bug#45658: Infinite loop in run loop on macOS

[Jimmy Yuen Ho Wong]

The breakpoint at 4733 does get reached, there's no beach ball for
this initially, just an unresponsive frame. I can't Cmd-TAB to it, I
have to use the mouse to select it in Mission Control. The windows
sometimes freeze, sometimes go blank then freeze. This bug can
occasionally be produced by issuing `EDITOR=emacsclient git rebase -i
HEAD~2` in the terminal, but not consistently.

I'm on Catalina, not on Homebrew, I just checked out the emacs repo
and switched to the emacs 27 branch. I'm on the latest commit.

> Does 'emacs -q' also freeze up

I don't have a way to reproduce this bug consistently so I don't know.

Jimmy

On Sun, Jan 10, 2021 at 12:01 AM Alan Third <alan@idiocy.org> wrote:
>
> On Sat, Jan 09, 2021 at 11:21:48PM +0000, Jimmy Yuen Ho Wong wrote:
> > Ok I've just reproduced this again, this time simply by opening a file
> > in the terminal with emacsclient, in the hope Emacs.app will open it.
> > I've switched to the thread running fd_handler (nsterm.m:6100:20
> > right?) This is the frame variables:
>
> That all looks pretty much like I'd expect.
>
> Can you check if it ever reaches the end of ns_select? You could
> either stick a breakpoint at, say, like 4733 of nsterm.m, or make it
> print to the console or whatever.
>
> I suspect that since you're seeing a spinning wheel it's not reaching
> the end, but we may as well find out for sure.
>
> You're running macOS 10.15, yes?
>
> Do you use Homebrew or something else?
>
> Does 'emacs -q' also freeze up?
> --
> Alan Third