async rules

[staabm]

in https://github.com/staabm/phpstan-todo-by we have some advanced use-cases in which we trigger http requests from within a rule. in https://github.com/staabm/phpstan-dba I have similar use-cases in which I have to trigger database queries from rules.

I think there are plenty of other use-cases with similar requirements.

did you think about whether rules could return a Promise, so heavy operation could run concurrently and don't block worker processes for things which could happen in the background..?

Alternatively we could think about a Fiber based approach

[ondrejmirtes]

Unfortunately I can't imagine how it could work.. A lot of PHPStan internals would have to be rewritten to be async. And because 100 % of PHPStan's work right now is CPU-bound, it's not worth it because there wouldn't be any advantages.

Since you can ask about the data just once and then cache it, I don't think there would be much advantage in your case either.

[staabm]

I agree that the PHPStan core itself would not benefit from it. on the other hand when I have to trigger db queries or http requests this will considerably slow down overall scanning time, because the worker gets blocked and is waiting for IO.

I can totally see though why this doesn't make sense for the core and I will see whether I can make my extension more effiecient in a different way. thanks for your input.

[ondrejmirtes]

I could imagine a new kind of "collector" rule that would do this but you need it in dynamic return type extensions too and that's hard to do.

[staabm]

For now I will implement a regular collector and do a curl-multi batch request in the rule. Thx for the input

staabm/phpstan-todo-by#77