require_once on a missing file fatals the page
| Introduction | |
| Why missing require_once kills the page | |
| Guard: is_file before require | |
| Fallback chain and single shared copy |
Introduction
A renamed helper file plus a lagging deploy took down every page that rendered our analytics counter. The cause was one line: a bare require_once on a file the server did not have yet. This page shows the failure and the guard pattern that makes optional modules safe.
Author: Arthur Isaev
Why missing require_once kills the page
Unlike a missing function call (catchable Error), a failed require_once is fatal at compile time of that statement: nothing after it runs — no fallback, no counter, no page. In our case the counter class moved from Metrika.php to Metrica.php while hosting still served the old name, so Page::metrika() died on every article. Where the require sat at the top of the file, the entire section went down with it.
$ php -r 'require "/srv/www/.php/_modules/Metrica.php";'
PHP Warning: require(...): Failed opening required ...
PHP Fatal error: Uncaught Error: Failed opening required ...
Guard: is_file before require
Check first, require second. A missing module then skips instead of killing the request:
<?php
$mod = $_SERVER['DOCUMENT_ROOT'] . '/.php/_modules/Metrica.php';
if (is_file($mod)) {
require_once $mod;
return (new \Aredel\Php\Modules\Metrica())->aredel();
}
// ... fall through to the baked-in default below
Fallback chain and single shared copy
Order of preference: shared module file, then a baked-in default
snippet (byte-identical to the module output, so visitors see no
difference). Three copies of the module became one — every extra
copy is another file a partial deploy can miss, which is exactly
the failure we started from. Stale pre-rename files left on the
server are listed for removal; afterwards the fallback only ever
fires on genuinely missing modules.
Full incident record (commit plan 10 timeline, file inventory):
PHP errors: case studies.
Автор статьи: Андрей Олегович
| Development with PHP | |
| require, require_once, include, include_once | |
| require_once on a missing file fatals the page |
