Why is my custom error handler not called?

Question

When my script starts, I have:

error_reporting(E_ALL);
ini_set('display_errors', TRUE);
ini_set('display_startup_errors', TRUE);

And then, I register my custom error handler with PHP:

function handleError($code, $text, $file, $line) {
    echo "&%!!";
    return true;
}

set_error_handler('handleError');

Next, there comes some code that produces an error like this:

Fatal error: Call to undefined method DB::getInstanceForDB() in /Applications/MAMP/htdocs/mysite/classes/Test.php on line 32

I keep getting the standard PHP error message box with call stack and everything on my site, no matter if I specify a custom error handler or not. Any idea what's wrong?

Edit: No matter if I return true or not, it doesn't call my custom handler.

Answer 1

First, you need to make your error handling function return true. From set_error_handler:

If the function returns FALSE then the normal error handler continues.

Second, be aware that fatal errors aren't handled by set_error_handler. You need to use register_shutdown_function as well. So your code should look like this:

// Handles non-fatal errors
function handleError($code, $text, $file, $line) {
    var_dump($code);
    return true;
}
set_error_handler('handleError');

// Handles fatal errors
function fatalShutdown() {
    var_dump(error_get_last());
}
register_shutdown_function('fatalShutdown');

Answer 2

In your question, you're telling you are getting a Fatal Error.

I don't think you can catch those, as they are... well... Fatal.

Quoting set_error_handler :

The following error types cannot be handled with a user defined function: E_ERROR, E_PARSE, E_CORE_ERROR, E_CORE_WARNING, E_COMPILE_ERROR, E_COMPILE_WARNING, and most of E_STRICT raised in the file where set_error_handler() is called.