typelevel / typelevel/fs2

Exception escaping recover block using timed pull?

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bug
Dominant language
Scala
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Forks
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Avg merge
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Merged PRs (30d)
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Description

Using a timed pull to detect idle interval, and restart on exception it appears that exception sometimes escapes the recover block leaking out to IO.

I am not sure why this happens.

  • Scala - 3.1.1
  • fs2 - 3.2.5

Repro

The following ideally should never throw an exception. But unfortunately the inner exception does, randomly.

Scastie,

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the linked Scastie reproduction using Scala 3.1.1 and fs2 3.2.5, focusing on the timed pull and nested recover behavior. Confirm the intermittent exception escape and determine the conditions that trigger it; done means the reproduction no longer leaks the inner exception to IO.

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
30/100

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