Migrations are generated with syntax error and wrong data type in MySQL

[SOHELAHMED7]

When running $ yii gii/api migrations files are generated with syntax error.

Consider a property/field

test_emails:
          type: array
          x-db-type: JSON
          nullable: false
          default: '[]'

create table are generated fine with no issues.

public function up()
    {
        $this->createTable('{{%table}}', [
            'test_emails' => 'json NOT NULL DEFAULT \'[]\'',

but in case of alter or later modification or adding a property to schema

$this->alterColumn('{{%table}}', 'test_emails', 'longtext NOT NULL DEFAULT '{}''); // quote should be escaped

[SOHELAHMED7]

Note: longtext is alias of json in Mariadb