bug#24162: 25.0.50; utf8 filenames with ornamented characters in MS-Windows

[Eli Zaretskii <eliz@gnu.org>]

> From: "cschr" <cschr@freenet.de>
> Date: Fri, 5 Aug 2016 10:38:52 +0200
> 
> when trying to process existing file "täst.txt", an empty new file with name t\344st.txt will be created
> unexpectedly in the following cases:
> 
> 1. when executing the following ms-windows command line:
> 
> C:\Programme\Emacs-24.5-Win64\bin\emacsclientw.exe -n -a
> C:\Programme\Emacs-24.5-Win64\bin\runemacs.exe -c "täst.txt"
> 
> 2. when typing "T" (modify timestamp) in emacs dired on file "täst.txt"

For the 2nd issue, there was a subtle bug in dired-aux.el, now fixed
on the master branch, which could sometimes mis-encode the file names
passed on the 'touch' command line.  However, the bug raises its ugly
head when the locale-coding-system cannot encode the file names passed
to 'touch', so given the data of your system locale:

  value of $LANG: DES
  locale-coding-system: cp1252

I very much doubt that bug affected you, because codepage 1252 can
very well encode the character in question, ä.

So I'm inclined to guess that the problem is in the version of
touch.exe you have installed: is it by any chance a Cygwin or MSYS
build of the GNU 'touch' utility?  If it is, then it assumes the file
names will be encoded in UTF-8, while the native Windows build of
Emacs will encode them in codepage 1252.

For the 1st issue, I cannot reproduce it on my system.  I replaced the
ä character with a character supported by my system codepage, and
could successfully invoke Emacs via emacsclientw.  So once again, my
guess would be that your system locale is somehow misconfigured, or
maybe you are invoking Emacs from some MSYS2 shell that expects file
names to be encoded differently.  Or maybe it's one of your
customizations: did you try the same recipe in "emacs -Q"?

Btw, what is the -c switch to runemacs you used?  When I try it, Emacs
complains that -c is an unknown switch.

Thanks.