Add get_resource_id() function

[nikic]

This is a more obvious and type-safe form of (int) $resource.

[staabm]

I guess resource-ids will be re-used across request boundaries? if so, should be mentioned somewhere

[TysonAndre]

I'd agree it should be documented. Obviously, this RFC doesn't change the existing behavior, changing it here is definitely out of scope, and the same note also applies to (int)$resource.
(e.g. "currently, resource ids are unique for the lifetime of execution (e.g. an http request in a web server), but this may change, because it's limited to 2**32 on 32-bit platforms)

I guess part of the issue is that it's using an associative array from integers to strings, and that zend_hash_index_del doesn't reset the last array pointer. I guess the only place where this could matter is that long-running 32-bit applications that create a lot of resources would possibly be affected by this (only able to create 4 billion ids in a lifetime for sockets/files, unless I misunderstood how this works), but for 64-bit applications, it doesn't matter.

Alternately, I guess it'd be possible to maintain a "free list" like what objects do so that resource ids can be reused.

php > for ($i = 0; $i < 3; $i++) { $fp = fopen("test$i.out", "w"); echo (int)$fp, "\n"; fclose($fp); $fp = null; }
2
3
4
php > $x = ['a', 'b'];
php > unset($x[1]);
php > $x[] = 'c';
php > var_export($x);
array (
  0 => 'a',
  2 => 'c',
)

ZEND_API void ZEND_FASTCALL zend_list_free(zend_resource *res)
{
	ZEND_ASSERT(GC_REFCOUNT(res) == 0);
	zend_hash_index_del(&EG(regular_list), res->handle);
}

[nikic]

@TysonAndre It's a known issue, see https://bugs.php.net/bug.php?id=47396.

[GrahamCampbell]

@nikic Does this function also work on curl objects?

[nikic]

@GrahamCampbell No.

[GrahamCampbell]

I think it maybe should, since people may be upgrading their code to use get_resource_id, even if it is not PHP 8 only, using the Symfony polyfill. If curl objects are not going to be supported, and resources are ultimately going to be removed, I question why this function was even added. Maybe it should be removed from PHP 8, actually?

[nikic]

I can definitely see the argument for dropping this again, given the progress on resource removal.

[TysonAndre]

Some ideas:

1. Could a new interface LegacyResource be added, and have get_resource_id accept resource|LegacyResource instead of just resource (and make curl handles implement LegacyResource)
2. Could get_resource_id() be changed to accept resource|object, or be replaced with a new function that does (get_resource_or_object_id(), get_internal_handle_id(), etc)