bug#73022: 31.0.50; Crash in build_frame_matrix_from_leaf_window after C-x 2 and reducing terminal size

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 5 Sep 2024 10:18:35 +0200
> Cc: n142857@gmail.com, 73022@debbugs.gnu.org
> From: martin rudalics <rudalics@gmx.at>
> 
>  > Thanks, but could you tell how that change could have affected this
>  > assertion violation?
> 
> I attach the patch now, sorry for not doing it earlier.

You didn't attach it, but I think I understood what you wanted to
change, and did that by hand.

> IIUC we are talking about this assertion
> 
> 	  eassert (frame_size_change_delayed (XFRAME (w->frame))
> 		   || glyph_row_slice_p (window_row, frame_row));
> 
> Right?

Yes.

> If so, then this violation might be caused by the fact that we
> (1) did resize windows according to the new sizes but (2) did not update
> the frame sizes accordingly.

Can you elaborate on how this could be possible?  I always thought we
first allocate the frame matrices, and then the window matrices (by
suballocating them from the frame matrices).  Am I mistaken?

>  > AFAICT, adjust_frame_glyphs is not in the
>  > backtrace, so how could moving code inside of it affect what happens
>  > here?
> 
> I don't understand what you mean here.

Moving code in adjust_frame_glyphs could affect the assertion if the
assertion was being hit while adjust_frame_glyphs is still being
executed.  But that is not the case, so I don't understand how moving
some code in adjust_frame_glyphs without changing it could affect the
assertion violation.  I'm probably missing something.