parallel finalization in Concurrent[Resource]#both #1689
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patseev
changed the title
| @@ -1119,6 +1119,9 @@ abstract private[effect] class ResourceAsync[F[_]] | |||
| override def never[A]: Resource[F, A] = | |||
| Resource.eval(F.never[A]) | |||
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| override def both[A, B](fa: Resource[F, A], fb: Resource[F, B]): Resource[F, (A, B)] = | |||
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Another thought... how does race handle finalizers? The default implementations of both and bothOutcome use racePair, so if we could implement that for Resource, we should get "the right thing" in both/bothOutcome/race for free. @SystemFw @djspiewak what do you think?
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So the problem is that racePair doesn't have any special understanding of the way in which finalizers need to be composed. Ultimately, the "for free" parallelism here, or lack thereof, comes down to the semantics of ap, which underlies tupled, which underlies both. I'm actually relatively certain that it's impossible to get the "right thing" for free here, and it just has to be a bespoke special case. That's okay though so long as we're viewing it as a performance optimization and not as a semantic guarantee.
patseev
changed the title
Fixed the inconsistency between
Resource#bothandAsync[Resource]#both.Now both methods run finalizers in parallel.
Related discussion: #1576