bug#31316: Emacs hangs in `font_open_entity'

[Werner LEMBERG]

>> If I call `emacs -Q' and load the attached file `testchar' with
>> 
>>   C-x RET c gb18030 C-x C-f testchar
>> 
>> Emacs hangs in `font_open_entity' on my GNU/Linux box:
> 
> Does the patch below solve this without introducing any new
> problems?

Sort of, thanks.  After waiting a few seconds, Emacs now displays
three characters, but navigation is hard: it takes a few seconds to
move from character to character (I guess Emacs tries to reload the
missing glyph again and again).

>> Both `average_width' and `height' are always zero for `font'
>> regardless of `psize'; this effectively makes the above code an
>> endless loop.
> 
> What kind of strange font has both of these always zero?

If you tell me how to find out the name of the font Emacs tries to
use, I can try to answer this question.


    Werner