Re: frequent aborts in expose_overlaps

[Kim F. Storm]

Eric Hanchrow <address@hidden> writes:

> I am not sure exactly what I'm doing, but I think I'm switching
> between windows in my window manager, and attempting to bring the
> Emacs window to the "front" of the other windows.
>
> This is on recent Debian 'testing', with CVS emacs built from sources
> that I "cvs up"d today.
>
> Breakpoint 1, abort () at emacs.c:454
> 454       kill (getpid (), SIGABRT);
> (gdb) bt
> #0  abort () at emacs.c:454
> #1  0x080846a9 in expose_overlaps (...) at xdisp.c:21934

With assistance from Eric, I think I found the cause of the crash.
It happens when a header line has the "overlapping_p" flag set -- 
which triggers an xassert in expose_overlaps.

My fix is to exclude mode lines from the range passed to expose_overlaps
which seems most logical to me.

I have no way to test whether this has any unexpected effects, so if
you see some strange artifacts around the border between header lines
and the first text line when you expose a frame, tell me.

-- 
Kim F. Storm <address@hidden> http://www.cua.dk