1 files changed, 78 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/relation/predicate_builder/association_query_handler.rb b/activerecord/lib/active_record/relation/predicate_builder/association_query_handler.rb
new file mode 100644
index 0000000000..159889d3b8
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/association_query_handler.rb
@@ -0,0 +1,78 @@
+module ActiveRecord
+  class PredicateBuilder
+    class AssociationQueryHandler # :nodoc:
+      def initialize(predicate_builder)
+        @predicate_builder = predicate_builder
+      end
+
+      def call(attribute, value)
+        queries = {}
+
+        table = value.associated_table
+        if value.base_class
+          queries[table.association_foreign_type] = value.base_class.name
+        end
+
+        queries[table.association_foreign_key] = value.ids
+        predicate_builder.build_from_hash(queries)
+      end
+
+      protected
+
+      attr_reader :predicate_builder
+    end
+
+    class AssociationQueryValue # :nodoc:
+      attr_reader :associated_table, :value
+
+      def initialize(associated_table, value)
+        @associated_table = associated_table
+        @value = value
+      end
+
+      def ids
+        case value
+        when Relation
+          value.select(primary_key)
+        when Array
+          value.map { |v| convert_to_id(v) }
+        else
+          convert_to_id(value)
+        end
+      end
+
+      def base_class
+        if associated_table.polymorphic_association?
+          @base_class ||= polymorphic_base_class_from_value
+        end
+      end
+
+      private
+
+      def primary_key
+        associated_table.association_primary_key(base_class)
+      end
+
+      def polymorphic_base_class_from_value
+        case value
+        when Relation
+          value.klass.base_class
+        when Array
+          val = value.compact.first
+          val.class.base_class if val.is_a?(Base)
+        when Base
+          value.class.base_class
+        end
+      end
+
+      def convert_to_id(value)
+        case value
+        when Base
+          value._read_attribute(primary_key)
+        else
+          value
+        end
+      end
+    end
+  end
+end