JuniorTheoryCommon

What happens when you run this program?

PHP

<?php

class Ticket
{
    public function __construct(public readonly int $id) {}
}

$t = new Ticket(7);
echo $t->id, "\n";
$t->id = 8;
echo $t->id, "\n";

7, then an Error: cannot modify readonly property

Expecting 8, as if readonly were a note PHP never checks: the property takes its value once, and a second write throws an Error that stops the script.
Expecting the second write to be skipped without a word: PHP never ignores a forbidden write, it throws an Error at that line.

How would you get a ticket with id 8 without breaking readonly?
Why may a readonly property not have a default value?

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JuniorTheoryCommon

What happens when you run this program?

PHP

<?php

class Ticket
{
    public function __construct(public readonly int $id) {}
}

$t = new Ticket(7);
echo $t->id, "\n";
$t->id = 8;
echo $t->id, "\n";

7, then an Error: cannot modify readonly property

Expecting 8, as if readonly were a note PHP never checks: the property takes its value once, and a second write throws an Error that stops the script.
Expecting the second write to be skipped without a word: PHP never ignores a forbidden write, it throws an Error at that line.

How would you get a ticket with id 8 without breaking readonly?
Why may a readonly property not have a default value?

Back to questions Open topic in roadmap →Answer it yourself — Quiz