bug#45541: 28.0.50; Frequent crashes on ARM macOS

[Philipp Stephani]

Am Mi., 30. Dez. 2020 um 21:35 Uhr schrieb Eli Zaretskii <eliz@gnu.org>:
>
> > From: Philipp Stephani <p.stephani2@gmail.com>
> > Date: Wed, 30 Dec 2020 15:42:24 +0100
> >
> > I'm now able to reproduce this consistently. It happens when a tooltip
> > appears and you hover over that tooltip
>
> How is that possible?  Tooltips are supposed to pop down as soon as
> you move the mouse.  Are those native NS tooltips, and if so, do they
> behave differently in this regard?

Yes, they don't vanish immediately when hovering over them.

>
> > The crash is in the line
> >   if (f && FRAME_NS_P (f))
> > in nsterm.m in ns_mouse_position, so apparently "f" is not NULL, but
> > also not valid.
>
> Maybe, if the tooltip popped down, we need to test whether f is a live
> frame?

We need to initialize "f" to NULL, because the loop that sets it
doesn't necessarily find a frame.