typelevel / typelevel/fs2

Some pipes occasionally get ahead when broadcasting through multiple pipes.

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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

Some pipes occasionally get ahead by 1 element when broadcasting an un-chunked stream through multiple pipes using broadcastThrough.

A reproduction of the issue, using Scala 2.13.6 and fs2 3.1.1, can be found in this project or on scastie.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  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 reproduction in src/main/scala/snippets/BroadcastingRace.scala from the linked project, using the Scala 2.13.6 and fs2 3.1.1 setup described. Trace the un-chunked stream through broadcastThrough and reproduce the race; done means multiple pipes no longer get ahead by one element.

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
Mostly clear
Newbie friendliness
25/100

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