typelevel / typelevel/cats

A flaky test fired in `CokleisliSuite` on the Native Platform

Open
#4,639 2 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

testing
Dominant language
Scala
Stars
5.5k
Forks
1.2k
Avg merge
2d 10h
Merged PRs (30d)
5

Description

failing seed for commutative arrow.merge consistent with andThen is dVNwEsHmPBbrOfqLc7p6M8kcaCbC-NI_GSMjih5B6-P=
  ==> X cats.tests.CokleisliSuite.Cokleisli[Id, MiniInt, MiniInt]: commutative arrow.merge consistent with andThen 0.05s munit.FailException: Failing seed: dVNwEsHmPBbrOfqLc7p6M8kcaCbC-NI_GSMjih5B6-P=
  You can reproduce this failure by adding the following override to your suite:
  
    override def scalaCheckInitialSeed = "dVNwEsHmPBbrOfqLc7p6M8kcaCbC-NI_GSMjih5B6-P="
  
  Exception raised on property evaluation.
  > ARG_0: Cokleisli(org.scalacheck.GenArities$$Lambda$66@f16caf12)
  > Exception: java.lang.NullPointerException: null

https://github.com/typelevel/cats/actions/runs/10053191215/job/27785580630#step:14:8034
However, I failed to locally reproduce the issue by running the test suite with the provided seed.

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 linked CI job and CokleisliSuite property “commutative arrow.merge consistent with andThen,” using the reported scalaCheckInitialSeed override. Compare the Native Platform run with local execution to identify the NullPointerException; done means the failure is explained and the property runs reliably on Native Platform.

Written by the indexing model from the issue text.

Assessment

Tech stack
scala
Domain
testing
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Needs clarification
Newbie friendliness
42/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.