typelevel / typelevel/fs2

Reactive-streams interop is uncancelable

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bug
Dominant language
Scala
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Merged PRs (30d)
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Description

The implementation still uses an uncancelable async_ call which will hang on CE 3.5: https://github.com/typelevel/fs2/blob/9c523441c8f1770faafb36e01c893218162cdb72/reactive-streams/src/main/scala/fs2/interop/reactivestreams/StreamSubscriber.scala#L223

The java flow interop is fixed, but the fix hasn't been released yet.
Since the reactive-streams interop seems to be deprecated in favor of the flow interop, perhaps just releasing the fixed flow interop is sufficient? Though I noticed that the compiler doesn't seem to actually show any deprecation warnings.

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Research direction

Start with reactive-streams/src/main/scala/fs2/interop/reactivestreams/StreamSubscriber.scala around line 223 and compare it with the already-fixed Java Flow interop. Confirm the uncancelable async_ behavior on CE 3.5, then determine whether releasing the Flow fix resolves this issue or whether the deprecated reactive-streams interop also needs a change; done means cancellation no longer hangs and deprecation behavior is understood.

Written by the indexing model from the issue text.

Assessment

Tech stack
scala
Domain
stream-processing
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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