bug#31376: 26.0.50; print-charset-text-property not honored

[Eli Zaretskii]

> From: Noam Postavsky <npostavs@gmail.com>
> Cc: handa@gnu.org,  31376@debbugs.gnu.org,  schwab@linux-m68k.org,  
> eller.helmut@gmail.com
> Date: Mon, 14 May 2018 19:15:30 -0400
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > This seems to rely on some relationship between what char-charset
> > returns and the car of charset-list, is that right?
> 
> The idea is to take the first if it's not eq to what char-charset
> returns, or the second otherwise (on the assumption that it's different
> from the first).  Perhaps clearer if I use cl-find:
> 
>     (defun print-tests--prints-with-charset-p (ch odd-charset)
>       "Return t if `prin1-to-string' prints CH with the `charset' property.
>     CH is propertized with a `charset' value according to
>     ODD-CHARSET: if nil, then use the one returned by `char-charset',
>     otherwise, use a different charset."
>       (integerp
>        (string-match
>         "charset"
>         (prin1-to-string
>          (propertize (string ch)
>                      'charset
>                      (if odd-charset
>                          (cl-find (char-charset ch) charset-list :test-not 
> #'eq)
>                        (char-charset ch)))))))

Maybe I'm missing something, but the negation of the test seemed to be
missing from the original code.  But it was a hard day, so maybe my
mind is foggy...

Thanks.