bug#57563: 28.1; macOS - layout warning at startup

[Bob Kline <bkline@rksystems.com>]

On Fri, Sep 16, 2022 at 1:56 AM Gerd Möllmann <gerd.moellmann@gmail.com> wrote:
>
> Bob Kline <bkline@rksystems.com> writes:
> ...
> > https://github.com/caldwell/build-emacs/issues/123
>
> Thanks for the info, Bob.

I got a quick response from the maintainer of the build scripts which
feed into emacsformacosx.com (which is where homebrew gets its
pre-built packages). He showed me how to figure out which Emacs
executable the launcher will choose and how to run that executable
directly, bypassing the launcher. I did so, and the bug still kicked
in. So as my mental picture of what's going on slowly comes into
better focus, what I think I'm seeing now is:

* the build script creates three binaries:
  - one for arm64 macOS 11
  - one for x86_64 macOS 10.11
  - one for x86_64 macOS 10.14
* the launcher narrows the candidates to those matching the computer's
architecture
* the launcher eliminates candidates built for a newer OS version than
the computer's
* the launcher chooses and runs the candidate built for the most
recent OS version
* when I run that Emacs (x86_64 macOS 10.14) on my x86_64 macOS 12 I see the bug
* when I run the build script on this machine I get Emacs built for
x86_64 macOS 12
* when I execute that Emacs on this machine I don't see the bug

So the launcher does not appear to be involved with the bug after all.
MacOS 12 appears to be happy running an Emacs (any version) built on
macOS 12, but unhappy running Emacs built on macOS 10.14. It seems
plausible that the reason the bug doesn't surface on arm64 is that
macOS 12 has no problems with an Emacs built on macOS 11, and the
launcher can find a macOS 11 Emacs for arm64 but not for x86_64. I
tried to set up a machine with macOS 10.14 or macOS 11 to see if the
bug showed up there, but it seems that Apple doesn't want users
installing older versions of macOS on their computers (Apple has
instructions [1] for downloading installers for those versions, but
when you follow the links you are taken to the Apple store where you
can click "Get" and watch the download progress to the end followed by
an error message saying that the installer was launched and failed,
and instead of dropping the launcher into the file system so you can
put it on some removable media the download is nowhere to be found, as
far as I could see).

I'll leave it up to you whether or not the bug should be reopened. As
noted in an earlier comment, we do have the requested stack trace [2].
I'm perfectly willing to supply any other information I can provide,
or attempt any further experiments, but I do have an Emacs without the
bug, so I'm happy (or as happy as I'll be with an unsolved mystery).
😂

[1] https://support.apple.com/en-gb/HT211683
[2] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=53481#5