2 files changed, 25 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/migration/command_recorder.rb b/activerecord/lib/active_record/migration/command_recorder.rb
index ac7d506fd1..81ef4828f8 100644
--- a/activerecord/lib/active_record/migration/command_recorder.rb
+++ b/activerecord/lib/active_record/migration/command_recorder.rb
@@ -110,7 +110,7 @@ module ActiveRecord
 
       private
 
-        module StraightReversions
+        module StraightReversions # :nodoc:
           private
             { transaction:       :transaction,
               execute_block:     :execute_block,
diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb
index c979aaf0a0..0edaaa0cf9 100644
--- a/activerecord/lib/active_record/migration/compatibility.rb
+++ b/activerecord/lib/active_record/migration/compatibility.rb
@@ -13,9 +13,32 @@ module ActiveRecord
         const_get(name)
       end
 
-      V5_2 = Current
+      V6_0 = Current
+
+      class V5_2 < V6_0
+      end
 
       class V5_1 < V5_2
+        def change_column(table_name, column_name, type, options = {})
+          if adapter_name == "PostgreSQL"
+            clear_cache!
+            sql = connection.send(:change_column_sql, table_name, column_name, type, options)
+            execute "ALTER TABLE #{quote_table_name(table_name)} #{sql}"
+            change_column_default(table_name, column_name, options[:default]) if options.key?(:default)
+            change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
+            change_column_comment(table_name, column_name, options[:comment]) if options.key?(:comment)
+          else
+            super
+          end
+        end
+
+        def create_table(table_name, options = {})
+          if adapter_name == "Mysql2"
+            super(table_name, options: "ENGINE=InnoDB", **options)
+          else
+            super
+          end
+        end
       end
 
       class V5_0 < V5_1