Action Scheduler requirement

The "Action Scheduler" library is required for correct operation of our payment library:

https://github.com/pronamic/wp-pay-core/blob/529e6f2568a3e2fd380b23a08e32cf4b22af42a0/composer.json#L61

https://github.com/pronamic/wp-pay-core/blob/529e6f2568a3e2fd380b23a08e32cf4b22af42a0/src/Plugin.php#L299-L308

In WordPress plugins such as "Pronamic Pay" or "Pronamic Pay with Mollie for Gravity Forms" it is not immediately known in which folder the "Action Scheduler" library is located. However, we need to know this location to load the "Action Scheduler" library. To do this, we pass the "Action Scheduler" location when creating a plugin instance.

\Pronamic\WordPress\Pay\Plugin::instance(
    [
        'file'                 => __FILE__,
        'options'              => [
            'about_page_file' => __DIR__ . '/admin/page-about.php',
        ],
        'action_scheduler'     => __DIR__ . '/packages/woocommerce/action-scheduler/action-scheduler.php',
        'pronamic_service_url' => 'https://api.wp-pay.org/wp-json/pronamic-pay/v1/payments',
    ]
);

https://github.com/pronamic/wp-pronamic-pay/blob/e17985afe9c984ce9748ac956b98f4a12b884797/pronamic-ideal.php#L48C1-L57C3

\Pronamic\WordPress\Pay\Plugin::instance(
    [
        'file'             => __FILE__,
        'action_scheduler' => __DIR__ . '/packages/woocommerce/action-scheduler/action-scheduler.php',
    ]
);

https://github.com/pronamic/wp-pronamic-pay-with-mollie-for-gravity-forms/blob/0b20c960ef8174c12da414b4f1b1aa8b0f4046b8/pronamic-pay-with-mollie-for-gravity-forms.php#L44-L49

This works fine, but we have to define the location of the "Action Scheduler" library in more and more places. For example, while writing PHPUnit tests I also encountered the following error:

require_once(/wp-content/plugins/action-scheduler/action-scheduler.php): Failed to open stream: No such file or directory

I can create the plugin instance in the PHPUnit bootstrap routine and pass the path of the "Action Scheduler", but I also recently came across the following:

\Composer\InstalledVersions::getInstallPath('vendor/package');

https://getcomposer.org/doc/07-runtime.md#knowing-the-path-in-which-a-package-is-installed

Shall we change the following code?

https://github.com/pronamic/wp-pay-core/blob/529e6f2568a3e2fd380b23a08e32cf4b22af42a0/src/Plugin.php#L299-L308

To:

/**
 * Action scheduler.
 *
 * @link https://actionscheduler.org/
 */
$action_scheduler_path = \Composer\InstalledVersions::getInstallPath( 'woocommerce/action-scheduler' );

if ( null === $action_scheduler_path ) {
    throw new \Exception( 'The required Action Scheduler library could not be found.' );
}

require_once $action_scheduler_path . '/action-scheduler.php';

@rvdsteege What do you think? Can \Composer\InstalledVersions::getInstallPath('vendor/package'); be used safely?

pronamic / wp-pay-core

Action Scheduler requirement #154