Perl's ExtUtils::MakeMaker fails and proposed fix

Reini Urban rurban@x-ray.at
Mon Jul 11 13:01:00 GMT 2011


2011/7/11 Reini Urban:
> 2011/7/7 Marco Moreno:
>> After doing a little debugging, I discovered why installing ExtUtils::MakeMaker
>> was failing for me.  ExtUtils::MM_Cygwin.pm contains:
>>
>> =item maybe_command
>>
>> If our path begins with F</cygdrive/> then we use C<ExtUtils::MM_Win32>
>> to determine if it may be a command.  Otherwise we use the tests
>> from C<ExtUtils::MM_Unix>.
>>
>> =cut
>>
>> sub maybe_command {
>>    my ($self, $file) = @_;
>>
>>    if ($file =~ m{^/cygdrive/}i) {
>>        return ExtUtils::MM_Win32->maybe_command($file);
>>    }
>>
>>    return $self->SUPER::maybe_command($file);
>> }
>>
>>
>> Obviously, if your cygdrive prefix is something else (e.g. '/'), then
>> this will fail.
>>
>> What do you think of this instead:
>>
>> =item maybe_command
>>
>> Determine whether a file is native to Cygwin by checking whether it
>> resides inside the Cygwin installation (using Windows paths).  If so,
>> use C<ExtUtils::MM_Unix> to determine if it may be a command.
>> Otherwise use the tests from C<ExtUtils::MM_Win32>.
>>
>> =cut
>>
>> sub maybe_command {
>>    my ($self, $file) = @_;
>>
>>    my $cygwin_winpath = Cygwin::posix_to_win_path('/', 1);
>>    my $file_winpath = Cygwin::posix_to_win_path($file, 1);
>>
>>    return ($file_winpath =~ /^${cygwin_winpath}/)
>>        ? $self->SUPER::maybe_command($file)
>>        : ExtUtils::MM_Win32->maybe_command($file);
>> }

I improved it a bit, because I don't like userdata end up in regexp.

    my $cygpath = Cygwin::posix_to_win_path('/', 1);
    my $filepath = Cygwin::posix_to_win_path($file, 1);

    return (substr($filepath,0,length($cygpath)) eq $cygpath)
        ? $self->SUPER::maybe_command($file) 	    # Unix
        : ExtUtils::MM_Win32->maybe_command($file); # Win32


>>
>>
>> This passed all the tests and installed ok for me.  Does this look
>> ok to you and is it reasonable to assume that native Cygwin
>> commands will always be inside the Cygwin installation directory?
>> If this proposed change is worthy of implementing, what is the best
>> way to do it?  rt.cpan.org?
>
> Sorry, I did not come to test this this weekend.
>
> Yes, this uncommon cornercase looks worthy to be fixed.
> Please file a perlbug for this. It should go to rt.perl.org.

I just added it as https://rt.perl.org/rt3/Ticket/Display.html?id=94532
-- 
Reini

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