Cannot changeColumn with primary key using MySQL

[rjkip]

When I try to MysqlDriver#changeColumn(), no options are passed to MysqlDriver#createColumnDef() and #createColumnConstraint(). These options are used when changing a primary key. The migration stops here:

if (spec.primaryKey && options.emitPrimaryKey) {
  constraint.push('PRIMARY KEY');

What are these options and what is emitPrimaryKey?

Migration

var dbm = require('db-migrate');
var type = dbm.dataType;

exports.up = function(db, callback) {
    db.changeColumn(
        "users",
        "id",
        {
            type: type.INTEGER,
            primaryKey: true,
            autoIncrement: true
        },
        callback
    );
};

exports.down = function(db, callback) {
    db.changeColumn(
        "users",
        "id",
        {
            type: type.INTEGER,
            primaryKey: true
        },
        callback
    );
};

[kunklejr]

The available column spec options are documented in the README as a subsection to createTable (https://github.com/nearinfinity/node-db-migrate#createtabletablename-columnspec-callback).