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

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

diff --git a/lib/MooseX/UndefTolerant/Constructor.pm b/lib/MooseX/UndefTolerant/Constructor.pm
index 841811d..969faca 100644 (file)
--- a/lib/MooseX/UndefTolerant/Constructor.pm
+++ b/lib/MooseX/UndefTolerant/Constructor.pm
@@ -1,26 +1,33 @@
 package MooseX::UndefTolerant::Constructor;
 use Moose::Role;
 
-around('_generate_slot_initializer', sub {
-        my $orig = shift;
-        my $self = shift;
+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;
+                # 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.
+                # insert a line of code at the start of the initializer,
+                # clearing the param if it's undefined.
 
-        if (defined $key_name) {
-                my $tolerant_code = 
-                     qq# delete \$params->{'$key_name'} unless # . 
-                     qq# exists \$params->{'$key_name'} && defined \$params->{'$key_name'};\n#;
+                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 $tolerant_code . $self->$orig(@_);
-        }
-        else {
                 return $self->$orig(@_);
-        }
 });
 
 no Moose::Role;