queryInterface.addColumn ignores transaction and takes the 'after' option in the wrong place

What was unclear/insufficient/not covered in the documentation

The documentation suggests the after and transaction options are passed in the last options parameters, but in fact after must be specified in the attributes (second to last) and transactions are not working at all.

documentation and tests:

// in the reference - http://docs.sequelizejs.com/class/lib/query-interface.js~QueryInterface.html#instance-method-addColumn
queryInterface.addColumn('tableA', 'columnC', Sequelize.STRING, {
   after: 'columnB' // after option is only supported by MySQL
});

// or in migrations.md - https://github.com/sequelize/sequelize/blob/e7c862833e9ed389a5411c281ab3b8bc80b7a17b/docs/migrations.md
return Promise.all([
    queryInterface.addColumn('Person', 'petName', {
        type: Sequelize.STRING
    }, { transaction: t }),
    queryInterface.addColumn('Person', 'favoriteColor', {
        type: Sequelize.STRING,
    }, { transaction: t })
])

But this is how it actually works for after:

queryInterface.addColumn(
  'account',
  'type',
  {
    type: DataTypes.INTEGER,
    after: 'id',
  }
);

The worse problem are transactions that are not working, here is a simple reproduction migration file:

const { DataTypes } = require('sequelize');

module.exports = {
  up: async queryInterface => {
    const { sequelize } = queryInterface;

    return sequelize.transaction(async transaction => {
      await queryInterface.addColumn(
        'account',
        'type',
        {
          type: DataTypes.INTEGER,
          after: 'id',
        },
        {
          transaction,
        }
      );

      throw new Error('err');
    }
  }
}

The new column will be created every time, no matter if the transaction fails or not.

---

Tested on Sequelize: 5.7.6

[RocheVal]

So I confirm that the problem of rollback come from MySQL and only for DDL statement.

But considering the problem of the “after” attribute, it would be nice to update the doc or to put it in the good place. A second issue link to this problem, is that in Typescript “after” is not present in any Types used by the addColumn function (nor in ModelAttributeColumnOptions | AbstractDataTypeConstructor | AbstractDataType for the “attribute” input and nor in the QueryInterfaceOptions for the “options” input). So Typescript complains that this property doesn’t exist and we have to use @ts-ignore to make it work, which is a bit ugly.

Just for information I’m currently using sequelize 5.21.5 and sequelize-typescript 1.1.0.

[automatensalat]

For everyone running into the same issue: This seems to be a MySQL issue, not the fault of sequelize.

According to the MySQL docs, DDL statements like ALTER COLUMN which are generated by sequelize.addColumn() calls are not subject to transactions and so are not rolled back regardless of whether the transaction fails or succeeds: Some statements cannot be rolled back. In general, these include data definition language (DDL) statements, such as those that create or drop databases, those that create, drop, or alter tables or stored routines. See: https://dev.mysql.com/doc/refman/8.0/en/cannot-roll-back.html