bump version to 0.63

[gitmo/Moose.git] / lib / Moose / Util / MetaRole.pm

diff --git a/lib/Moose/Util/MetaRole.pm b/lib/Moose/Util/MetaRole.pm
index 5c61939..74b8547 100644 (file)
--- a/lib/Moose/Util/MetaRole.pm
+++ b/lib/Moose/Util/MetaRole.pm
@@ -3,24 +3,36 @@ package Moose::Util::MetaRole;
 use strict;
 use warnings;
 
+our $VERSION   = '0.63';
+$VERSION = eval $VERSION;
+our $AUTHORITY = 'cpan:STEVAN';
+
 use List::MoreUtils qw( all );
 
+my @Classes = qw( constructor_class destructor_class error_class );
+
 sub apply_metaclass_roles {
     my %options = @_;
 
     my $for = $options{for_class};
 
-    my $meta = _make_new_metaclass( $for, \%options );
+    my %old_classes
+        = map { $_ => $for->meta->$_ } grep { $for->meta->can($_) } @Classes;
 
-    for my $tor_class ( grep { $options{ $_ . '_roles' } }
-        qw( constructor_class destructor_class ) ) {
+    my $meta = _make_new_metaclass( $for, \%options );
 
-        my $class = _make_new_class(
-            $meta->$tor_class(),
-            $options{ $tor_class . '_roles' }
-        );
+    for my $c ( grep { $meta->can($_) } @Classes ) {
+        if ( $options{ $c . '_roles' } ) {
+            my $class = _make_new_class(
+                $meta->$c(),
+                $options{ $c . '_roles' }
+            );
 
-        $meta->$tor_class($class);
+            $meta->$c($class);
+        }
+        else {
+            $meta->$c( $old_classes{$c} );
+        }
     }
 
     return $meta;
@@ -44,8 +56,6 @@ sub _make_new_metaclass {
 
     my $old_meta = $for->meta();
 
-    Class::MOP::remove_metaclass_by_name($for);
-
     # This could get called for a Moose::Meta::Role as well as a Moose::Meta::Class
     my %classes = map {
         $_ => _make_new_class( $old_meta->$_(), $options->{ $_ . '_roles' } )
@@ -84,7 +94,7 @@ sub _make_new_class {
 
     return $existing_class unless $roles;
 
-    my $meta = $existing_class->meta();
+    my $meta = Class::MOP::Class->initialize($existing_class);
 
     return $existing_class
         if $meta->can('does_role') && all { $meta->does_role($_) } @{$roles};
@@ -205,6 +215,44 @@ once.
 
 This function will apply the specified roles to the object's base class.
 
+=head1 PROBLEMS WITH METACLASS ROLES AND SUBCLASS
+
+Because of the way this module works, there is an ordering problem
+which occurs in certain situations. This sequence of events causes an
+error:
+
+=over 4
+
+=item 1.
+
+There is a class (ClassA) which uses some extension(s) that apply
+roles to the metaclass.
+
+=item 2.
+
+You have another class (ClassB) which wants to subclass ClassA and
+apply some more extensions.
+
+=back
+
+Normally, the call to C<extends> will happen at run time, I<after> the
+additional extensions are applied. This causes an error when we try to
+make the metaclass for ClassB compatible with the metaclass for
+ClassA.
+
+We hope to be able to fix this in the future.
+
+For now the workaround is for ClassB to make sure it extends ClassA
+I<before> it loads extensions:
+
+  package ClassB;
+
+  use Moose;
+
+  BEGIN { extends 'ClassA' }
+
+  use MooseX::SomeExtension;
+
 =head1 AUTHOR
 
 Dave Rolsky E<lt>autarch@urth.orgE<gt>