Gerd Möllmann <gerd.moellmann@gmail.com> writes:

>>> (make-frame '((window-system . x)))
>>>
>>> move to the graphical and back to the tty frame	I get a crash like
>>>
>>> #0  terminate_due_to_signal (sig=6, backtrace_limit=2147483647) at ../../src/emacs.c:432
>
> FWIW, I tried the equivalent with (window-system . ns) here, and
> couldn't provoke the assertion.

Using the right worktree helped.

Taking a closer look at tty_set_cursor, using the selected frame here
doesn't make sense to me. I don't see a good reason why the selected
frame has to have anything to do with where to place the cursor in an
updated frame. That looks more like a left-over from times before
multi-tty.

Could you please try the attached, Martin? The first one is what I think
it the fix. The second one is a cleanup that leads to more checks
without having GLYPH_DEBUG. If this also work for you, I'll put that in
master.

(I see a "flicker" of the tty frame after the make-frame. That is also
the case in Emacs 30.)