Is there a way to catch an Exception without having to create a variable?

In PHP, I sometimes catch some exceptions with try/catch :

try {
    ...
} catch (Exception $e) {
    // Nothing, this is normal
}

With that kind of code, I end up with the variable $e that is created for nothing (lots of resources), and PHP_MD (PHP Mess Detector) creates a warning because of an unused variable.

Starting with PHP 8, it is possible to use a non-capturing catch.

This is the relevant RFC, which was voted favourably 48-1.

Now it will be possible to do something like this:

try {
    readFile($file);
} catch (FileDoesNotExist) {
    echo "File does not exist";
} catch (UnauthorizedAccess) {
    echo "User does not have the appropriate permissions to access the file";
    log("User attempted to access $file");
}

With this, for some edge cases where the exception details are not relevant and exception type already provides all the necessary context, it will be possible to catch the exception without creating a new variable.

You can with PHP 8 @see

PHP 5,7

No, but you can unset it.

try {
    ...
} catch (Exception $e) {
    // Nothing, this is normal
    unset($e);
}

If it is PHPMD causing this issue then you can suppress the warning.

PHPMD suppress-warnings

class Bar {
    /**
     * This will suppress UnusedLocalVariable
     * warnings in this method
     *
     * @SuppressWarnings(PHPMD.UnusedLocalVariable)
     */
    public function foo() {

        try {
            ...
        } catch (Exception $e) {
            // Nothing, this is normal
            unset($e);
        }
    }
}

I'm assuming you are only catching the exception because you need to not because you want to. With PHP 5,7 you have to use a catch if you want to use try and if you use a catch you have to declare a variable.