sure you mean textprop.c?  With jit-lock-stealth-mode enabled, I
couldn't get the error on textprop.c.  That file only has seven CPP
constructs, all right near the start of the buffer, and none of them
seem to have the closing brace/bracket/parenthesis in the right place to
trigger the error.

Anyway, it's probably not that important.  There was definitely a bug in
CC Mode at that place in c-beginning-of-statement-1, and there was
definitely a bug in CC Mode which threw an exception in your stealthy
fontification.  The patch appears to have fixed both.

I'll close bug #28850 (again), seeing as how Basil C. has confirmed that
"his" bug is fixed, too.

-- 
Alan Mackenzie (Nuremberg, Germany).