1 files changed, 49 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/relation/predicate_builder/polymorphic_array_value.rb b/activerecord/lib/active_record/relation/predicate_builder/polymorphic_array_value.rb
new file mode 100644
index 0000000000..9bb2f8c8dc
--- /dev/null
+++ b/activerecord/lib/active_record/relation/predicate_builder/polymorphic_array_value.rb
@@ -0,0 +1,49 @@
+module ActiveRecord
+  class PredicateBuilder
+    class PolymorphicArrayValue # :nodoc:
+      attr_reader :associated_table, :values
+
+      def initialize(associated_table, values)
+        @associated_table = associated_table
+        @values = values
+      end
+
+      def queries
+        type_to_ids_mapping.map do |type, ids|
+          {
+            associated_table.association_foreign_type.to_s => type,
+            associated_table.association_foreign_key.to_s => ids.size > 1 ? ids : ids.first
+          }
+        end
+      end
+
+      private
+        def type_to_ids_mapping
+          default_hash = Hash.new { |hsh, key| hsh[key] = [] }
+          values.each_with_object(default_hash) { |value, hash| hash[base_class(value).name] << convert_to_id(value) }
+        end
+
+        def primary_key(value)
+          associated_table.association_primary_key(base_class(value))
+        end
+
+        def base_class(value)
+          case value
+          when Base
+            value.class.base_class
+          when Relation
+            value.klass.base_class
+          end
+        end
+
+        def convert_to_id(value)
+          case value
+          when Base
+            value._read_attribute(primary_key(value))
+          when Relation
+            value.select(primary_key(value))
+          end
+        end
+    end
+  end
+end