ZIO Test: Close Resources Earlier In ProvideLayerShared #3696
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iravid
reviewed
May 24, 2020
| * Note that this is only safe if the result of this managed effect is valid | ||
| * outside its scope. | ||
| */ | ||
| def release: ZManaged[R, E, A] = |
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I think there's an issue here in that a *> b.release *> c won't work, as after b.release, the ReleaseMap is already closed.
The workaround may be for this combinator to run self on a nested ReleaseMap.
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Added a test for this. Seems to be working as expected:
testM("closes the scope") {
val expected = Chunk("acquiring a", "acquiring b", "releasing b", "acquiring c", "releasing c", "releasing a")
for {
ref <- Ref.make[Chunk[String]](Chunk.empty)
a = Managed.make(ref.update(_ + "acquiring a"))(_ => ref.update(_ + "releasing a"))
b = Managed.make(ref.update(_ + "acquiring b"))(_ => ref.update(_ + "releasing b"))
c = Managed.make(ref.update(_ + "acquiring c"))(_ => ref.update(_ + "releasing c"))
managed = a *> b.release *> c
_ <- managed.useNow
log <- ref.get
} yield assert(log)(equalTo(expected))
}
iravid
approved these changes
May 25, 2020
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Right now we are keeping resources open too long with
provideLayerShared. Basically we are building one giantZManagedfor all the suites and specs in a test and then running them so the result is we are closing all the shared resources at the end of the spec instead of at the end of the suite they are provided to. To address this I added areleasecombinator onZManagedthat conceptually "closes" the scope.This works but looking at this the
onlycombinator is quite problematic. It requires us to traverse the entire spec, which means acquiring all the resources in any nested suites, to determine whether there is any test annotated withonly. For example if a spec is to be run sequentially we need to acquire and release the resources for suites one by one but we also need to potentially examine all of the suites and acquire their resources to determine which ones we should run. I have removed it for now though it is a very nice combinator and I would like to figure out a way to support it.