Re: Emacs 28: Specific TTF font gets loaded with font-backend x instead of ftcrhb

[Eli Zaretskii]

> From: Tassilo Horn <tsdh@gnu.org>
> Cc: help-gnu-emacs@gnu.org
> Date: Sat, 08 Feb 2020 10:52:13 +0100
> 
> Tassilo Horn <tsdh@gnu.org> writes:
> 
> > That's signalled in composite.c's Fcomposition_get_gstring function,
> > either line 1738 or 1749.  I've set beakpoints there, and now I have an
> > emacs instance halted at 1749.
> >
> > Thread 1 "emacs" hit Breakpoint 4, Fcomposition_get_gstring (
> >     from=<optimized out>, to=<optimized out>, 
> > font_object=XIL(0x5555562346e5), 
> >     string=XIL(0x555556a34ec4)) at composite.c:1749
> > 1749                error ("Attempt to shape unibyte text");
> 
> Oh, of course I've forgotten the most obvious part, i.e., frame 0:
> 
> (gdb) pp string
> "--"
> (gdb) pp font_object
> #<font-object "-JB  -JetBrains 
> Mono-normal-normal-normal-*-15-*-*-*-m-0-iso10646-1">
> 
> And indeed, the mode-line in a Gnus Summary buffer starts with "U:---".

We should not signal this error when the unibyte string is
pure-ASCII.  Let me think of a solution.