framework/console/controllers/MigrateController.php
protected function addDefaultPrimaryKey(&$fields)
    {
        foreach ($fields as $field) {
            if (false !== strripos($field['decorators'], 'primarykey()')) {
                return;
            }
        }
        array_unshift($fields, ['property' => 'id', 'decorators' => 'primaryKey()']);
    }
protected function addDefaultPrimaryKey(&$fields)
    {
        foreach ($fields as $field) {
            if (false !== strripos($field['decorators'], 'primarykey()')) {
                return;
            }
        }
        array_unshift($fields, ['property' => 'id', 'decorators' => 'primaryKey()']);
    }
Adds default primary key to fields list if there's no primary key specified.
@param array $fields parsed fields
@since 2.0.7