typelevel / typelevel/cats-effect

Some dumped fiber have no trace

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#2,620 3 comments 0 reactions 0 assignees View on GitHub

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Dominant language
Scala
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Merged PRs (30d)
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Description

Run the simple app https://github.com/jilen/fiber-trace-loss (use sbt runProd to trigger app).
Can see following dumps

cats.effect.IOFiber@2fd9bf76 RUNNING
 ├ delay @ controllers.DumpController.obtainDump(DumpController.scala:19)
 ├ delayBy @ controllers.DumpController.peoridicDump(DumpController.scala:15)
 ╰ flatMap @ controllers.DumpController.peoridicDump(DumpController.scala:15)

cats.effect.IOFiber@2774b73d WAITING
cats.effect.IOFiber@27f9edcb WAITING
cats.effect.IOFiber@64869333 WAITING
cats.effect.IOFiber@1a080051 WAITING
cats.effect.IOFiber@2e3e643a WAITING
cats.effect.IOFiber@6d2919e7 WAITING

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

Clone the linked fiber-trace-loss reproduction and run it with sbt runProd; inspect the dump output and the referenced DumpController.scala lines 15 and 19. Trace why the WAITING fibers have no entries while the RUNNING fiber does, and consider how to verify that the reported fibers retain trace information.

Written by the indexing model from the issue text.

Assessment

Tech stack
scala
Domain
backend
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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