Hey Emiel,
On Fri, Sep 3, 2021 at 3:09 PM Emiel Mols <emiel@xxxxxxxx> wrote:
Hello,Our codebase depends on distinguishing whether an instance variable is unset, or simply null:
Can you please share more on how you use this information? Is it for lazy loading something that might not be loadable in the end?
class C { public int $v = 123; }$x = new C; unset($x->v);$y = new C; $u->v = null;In php <8.0 we made this work with @array_key_exists($x, 'v'), which stopped working. isset($x->x) doesn't work, as it will return true for 'null' as well. property_exists($x, 'v') will always return true as long as the variable is declared: php-src here.Apart from using debug_zval_dump (too expensive), any hints?
I think the simplest solution would be to cast the object to an array and you will see that the unset property will not be a key in the array while the null one will be.
Another way to go here would be to use the magic method __get() that would be called on the unset property. But not sure how that fits with your use case.
Also something like this could work: https://3v4l.org/7NL0Y, trying to read the property and handling the Error thrown.
But it all depends on how you use this... Please share more to help you correctly.
This feels like quite the oversight honestly :).
This feels like quite a special use case that could be implemented differently to start with. Please share more information so we can help better.
I guess you have read the rfc that deprecated this in 7.4 and scheduled for later removal: https://wiki.php.net/rfc/deprecations_php_7_4#array_key_exists_with_objects
Best,Emiel
Alex
