Hello fellow monks,

after working through Moose Best Practices and various discussions, I decided to use build instead of default for my attributes. So far so good.

Now I have a role with lazy attributes that I apply at runtime with Moose::Util qw(apply_all_roles). This also works fine. With one exception. I get the message "You cannot have a lazy attribute (myattr) without specifying a default value for it". Calling the _build function from default works.

From Perl common sense I would say, the object is already built before the Role is applied. So you have to use default values for initialization. And so I do something like:

has 'myattr' => ( 
        is      =>  'ro',
        isa     =>  'Int',
        lazy       => 1,
        default => \&_build_myattr,
        # build      => '_build_myattr',
    );

[download]

Did I miss something?

What are best practises in my case?

Thank you for your thoughts

Update: see comment below, it's a typo. It is a "builder" instead of "build"

And it came to pass that in time the Great God Om spake unto Brutha, the Chosen One: "Psst!"
(Terry Pratchett, Small Gods)

In reply to Moose: apply Role at Runtime (build vs. default) [solved] by Brutha

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