Subject: bug#73777: set-fontset-font doesn't set :size for specific characters when using some fonts

From: Eli Zaretskii <[email-masked]>
Date: Fri, 18 Oct 2024 09:27:36 +0300

> From: Rodrigo Morales <[email-masked]>
> Date: Sat, 12 Oct 2024 14:10:25 -0500
> 
> 
> I am using GNU Emacs 29.4 in Ubuntu 22.04.5 LTS.
> 
> Today, I was trying to change the font size for the character =“= (#x201C, LEFT DOUBLE QUOTATION MARK) using the sexp shown below. I noticed an inconsistency: that sexp only sets the size for the character =“= when specific fonts are used.
> 
> #+BEGIN_SRC elisp
> (set-fontset-font t ?“ (font-spec :family "Noto Sans Mono" :size 50))
> #+END_SRC

Before I start digging into how we handle :size in a fontset, I have
two questions:

 . did you reset use-default-font-for-symbols to nil? without that,
   Emacs prefers to use the default face's font for punctuation and
   symbols, effectively disregarding the fontsets
 . which fonts did you find problematic in this case? you say
   "specific fonts", but it is not clear which fonts exhibit this
   behavior

Thanks.