Re: nd/magic-pathspec exposes breakage in git-add--interactive on Windows

> With nd/magic-pathspec I get the following failure on Windows in
> t2016-checkout-patch.sh:
>
> expecting success:
>         set_state dir/foo work head &&
>         # the third n is to get out in case it mistakenly does not apply
>         (echo y; echo n; echo n) | (cd dir && git checkout -p foo) &&
>         verify_saved_state bar &&
>         verify_state dir/foo head head
>
> ==== xx.
> ==== 1d.
> ==== 10e.
> msys does not support: :(prefix:4)dir/foo
> not ok 13 - path limiting works: foo inside dir
>
> The error message 'msys does not support...' originates from this function
> in git-add--interactive.perl (which is invoked from checkout -p):
>
>   sub run_cmd_pipe {
>         if ($^O eq 'MSWin32' || $^O eq 'msys') {
>                 my @invalid = grep {m/[":*]/} @_;
>                 die "$^O does not support: @invalid\n" if @invalid;
>                 my @args = map { m/ /o ? "\"$_\"": $_ } @_;
>                 return qx{@args};
>         } else {
>                 my $fh = undef;
>                 open($fh, '-|', @_) or die;
>                 return <$fh>;
>         }
>   }
>
> It looks like on Windows we disallow arguments that contain double-quote,
> colon, or asterisk, and otherwise wrap arguments in double-quotes if they
> contain space. Then pass them through qx{}, which I can only guess what it
> does.
>
> This code was introduced in 21e9757e (Hack git-add--interactive to make it
> work with ActiveState Perl, 2007-08-01). The commit message has the
> general statement "It wont work for arguments with special characters
> (like ", : or *)), which I do not know how to interpret: Does ActiveState
> Perl not work with special charactoers, or Windows? Because the latter is
> definitely not true.

>
> Can we be more permissive in the 'my @invalid' check without breaking
> ActiveState Perl?
>
> BTW, there is a similar failure in t7105-reset-patch.sh, which invokes
> 'git reset -p', but I haven't investigate further.
>
> -- Hannes