Fatal Errors vs Errors vs Warnings

Also Known As

TL;DR

Explanation

PHP's error system has multiple levels controlled by error_reporting(). Fatal errors (E_ERROR) stop execution immediately — you cannot catch them with try/catch, only with register_shutdown_function(). Parse errors (E_PARSE) prevent the file loading at all. Warnings (E_WARNING) continue execution but signal something wrong. Notices (E_NOTICE) are advisory — undefined variables, deprecated usages. PHP 7 replaced many engine-level fatals with catchable Error exceptions.

Common Misconception

Why It Matters

Common Mistakes

• Suppressing all errors with error_reporting(0) hiding real bugs
• Not distinguishing Error exceptions (catchable) from true fatals (not catchable)
• Logging warnings at same severity as fatals in monitoring

Code Examples

// Fatal errors were uncatchable in PHP 5:
require 'nonexistent.php'; // Fatal — script dies, no catch possible
call_to_undefined_function(); // Fatal

// PHP 7+: most fatals are now catchable Errors:
try {
    require 'nonexistent.php';
} catch (\Error $e) {
    echo 'Fatal caught: ' . $e->getMessage();
}

// Register shutdown for truly uncatchable fatals:
register_shutdown_function(function() {
    $error = error_get_last();
    if ($error && $error['type'] === E_ERROR) {
        error_log('Fatal: ' . $error['message']);
    }
});

References

• ↗ https://www.php.net/manual/en/errorfunc.constants.php

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