PHP handle null handling by exception

Question

Is there a way I can tell PHP to throw an exception when I am trying to access a member or method on a null object?

E.g.:

$x = null;
$x->foo = 5; // Null field access
$x->bar(); // Null method call

Right now, I only get the following errors which are not nice to handle:

PHP Notice:  Trying to get property of non-object in ...
PHP Warning:  Creating default object from empty value in ...
PHP Fatal error:  Call to undefined method stdClass::bar() in ...

I would like to have a specific exception being thrown instead. Is this possible?

Register a global error handler and throw your own exceptions. — Rob
– Rob, Commented Oct 5, 2014 at 16:16

HenryQ · Accepted Answer · 2020-12-03 13:15:20Z

6

Since PHP7 you can catch fatal errors, example below:

$x = null;
try {
    $x->method();
} catch (\Throwable $e) {
    throw new \Exception('$x is null');
}

answered Dec 3, 2020 at 13:15

HenryQ

611 silver badge1 bronze badge

Sign up to request clarification or add additional context in comments.

Comments

James M. Lay · Accepted Answer · 2022-08-07 14:53:58Z

You can turn your warnings into exceptions using set_error_handler() so whenever an warning occurs, it will generate an Exception which you can catch in a try-catch block.

Fatal errors can't be turned into Exceptions, they are designed for PHP to stop asap. However, we can handle the fatal error gracefully by doing some last-minute processing using register_shutdown_function()

<?php

//Gracefully handle fatal errors
register_shutdown_function(function(){
    $error = error_get_last();
    if( $error !== NULL) {
        echo 'Fatal Error';
    }
});

//Turn errors into exceptions
set_error_handler(function($errno, $errstr, $errfile, $errline, array $errcontext) {
    throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
});

try{
    $x = null;
    $x->foo = 5; // Null field access
    $x->bar(); // Null method call
}catch(Exception $ex){
    echo "Caught exception";
}

Pedro Amaral Couto · Accepted Answer · 2014-10-06 15:03:18Z

1

Add this code in the file that is included or executed before anything else:

set_error_handler(
    function($errno, $errstr, $errfile, $errline) {
        throw new \ErrorException($errstr, $errno, 1, $errfile, $errline);
    }
);

answered Oct 6, 2014 at 15:03

Pedro Amaral Couto

2,1361 gold badge15 silver badges15 bronze badges

Comments

Pedro Amaral Couto · Accepted Answer · 2014-10-07 12:21:22Z

Try this code to catch all errors:

<?php    
$_caughtError = false;

register_shutdown_function(
        // handle fatal errors
        function() {
            global $_caughtError;
            $error = error_get_last();
            if( !$_caughtError && $error ) {
                throw new \ErrorException($error['message'],
                                          $error['type'],
                                          2,
                                          $error['file'],
                                          $error['line']);
            }
        }
);

set_error_handler(
    function($errno, $errstr, $errfile, $errline) {
        global $_caughtError;
        $_caughtError = true;
        throw new \ErrorException($errstr, $errno, 1, $errfile, $errline);
    }
);

It should be executed or included before other code.

You can also implement a Singleton to avoid global variables or let it throw two exceptions, if you don't mind.

Amorphous · Accepted Answer · 2018-10-11 23:43:31Z

0

The correct answer should be: NO. This is not possible in any PHP version.

answered Oct 11, 2018 at 23:43

Amorphous

7727 silver badges27 bronze badges

Collectives™ on Stack Overflow

PHP handle null handling by exception

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

5 Answers 5

Comments

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related