Rails 5: include opclasses in rails 5 schema dump

changelogs/unreleased/rails5-include-opclasses-in-schema-dump.yml

+---
+title: 'Rails 5: include opclasses in rails 5 schema dump'
+merge_request: 21416
+author: Jasper Maes
+type: fixed

config/initializers/postgresql_opclasses_support.rb

@@ -144,7 +144,10 @@ module ActiveRecord
                                  [column, opclass] if opclass
                                end.compact]
 
-              IndexDefinition.new(table_name, index_name, unique, column_names, [], orders, where, nil, using, opclasses)
+              index_attrs = [table_name, index_name, unique, column_names, [], orders, where, nil, using, opclasses]
+              index_attrs.insert(-2, nil) if Gitlab.rails5? # include index comment for Rails 5
+
+              IndexDefinition.new(*index_attrs)
             end
           end.compact
         end
@@ -172,29 +175,38 @@ module ActiveRecord
       def indexes(table, stream)
         if (indexes = @connection.indexes(table)).any?
           add_index_statements = indexes.map do |index|
-            statement_parts = [
-              "add_index #{remove_prefix_and_suffix(index.table).inspect}",
-              index.columns.inspect,
-              "name: #{index.name.inspect}",
-            ]
-            statement_parts << 'unique: true' if index.unique
-
-            index_lengths = (index.lengths || []).compact
-            statement_parts << "length: #{Hash[index.columns.zip(index.lengths)].inspect}" if index_lengths.any?
-
-            index_orders = index.orders || {}
-            statement_parts << "order: #{index.orders.inspect}" if index_orders.any?
-            statement_parts << "where: #{index.where.inspect}" if index.where
-            statement_parts << "using: #{index.using.inspect}" if index.using
-            statement_parts << "type: #{index.type.inspect}" if index.type
-            statement_parts << "opclasses: #{index.opclasses}" if index.opclasses.present?
-
-            "  #{statement_parts.join(', ')}"
+            table_name = remove_prefix_and_suffix(index.table).inspect
+            "  add_index #{([table_name]+index_parts(index)).join(', ')}"
           end
 
           stream.puts add_index_statements.sort.join("\n")
           stream.puts
         end
       end
+
+      def indexes_in_create(table, stream)
+        if (indexes = @connection.indexes(table)).any?
+          index_statements = indexes.map do |index|
+            "    t.index #{index_parts(index).join(', ')}"
+          end
+          stream.puts index_statements.sort.join("\n")
+        end
+      end
+
+      def index_parts(index)
+        index_parts = [
+          index.columns.inspect,
+          "name: #{index.name.inspect}",
+        ]
+        index_parts << "unique: true" if index.unique
+        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_parts << "type: #{index.type.inspect}" if index.type
+        index_parts << "opclasses: #{index.opclasses.inspect}" if index.opclasses.present?
+        index_parts << "comment: #{index.comment.inspect}" if Gitlab.rails5? && index.comment
+        index_parts
+      end
   end
 end