Re: Extending an attribute with a trait

Dan,

Yes, there is, if you override the method  
"legal_options_for_inheritance" in Moose::Meta::Attribute in your  
trait so that it includes "foo" as well and that should do it.

- Stevan

On Jul 15, 2008, at 4:55 PM, Dan Harbin wrote:

> Stevan, other Moose-people,
>
> I'm having a problem using an attribute trait in a subclass.  If I
> have an attribute in the superclass, then extend that attribute in the
> subclass by adding a trait, it complains about the behavior I'm adding
> with: Illegal inherited options => (foo).  Since I made "foo"
> required, then I can't add the trait without it complaining: Attribute
> (foo) is required.
>
> The following code demonstrates this issue.  Is there a workaround?
>
> -----------------------
>
> package Demo::Meta::Attribute::Trait::Foo;
> use Moose::Role;
>
> has foo => (
>     is => 'rw',
>     isa => 'Str',
>     required => 1,
> );
>
> package Moose::Meta::Attribute::Custom::Trait::Foo;
> sub register_implementation { 'Demo::Meta::Attribute::Trait::Foo' }
>
> package MyClass;
> use Moose;
>
> has 'one' => (
>     is => 'rw',
>     isa => 'Str',
>     traits => [qw/Foo/],
>     foo => 'bar',
> );
>
> has 'two' => (
>     is => 'rw',
>     isa => 'Str',
> );
>
> package MySubClass;
> use Moose;
> extends 'MyClass';
>
> has '+two' => (
>     traits => [qw/Foo/],
>     foo => 'baz',
> );
>
> package main;
> use strict;
> use warnings;
>
> my $o = MySubClass->new();
>
> 1;