Re: cygpath and star character

[Ken Brown <kbrown@cornell.edu>]

On 7/14/2021 4:10 AM, Tomas Jura via Cygwin wrote:
> Hi
> 
> I found a strange behaviour of the program cygpath program
> 
> 0 >cygpath -w "./*/*"           <--- IMHO wrong output
>   \
> 
> 0 >cygpath -w "./*/*"  | od -a                   <--- a detailed dump
> 0000000   o nul   *   \   o nul   *  nl
> 0000010

What you're seeing here is a consequence of the way Cygwin handles valid POSIX 
file names that contain characters (like '*') that are not allowed in Windows 
file names.  See "Forbidden characters in filenames" at

   https://cygwin.com/cygwin-ug-net/using-specialnames.html

Internally, Cygwin converts "./*/*" to the wide char string L"*\*" with '*' 
replaced by 0xf02a.  This then gets converted to the multibyte sequence in your 
"detailed dump", which is not quite detailed enough:

$ cygpath -w "./*/*"  | od -b
0000000 357 200 252 134 357 200 252 012
0000010

I tend to agree that this is not desirable behavior.  I doubt if users of 
'cygpath -w' expect to get a result that contains transformed forbidden 
characters.  But maybe there's a use case for this that I'm missing.  Corinna?

> 0 >cygpath -wp "./*/*"         <-- but this works as expected
> *\*
> 
> Is this bug or expected behavior ?

It looks to me like a bug that 'cygpath -w' and 'cygpath -wp' give different 
results on a path that doesn't contain a colon.

Ken