gv-test-HHVM-PHP-FPM-fallback.php

<?php
/* 
 * Simple function to intentionally crash HHVM and trigger our PHP-FPM fallback
 * 
 * For whatever reason having two "default:"" clauses in a switch statement crashes HHVM but not PHP-FPM
 * In HHVM error logs it causes: Fatal error: Switch statements may only contain one default: clause in /var/www/sites/monittest/index.php on line XX
 * 
 * This can be used to intentionally trigger a fallback from HHVM to PHP-FPM in our system, which normally happens 
 * to avoid scripts with rare HHVM bugs from crashing completely to WSOD, and to keep the server mostly working 
 * if HHVM failed completely, which has happened a couple of times.
 * 
 * We need our monitoring script to be able to differentiate between success with HHVM and success with PHP-FPM,
 * so that we can be notified when the fallback is being used and work to repair HHVM. This can be done accurately
 * with a call to `if (defined('HHVM_VERSION')){}` but that doesn't give us a way to instigate the fallback to 
 * PHP-FPM as it would happen in the wild.
 *
 * This function is designed to crash HHVM and trigger the fallback by triggering an error in HHVM and forcing 
 * PHP-FPM into action. We can use this to make sure the monitoring script reacts as we expect to the fallback.
 * 
 * Note that this function never needs to be run, it's mere presence with two default: clauses will crash the script. 
 * Uncomment the second "default:" and reload to trigger PHP-FPM fallback mode
 */
function gv_test_hhvm_active() {
	$demo_variable = '';
	switch ( $demo_variable ) {
		case 'demo_case':
			break;
		
	 	default:
	 	/*
	 	 * Double default clause breaks HHVM but not PHP-FPM
	 	 * Uncomment second default: below to force HHVM to fail and test 
	 	 * the fallback to PHP-FPM
	 	 */
	 	// default:
	}
}
?>