Implement requires on other Role doesn't work?

Question

My first Role is the following one:

package AccBack::RTransaction;

use strict;
use warnings;

use Moose::Role;
use MooseX::Method::Signatures;

requires "_log";
requires "_config";

My second Role, which implement the first Role, is the following one:

package AccBack::RAccounting;

use AccBack::RTransaction;

requires "_log";

has "_config"            => (
    isa         => "Accounting::Config",
    is          => "ro",
    lazy        => 1,
    default     => sub { return Accounting::Config->new(); }
);

has "fibu"              => (
    isa         => "Maybe[Accounting::Fibu]",
    is          => "rw",
    writer      => "setFibu",
    reader      => "getFibu",
    default     => undef,
);

with "AccBack::RTransaction";

My base class is the following one:

package AccBack::Membership;

use AccBack::RAccounting;

has "_log"              => (
    isa         => "Log::Log4perl::Logger",
    is          => "ro",
    default     => sub { 
        return Log::Log4perl->get_logger("AccBack::Membership");
    }
);

has "mailMergeOption"  => (
    isa         => "Maybe[HashRef]",
    is          => "rw",
    writer      => "setMailMergeOption",
    reader      => "getMailMergeOption",
    default     => undef,
);

# Roles
with "AccBack::RAccounting";

If I wan't to start my program, I get this error:

'AccBack::RAccounting' requires the method '_config' to be implemented by 'AccBack::Membership' at C:/strawberry/perl/site/lib/Moose/Meta/Role/Application/ToCla

I don't understand where the problem is. It is the same things as http://search.cpan.org/~doy/Moose-2.0203/lib/Moose/Cookbook/Roles/Recipe1.pod.

Does anybody have an idea about what I've misunderstand?

Just a guess, but does it work if you put the `with` statement towards the top rather than the bottom? — frezik, Aug 25 '11 at 16:56
No, that would guarantee it doesn't work; both 'has' and 'with' are normal runtime function calls. — hdp, Aug 25 '11 at 17:11

score 5 · Accepted Answer · answered Aug 25 '11 at 17:10

This is a known problem that will hopefully be fixed in the future. In the meantime, you should be able to satisfy the requirement in the second role by adding a stub method like this:

sub _config;
has "_config"            => (
    isa         => "Accounting::Config",
    is          => "ro",
    lazy        => 1,
    default     => sub { return Accounting::Config->new(); }
);

The stub sub will fulfill the requirement, but will not get in the way of role application.

Implement requires on other Role doesn't work?

1 Answers1