Add default_index_type? to the generic schema dumper doesn't have the knowledge about an index type

Author: kamipo

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -509,6 +509,10 @@ def combine_bind_parameters(
         result
       end
 
+      def default_index_type?(index) # :nodoc:
+        index.using.nil?
+      end
+
       private
 
         def initialize_type_map(m)

activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb

@@ -651,6 +651,10 @@ def valid_type?(type)
         !native_database_types[type].nil?
       end
 
+      def default_index_type?(index) # :nodoc:
+        index.using == :btree || super
+      end
+
       private
 
         def initialize_type_map(m)

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -402,6 +402,10 @@ def postgresql_version
         @connection.server_version
       end
 
+      def default_index_type?(index) # :nodoc:
+        index.using == :btree || super
+      end
+
       private
 
         # See http://www.postgresql.org/docs/current/static/errcodes-appendix.html

activerecord/lib/active_record/schema_dumper.rb

@@ -188,7 +188,7 @@ def index_parts(index)
         index_parts << "length: { #{format_options(index.lengths)} }" if index.lengths.present?
         index_parts << "order: { #{format_options(index.orders)} }" if index.orders.present?
         index_parts << "where: #{index.where.inspect}" if index.where
-        index_parts << "using: #{index.using.inspect}" if index.using && index.using != :btree
+        index_parts << "using: #{index.using.inspect}" if !@connection.default_index_type?(index)
         index_parts << "type: #{index.type.inspect}" if index.type
         index_parts << "comment: #{index.comment.inspect}" if index.comment
         index_parts