On 3/8/2013 12:53 PM, Eli Zaretskii wrote:
>> Date: Fri, 08 Mar 2013 22:33:07 +0200
>> From: Eli Zaretskii <eliz@gnu.org>
>> Cc: 13907@debbugs.gnu.org
>>
>> And one more question: what is the value of file-name _before_ it is
>> passed to cygwin-convert-file-name-from-windows?  Does it perhaps
>> already have the U-umlaut replaced by a blank?
> 
> I think the problem is on the C level, not on the Lisp level.  Take a
> look at w32term.c:construct_drag_n_drop -- it uses ANSI version of
> DragQueryFile to get the file name, then decodes it by DECODE_FILE.
> But DECODE_FILE uses UTF-8 in the cygw32 build, so this is
> inappropriate for decoding file names that come from Windows APIs.
> 
> Instead, in the cygw32 build, construct_drag_n_drop should use
> DragQueryFileW and convert the file name to the internal Emacs
> representation using from_unicode.
> 


Thanks for finding that! I've been swamped this week, and I haven't been able to
do any investigation. I'll see whether I can come up with a fix this weekend.