Is there a fancy and short solution for using the null coalescing operator with constants in PHP?

Question

Since PHP 8 the constant() function throws an error instead of returning null and generating an E_WARNING when the given constant is not defined, and therefore I can't use the following code to set a variable anymore:

$foo = $SESSION['bar'] ?? constant("MY_CONSTANT") ?? "baz";

My obvious quick solution for this is changing that line to:

$foo = $SESSION['bar'] ?? (defined("MY_CONSTANT") ? constant("MY_CONSTANT") : "baz");

It honestly bothers me a little because I like how the first code is cleaner and do not force me to write ugly giant ternary sequences with a billion parentheses in case I want to add more constants to that ?? cascade. I also tried - hopeless because the (short) documentation around the null coalescing operator already stated that ?? was just a shortcut for isset() in a ternary - the following:

$foo = $SESSION['bar'] ?? MY_CONSTANT ?? "baz";

But it didn't work - as expected. Another solution would be creating a function that returns null when the constant is not defined, such as:

function defined_constant($constant) {

    return (defined($constant) ? constant($constant) : null);

}

$foo = $SESSION['bar'] ?? defined_constant("MY_CONSTANT") ?? "baz";

I would like to know if there's any solution without creating new functions or changing the php.ini file that would allow me use only ?? s as in that first line of code.

It is ok if the answer to my question is just a "no, there is no solution", but I'm intrigued and I can't find much stuff about this on the inte.net. PHP also seems to have just a few native functions around constants (three miscellaneous functions and the get_defined_constants() ?).

Answer 1

true way is detect all undefined constants and define: defined('MY_CONSTANT') || define('MY_CONSTANT', 'baz'); defined('MY_CONSTANT') || define('MY_CONSTANT', 'baz'); and etc.

if you want save this trash constructions, then you can use something like this get_defined_constants()['MY_CONSTANT']?? 'baz' get_defined_constants()['MY_CONSTANT']?? 'baz'