bug#31138: Native json slower than json.el

[Eli Zaretskii]

> Cc: p.stephani2@gmail.com, sebastien@chapu.is, yyoncho@gmail.com,
>  31138@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Tue, 23 Apr 2019 01:23:44 +0300
> 
> On 22.04.2019 20:26, Eli Zaretskii wrote:
> > I don't think we should abort, we don't do that anywhere else.
> 
> The key word here is "validation". If certain folks in this discussion 
> are right, libjansson always returns valid utf-8 encoded strings, or 
> intends to.
> 
> So if we implement fast validation for multibyte strings as well, the 
> "else" branch should never be taken, and it would make sense to abort in 
> that case. Not necessarily abort as in "exit Emacs", but maybe signal an 
> error. The libjansson developers might in the end be thankful for bug 
> reports.

The interests of libjansson developers aside, I disagree that
low-level text decoding functionality should signal an error, let
alone abort.  It is up to the application to decide whether having raw
bytes in strings is legit or not.  This is our policy everywhere,
including when UTF-8 is the standard encoding, so I don't think this
case is special in any way.