Re: [PATCH v2] diff: run arguments through precompose_argv

> When running diff commands, a pathspec containing decomposed
> unicode code points is not converted to precomposed unicode form
> under Mac OS X, but we normalize the paths in the index and the
> history to precomposed form on that platform.  As a result, the
> pathspec would not match and no diff is shown.
>
> Unlike many builtin commands, the "diff" family of commands do
> not use parse_options(), which is how other builtin commands
> indirectly call precompose_argv() to normalize argv[] into
> precomposed form on Mac OSX.  Teach these commands to call
> precompose_argv() themselves.
>
> Note that precomopose_argv() normalizes not just paths but all
> command line arguments, so things like "git diff -G $string"
> when $string has the decomposed form would first normalized into
> the precomposed form and would stop hitting the same string in
> the decomposed form in the diff output with this change.  It is
> not a problem per-se, as "log" family of commands already use
> parse_options() and call precompose_argv()--we can think of it
> as making the "diff" family of commands behave in a similar way
> as the commands in the "log" family.
>
> Signed-off-by: Alexander Rinass <alex@fournova.com>
> Helped-by: Torsten Bögershausen <tboegi@web.de>
> Helped-by: Junio C Hamano <gitster@pobox.com>