Fix nullsafe operator on delayed oplines

[iluuu1994]

No description provided.

[cmb69]

This fixes https://bugs.php.net/79995.

[iluuu1994]

@nikic I'd appreciate a review. I'm not sure if there's a better solution that doesn't require tracking the delayed offsets.

[iluuu1994]

I just realized tracking the entire stack was absolutely unnecessary. We're now only storing the last offset. Hopefully this is fine now.

[nikic]

I don't think the last offset is sufficient. Consider something like this:

<?php

$foo = (object) ['bar' => 0];
$array = [[null]];
var_dump($array[0][$foo->bar]?->baz);

You don't want the offset from the $foo->bar.

[iluuu1994]

I don't think the last offset is sufficient. Consider something like this:

😕 You're right. I'll take another look after work.

[iluuu1994]

That was way harder than it should've been. It works now, let me clean it up tomorrow.

[iluuu1994]

Sorry for not getting back to this sooner. Can you give this another review? Can you think of a simpler way to solve this?

Also, maybe we should rename all the short_circuiting stuff to jmp_null_short_circuiting because jmp_null is certainly not the only thing that does short circuiting.

[nikic]

I've opened #6056 with another approach that seems more straightforward to me. What do you think about it?

[iluuu1994]

Closing in favor of #6056.