mouse.pl

package Result::User {
    use strict;
    use warnings;
    use utf8;

    sub new { bless {}, shift }

    sub to_model {
        my $self = shift;
        Model::User->new(user => $self);
    }
};

package Model::User {
    use strict;
    use warnings;
    use utf8;
    use Mouse;

    has user => (
        is => "rw",
        isa => "Result::User",
        required => 1,
    );

    has guild_model => (
        is => "rw",
        isa => "Model::User::Guild",
        default => sub {
            my $self = shift;
            Model::User::Guild->new(user_model => $self);
        },
        lazy => 1,
    );

    no Mouse;
};

package Model::User::Guild {
    use strict;
    use warnings;
    use utf8;
    use Mouse;
    use Data::Dumper;

    has user_model => (
        is => "rw",
        isa => "Model::User",
        required => 1,
        weak_ref => 1,
    );

    no Mouse;

    sub join {
        my $self = shift;

        my $user = Result::User->new;

        {
            # guild_modelのuser_modelには、ちゃんとModel::Userのオブジェクトが入っている
            warn Dumper $user->to_model->guild_model;
            # $VAR1 = bless( {
            #         'user_model' => bless( {
            #                 'guild_model' => $VAR1,
            #                 'user' => bless( {}, 'Result::User' )
            #             }, 'Model::User' )
            #     }, 'Model::User::Guild' );
        };

        {
            # 変数にいれるとguild_modelのuser_modelがundefになる。
            my $guild_model = $user->to_model->guild_model;
            warn Dumper $guild_model;
            # $VAR1 = bless( {
            #         'user_model' => undef
            #     }, 'Model::User::Guild' );
        };

        {
            # user_modelを一旦変数に落とすと正常になる
            my $user_model  = $user->to_model;
            my $guild_model = $user_model->guild_model;
            warn Dumper $guild_model;
            # $VAR1 = bless( {
            #         'user_model' => bless( {
            #                 'guild_model' => $VAR1,
            #                 'user' => bless( {}, 'Result::User' )
            #             }, 'Model::User' )
            #     }, 'Model::User::Guild' );
        };
    }
};

Result::User->new->to_model->guild_model->join;