HHVM outputs status code 200 on fatal errors and I can't use fastcgi_next_upstream because of that

Question

I wanted to fallback to next upstream (php5-fpm) on nginx when HHVM fails. This isn't currently possible because HHVM outputs 200 OK response code after fatal error. At least I wanted to give more informative status code.

PHP Error-log:

\nFatal error: $this is null in /data/wordpress/htdocs/wp-content/plugins/woocommerce-gateway-klarna/classes/class-klarna-account.php on line 1231

And I know for sure that it works in php5-fpm.

HHVM version:

hhvm --version
HipHop VM 3.4.0 (rel)
Compiler: tags/HHVM-3.4.0-0-g817b3a07fc4e509ce15635dbc87778e5b3496663
Repo schema: 0e12aaa31fae66b5591f65603de50c9d62caafac
Extension API: 20140829

Answer 1

I fixed this by injecting custom error handler for hhvm.

My index.php for wordpress:

<?php

/**
 * HHVM outputs http status: 200 OK even on fatal errors.
 * Catch fatal errors on HHVM and put right response code.
 */

//Is this HHVM?
if (defined('HHVM_VERSION')) {
  set_error_handler('catch_fatal_error_hhvm',E_ERROR);
}
function catch_fatal_error_hhvm() {
  http_response_code(500);
  die();
}

// WordPress view bootstrapper
define('WP_USE_THEMES', true);
require(dirname( __FILE__ ) . '/wordpress/wp-blog-header.php');