resolve() cannot omit the value.

[shtse8]

the thenable cannot omit the value for resolve().

PHP Fatal error:  Uncaught ArgumentCountError: Too few arguments to function GuzzleHttp\Promise\Promise::resolve(), 0 passed

but it's very useful for just resolve the promise without returning the value.
For ReactPHP and nodejs, we can omit the resolve value and just resolve the promise directly.

[kelunik]

You could just explicitly resolve it with null, not too much of an issue, no?

[shtse8]

yes, but I have to input null for that argument. but its common for other Promise makers design that just resolving with null by default. In most cases, we just want to resolve the promise as the job is completed. but no value needs to be returned.

[Tobion]

Chaning this requires an interface change (PromiseInterface) and a BC break. So it need to wait until the next major version.