Move join scopes on to the reflection object

Scopes can only ever be *not* reflection objects when they are passed in
to the Reflection constructor.  Given this fact, we can eliminate is_a
checks and an intermediate array object by just asking the reflection
object for join scopes.

1 files changed, 22 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 61a2279292..02aab25610 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -187,6 +187,15 @@ module ActiveRecord
       end
       deprecate :scope_chain
 
+      def join_scopes(table, predicate_builder) # :nodoc:
+        if scope
+          [ActiveRecord::Relation.create(klass, table, predicate_builder)
+            .instance_exec(&scope)]
+        else
+          []
+        end
+      end
+
       def constraints
         chain.map(&:scopes).flatten
       end
@@ -806,6 +815,10 @@ module ActiveRecord
         source_reflection.scopes + super
       end
 
+      def join_scopes(table, predicate_builder) # :nodoc:
+        source_reflection.join_scopes(table, predicate_builder) + super
+      end
+
       def source_type_scope
         through_reflection.klass.where(foreign_type => options[:source_type])
       end
@@ -990,6 +1003,15 @@ module ActiveRecord
         end
       end
 
+      def join_scopes(table, predicate_builder) # :nodoc:
+        scopes = @previous_reflection.join_scopes(table, predicate_builder) + super
+        if @previous_reflection.options[:source_type]
+          scopes + [@previous_reflection.source_type_scope]
+        else
+          scopes
+        end
+      end
+
       def klass
         @reflection.klass
       end