bug#12291: [rev 109796] wrong UTF-8 handling

[Eli Zaretskii]

> From: Kenichi Handa <handa@gnu.org>
> Cc: wl@gnu.org, 12291@debbugs.gnu.org, smithcu@gvsu.edu
> Date: Mon, 03 Sep 2012 09:59:22 +0900
> 
> > We can either read them as raw bytes, or convert them to u+FFFD.  The
> > former sounds like a more useful behavior to me, FWIW.
> 
> What to convert to U+FFFD?  Each byte, or the byte sequence?

The byte sequence.

> Anyway, we can't simply convert them to U+FFFD because it
> results in change of file contents just by reading and
> writing.

Yes, and that's why I prefer the raw-bytes way.

> I think converting each invalid byte to raw-byte is simpler
> and equally useful.

It's more useful, I think.