do not use Undef-Tolerant behaviour on attributes that are capable of handling undef

[gitmo/MooseX-UndefTolerant.git] / lib / MooseX / UndefTolerant / Constructor.pm

package MooseX::UndefTolerant::Constructor;
use Moose::Role;

if ( $Moose::VERSION < 1.9900 ) {
        around('_generate_slot_initializer', sub {
                my $orig = shift;
                my $self = shift;

                # note the key in the params may not match the attr name.
                my $key_name = $self->_attributes->[$_[0]]->init_arg;

                # insert a line of code at the start of the initializer,
                # clearing the param if it's undefined.

                if (defined $key_name)
                {
                    # leave the value unscathed if the attribute's type constraint can
                    # handle undef (or doesn't have one, which implicitly means it can)
                    my $type_constraint = $self->_attributes->[$_[0]]->type_constraint;
                    if ($type_constraint and not $type_constraint->check(undef))
                    {
                        my $tolerant_code = 
                             qq# delete \$params->{'$key_name'} unless # . 
                             qq# exists \$params->{'$key_name'} && defined \$params->{'$key_name'};\n#;

                        return $tolerant_code . $self->$orig(@_);
                    }
                }

                return $self->$orig(@_);
});

no Moose::Role;

1;