check requires before installing modifiers

[gitmo/Role-Tiny.git] / lib / Role / Tiny.pm

diff --git a/lib/Role/Tiny.pm b/lib/Role/Tiny.pm
index f708a16..21688d4 100644 (file)
--- a/lib/Role/Tiny.pm
+++ b/lib/Role/Tiny.pm
@@ -44,6 +44,7 @@ sub import {
   strict->import;
   warnings->import(FATAL => 'all');
   return if $INFO{$target}; # already exported into this package
+  $INFO{$target}{is_role} = 1;
   # get symbol table reference
   my $stash = _getstash($target);
   # install before/after/around subs
@@ -72,20 +73,25 @@ sub import {
   $APPLIED_TO{$target} = { $target => undef };
 }
 
+sub role_application_steps {
+  qw(_install_methods _check_requires _install_modifiers _copy_applied_list);
+}
+
 sub apply_single_role_to_package {
   my ($me, $to, $role) = @_;
 
   _load_module($role);
 
   die "This is apply_role_to_package" if ref($to);
-  die "${role} is not a Role::Tiny" unless my $info = $INFO{$role};
-
-  $me->_check_requires($to, $role, @{$info->{requires}||[]});
-
-  $me->_install_methods($to, $role);
+  die "${role} is not a Role::Tiny" unless $INFO{$role};
 
-  $me->_install_modifiers($to, $info->{modifiers});
+  foreach my $step ($me->role_application_steps) {
+    $me->$step($to, $role);
+  }
+}
 
+sub _copy_applied_list {
+  my ($me, $to, $role) = @_;
   # copy our role list into the target's
   @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = ();
 }
@@ -171,7 +177,7 @@ sub apply_roles_to_package {
   return $me->apply_role_to_package($to, $roles[0]) if @roles == 1;
 
   my %conflicts = %{$me->_composite_info_for(@roles)->{conflicts}};
-  delete $conflicts{$_} for $me->_concrete_methods_of($to);
+  delete $conflicts{$_} for keys %{ $me->_concrete_methods_of($to) };
   if (keys %conflicts) {
     my $fail = 
       join "\n",
@@ -190,8 +196,27 @@ sub apply_roles_to_package {
     delete $INFO{$to}{methods}; # reset since we're about to add methods
   }
 
-  foreach my $role (@roles) {
-    $me->apply_single_role_to_package($to, $role);
+  # backcompat: allow subclasses to use apply_single_role_to_package
+  # to apply changes.  set a local var so ours does nothing.
+  our %BACKCOMPAT_HACK;
+  if($me ne __PACKAGE__
+      and exists $BACKCOMPAT_HACK{$me} ? $BACKCOMPAT_HACK{$me} :
+      $BACKCOMPAT_HACK{$me} =
+        $me->can('role_application_steps')
+          == \&role_application_steps
+        && $me->can('apply_single_role_to_package')
+          != \&apply_single_role_to_package
+  ) {
+    foreach my $role (@roles) {
+      $me->apply_single_role_to_package($to, $role);
+    }
+  }
+  else {
+    foreach my $step ($me->role_application_steps) {
+      foreach my $role (@roles) {
+        $me->$step($to, $role);
+      }
+    }
   }
   $APPLIED_TO{$to}{join('|',@roles)} = 1;
 }
@@ -237,13 +262,14 @@ sub _composable_package_for {
     $e = "Evaling failed: $@\nTrying to eval:\n${code}" if $@;
   }
   die $e if $e;
-  $me->_install_modifiers($composed_name, $modifiers);
+  $me->_install_modifiers($composed_name, $role);
   $COMPOSED{role}{$composed_name} = 1;
   return $composed_name;
 }
 
 sub _check_requires {
-  my ($me, $to, $name, @requires) = @_;
+  my ($me, $to, $name) = @_;
+  return unless my @requires = @{$INFO{$name}{requires}||[]};
   if (my @requires_fail = grep !$to->can($_), @requires) {
     # role -> role, add to requires, role -> class, error out
     if (my $to_info = $INFO{$to}) {
@@ -303,7 +329,8 @@ sub _install_methods {
 }
 
 sub _install_modifiers {
-  my ($me, $to, $modifiers) = @_;
+  my ($me, $to, $name) = @_;
+  return unless my $modifiers = $INFO{$name}{modifiers};
   if (my $info = $INFO{$to}) {
     push @{$info->{modifiers}}, @{$modifiers||[]};
   } else {
@@ -361,6 +388,11 @@ sub does_role {
   return 0;
 }
 
+sub is_role {
+  my ($me, $role) = @_;
+  return !!$INFO{$role};
+}
+
 1;
 
 =encoding utf-8
@@ -512,7 +544,7 @@ will work for classes but to test a role, one must use ::does_role directly.
 
 Additionally, Role::Tiny will override the standard Perl C<DOES> method
 for your class. However, if C<any> class in your class' inheritance
-heirarchy provides C<DOES>, then Role::Tiny will not override it.
+hierarchy provides C<DOES>, then Role::Tiny will not override it.
 
 =head1 METHODS
 
@@ -538,6 +570,12 @@ resulting class.
 Creates a new class based on base, with the roles composed into it in order.
 New class is returned.
 
+=head2 is_role
+
+ Role::Tiny->is_role('Some::Role1')
+
+Returns true if the given package is a role.
+
 =head1 SEE ALSO
 
 L<Role::Tiny> is the attribute-less subset of L<Moo::Role>; L<Moo::Role> is