bug#32812: 27.0.50; macOS Mojave GNU Emacs crash after 5-10 minutes or so

[Zack Piper]

(Final attempt at sending, TLS was being enforced for my outgoing 
emails, sorry Alan for the spam!)

Hi Alan,


On 24 Sep 2018, at 11:17, Alan Third wrote:

> On Sun, Sep 23, 2018 at 04:21:13PM +0100, Zack Piper wrote:
> > Hi!
> >
> > (Replacing my post in #31904 with this since they're separate 
> > issues(?))
>
> Sorry, I somehow missed that previous email.

No worries at all!


> > I've applied a slightly modified (i.e. updated) version of Alan's 
> > patch from
> > bug #31904
> > (attached) to fix an issue concerning the buffer and mode-line not 
> > being
> > rendered. The patch works great, everything is now rendered.
> >
> > Now I notice that after 5-10 minutes (or even before), Emacs crashes 
> > with
> > the below:
> >
> > ```
> > objc[82784]: Invalid or prematurely-freed autorelease pool 
> > 0x1030032e0.
> > ```
> >
> > This started occurring since upgrading to macOS Mojave, so possibly 
> > there's
> > a bug with Mojave or just some incompatibility, not really sure!
>
> It’s a bit strange looking, and autorelease pools are something of a
> mystery to me.
>
> I have a suspicion, though, that just creating a new autorelease pool
> may solve this. I’ve attached a patch. It’s for emacs-26, but 
> should
> apply OK to master, or without too much work anyway.

> It simply wraps the call to displayIfNeeded in a new pool:
>
> static void
> ns_flush_display (struct frame *f)
> /* Force the frame to redisplay.  If areas have previously been marked
>    dirty by setNeedsDisplayInRect (in ns_focus), then this will call
>    draw_rect: which will "expose" those areas.  */
> {
>   NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
>   [FRAME_NS_VIEW (f) displayIfNeeded];
>   [pool release];
> }

> Thanks for testing the patch and raising this issue. There’s not 
> been
> a lot of feedback so far and I think we’re going to have to commit 
> the
> patch soon given that Mojave is out today.

You're very welcome, and thanks for providing the additional patch!


(Later email):


> This patch doesn’t help, I finally reproduced the crash with it in
> place.

Oh, damn.

I truly wish I could help somewhat, if you need anything additional from 
me let me know.

I've never really meddled Objective C before, so I'd likely not be able 
to help much.

Obviously I'm more than happy to test any patches you throw at me! :-)

I did look at the autorelease pool thing and tried to see where it would 
fit in, to no avail.

Let me know if you need anything.



> --
> Alan Third

Thanks,
Zack