PHP 8.0: catch exceptions only by type

Version8.0
TypeChange

PHP 8.0 and later allows to use try/catch blocks where the catch() statement does not catch the exception itself to a variable.

Prior to PHP 8.0, a typical PHP try/catch block must capture the exception in the catch statement:

try {
  // try something
}
catch (\InvalidArgumentException $ex) { // "$ex" is required
  // handle the exception
}

Sometimes, the exception type (such as \InvalidArgumentException) is enough to determine the way the exception is handled, and capturing the exception to a variable (such as $ex in the example above), PHP 8.0 allows to drop the exception capturing. 

  try {
    $container->get('api-keys.http2-pro');
  }
- catch (NotFoundExceptionInterface $exception) {
+ catch (NotFoundExceptionInterface) {
    $logger->log('API key not set');
  }

A word of caution

Make sure that the exception type you catch is granular enough to convey the meaning of the exception. For example, catching a wildcard \Exception or \Throwable without capturing the exception might be a bad idea if you intend to log the event.

Backwards Compatibility Impact

PHP versions prior to 8.0 will raise a fatal error with the new syntax:

Parse error: syntax error, unexpected ')', expecting '|' or variable (T_VARIABLE) in ... on line ...

It is not possible back-port this functionality to earlier PHP versions.

Related Changes

RFC Discussion Implementation