If traits are provided but the exporting class does not call

init_meta, we throw an error, instead of just ignoring it.

diff --git a/lib/Moose/Exporter.pm b/lib/Moose/Exporter.pm
index eecb2f7..571c9b2 100644 (file)
--- a/lib/Moose/Exporter.pm
+++ b/lib/Moose/Exporter.pm
@@ -201,8 +201,13 @@ sub _make_sub_exporter_params {
                 $did_init_meta = 1;
             }
 
-            _apply_meta_traits( $CALLER, $traits )
-                if $did_init_meta;
+            if ($did_init_meta) {
+                _apply_meta_traits( $CALLER, $traits );
+            }
+            elsif ( $traits && @{$traits} ) {
+                confess
+                    "Cannot provide traits when $class does not have an init_meta() method";
+            }
 
             goto $exporter;
         };
@@ -218,6 +223,8 @@ sub _strip_traits {
 
     splice @_, $idx, 2;
 
+    $traits = [ $traits ] unless ref $traits;
+
     return ( $traits, @_ );
 }
 
@@ -409,6 +416,18 @@ Moose->init_meta >> to do the real work:
       return Moose->init_meta( @_, metaclass => 'My::Metaclass' );
   }
 
+=head1 METACLASS TRAITS
+
+The C<import> method generated by C<Moose::Exporter> will allow the
+user of your module to specify metaclass traits in a C<-traits>
+parameter passed as part of the import:
+
+  use Moose -traits => 'My::Meta::Trait';
+
+  use Moose -traits => [ 'My::Meta::Trait', 'My::Other::Trait' ];
+
+These traits will be applied to the caller's metaclass instance. These traits will be ignored
+
 =head1 AUTHOR
 
 Dave Rolsky E<lt>autarch@urth.orgE<gt>

diff --git a/t/050_metaclasses/013_metaclass_traits.t b/t/050_metaclasses/013_metaclass_traits.t
index f6519f3..a74fd3c 100644 (file)
--- a/t/050_metaclasses/013_metaclass_traits.t
+++ b/t/050_metaclasses/013_metaclass_traits.t
@@ -3,7 +3,8 @@
 use strict;
 use warnings;
 
-use Test::More 'no_plan';
+use Test::More tests => 23;
+use Test::Exception;
 
 {
     package My::SimpleTrait;
@@ -24,6 +25,16 @@ is( Foo->meta()->simple(), 5,
     'Foo->meta()->simple() returns expected value' );
 
 {
+    package Bar;
+
+    use Moose -traits => 'My::SimpleTrait';
+}
+
+can_ok( Bar->meta(), 'simple' );
+is( Bar->meta()->simple(), 5,
+    'Foo->meta()->simple() returns expected value' );
+
+{
     package My::SimpleTrait2;
 
     use Moose::Role;
@@ -151,3 +162,11 @@ ok( RanOutOfNames->meta()->meta()->has_method('whatever'),
 can_ok( Role::Foo->meta(), 'simple' );
 is( Role::Foo->meta()->simple(), 5,
     'Role::Foo->meta()->simple() returns expected value' );
+
+{
+    require Moose::Util::TypeConstraints;
+    dies_ok( sub { Moose::Util::TypeConstraints->import( -traits => 'My::SimpleTrait' ) },
+             'cannot provide -traits to an exporting module that does not init_meta' );
+    like( $@, qr/does not have an init_meta/,
+          '... and error provides a useful explanation' );
+}