hphp/hack/manual/apis/Classes/WeakRef/index.md
:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::
( excerpt from http://php.net/manual/en/class.weakref.php )
The WeakRef class provides a gateway to objects without preventing the garbage collector from freeing those objects. It also provides a way to turn a weak reference into a strong one.
final class WeakRef {...}
->__construct(?T $reference)->acquire(): bool->get(): ?T->release(): bool->valid(): bool