Subject: bug#30788: 27.0.50; Getting 'char-displayable-p: Invalid hash table rehash size: 1.0' when starting emacs -Q

From: Ulrich Mueller <[email-masked]>
Date: Wed, 14 Mar 2018 22:19:45 +0100

>>>>> On Wed, 14 Mar 2018, Eli Zaretskii wrote:

>> Note that it has also been fixed in the fontconfig git repository:
>> https://cgit.freedesktop.org/fontconfig/commit/?id=923b5be626a6e03fbaeee0b5cd6d0246c2f8f36f

> I've seen that.  Does it really fix the problem?  What happens if you
> run Emacs like so:

>   $ LC_ALL=C emacs -Q

> (If this works with the fixed version of fontconfig, then I guess I
> completely misunderstand the issue.)

Indeed, the commit in fontconfig doesn't entirely fix it. While the
above command works (regardless of any other LANG and LC_* settings),
the following combination still fails: 

   $ unset LANG LC_ALL
   $ LC_NUMERIC=de_DE.UTF-8 emacs -Q

> In any case, I think it's good for Emacs to be immune to buggy
> versions of fontconfig, especially since we already needed to clean up
> after similar problems in gtk_init.

I agree, especially when the fix comes at no cost.