Re: [Emacs-diffs] emacs-26 9bf66c6: Don't run FOR_EACH_FRAME when there's no frame left (Bug#29961)

[martin rudalics]

> I recognized callers that either --enable-gcc-warnings complained
> about (because code after the FOR_EACH_FRAME loop clearly had
> undefined behavior unless the loop iterated at least once),

Which ones were these?  Neither next_frame nor prev_frame exhibit such
behavior IMO.

> and
> callers where historically there was an eassert that checked the
> assumption.

How far did you go back in history?

> check_glyph_memory doesn't fall into either category; and
> now that I look at its implementation it's clear that
> check_glyph_memory is not making the assumption.

Then you should have reverted that change too.  I've done that now.

Thanks, martin