Hi!

I did some simple measurements with and without this patch. I ran
`(file-name-all-completions "x" "src")' on the Emacs src directory. The
timing values were almost identical (varying between 0.001012 and 0.001080).

The way I see it, the patch doesn't do any harm in any coding system, and
it is fast. Hence, I don't really see that it's worth the effort to make
this code conditional.

However, please write a patch for this if you still thinks it's necessary.
I can test it here to make sure it works under OS X.

    -- Anders


On Mon, Dec 21, 2015 at 4:39 AM, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Sun, 20 Dec 2015 23:00:40 +0100
> > From: Anders Lindgren <andlind@gmail.com>
> > Cc: random832@fastmail.com, 22169@debbugs.gnu.org
> >
> > I managed to get the attached patch to work (when used in conjunction
> with my
> > previous patch).
> >
> > I've tested:
> >
> > * C-x C-f a TAB
> > * (find-file-all-competions "a" ".")
>
> OK, thanks.
>
> The next step is arrange for this to happen only with those values of
> file-name-coding-system that require it.  My idea is to put a special
> property on the coding-system's symbol, and check that inside
> file_name_completion (outside of the loop).  Can you add this, or do
> you want me to suggest a patch along these lines for you to test?
> Note that the property check will have to be done on
> file-name-coding-system if it is non-nil, otherwise on
> default-file-name-coding-system (if that is non-nil).
>
> Thanks.
>