Move building constraint to `join_scope` in `Reflection`

1 files changed, 11 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/reflection.rb b/activerecord/lib/active_record/reflection.rb
index 4e3359bb4e..3d3ec862a3 100644
--- a/activerecord/lib/active_record/reflection.rb
+++ b/activerecord/lib/active_record/reflection.rb
@@ -171,7 +171,7 @@ module ActiveRecord
       JoinKeys = Struct.new(:key, :foreign_key) # :nodoc:
 
       def join_keys
-        get_join_keys klass
+        @join_keys ||= get_join_keys(klass)
       end
 
       # Returns a list of scopes that should be applied for this Reflection
@@ -185,11 +185,20 @@ module ActiveRecord
       end
       deprecate :scope_chain
 
-      def join_scope(table, foreign_klass)
+      def join_scope(table, foreign_table, foreign_klass)
         predicate_builder = predicate_builder(table)
         scope_chain_items = join_scopes(table, predicate_builder)
         klass_scope       = klass_join_scope(table, predicate_builder)
 
+        key         = join_keys.key
+        foreign_key = join_keys.foreign_key
+
+        klass_scope.where!(table[key].eq(foreign_table[foreign_key]))
+
+        if klass.finder_needs_type_condition?
+          klass_scope.where!(klass.send(:type_condition, table))
+        end
+
         if type
           klass_scope.where!(type => foreign_klass.base_class.name)
         end