Tests fail on aarch64

[ysangkok]

Describe the bug
After NixOS upgraded to monad-bytes-1.3.0.4, tests started failing.

To Reproduce

1. Use aarch64 (e.g. Mac M1)
2. Run monad-bayes test suite

Expected behavior
Tests should not fail.

Environment

• OS name + version: nixpkgs with Stackage LTS 23 merged in (i.e. staging branch)
• Version of the code: monad-bayes-1.3.0.4

Additional context

Test run:

• https://hydra.nixos.org/build/295732332

I am posting this because I've gotten the impression that Tweag cares about NixOS, because there are many posts on the blog: https://www.tweag.io/group/nix/

[turion]

Thanks for reporting! I believe this is a known, but not well-documented issue (

monad-bayes/flake.nix

Line 48 in bed154b

# Tier 2 - Not tested in CI (at least for now)

,

monad-bayes/.github/workflows/nix.yml

Line 40 in bed154b

run: nix --print-build-logs build .#packages.${{ matrix.system }}.monad-bayes

). Due to machine-precision issues, floating point number calculations are slightly different on aarch64 than on x86_64. One could work around this by relaxing the equality check in the relevant tests. On the monad-bayes CI, we simply don't test aarch64.

I am posting this because I've gotten the impression that Tweag cares about NixOS, because there are many posts on the blog: https://www.tweag.io/group/nix/

I guess Tweag cares about Nix and employs many Nix developers. But monad-bayes is currently not developed much.

My recommendation is to disable tests on aarch64 for now, or find someone with a Mac who wants to fix the tests.