I was surprised when updating the
nixpkgs-unstable channel today to discover that there’s no prebuilt substitute for
x86_64-darwin. I tracked down the failed build on Hydra and it looks like the culprit was a panic when running tests:
runtime: program exceeds 50-thread limit fatal error: thread exhaustion
Is this an artifact of sandboxing? The tests just passed for me building locally, but I don’t have sandboxing enabled on Darwin.
I’m also not sure how to view the history of this job on Hydra to see if this is just an intermittent failure or not.