How to print the output of craneLib.cargoNextest on success?

[samuelburnham]

When running nix flake check from the quick start template, it will only print to stderr on failure but not when the checks succeed. I'd like to see the output of the cargo-nextest command on success as well, especially when running in CI.

I also tried running craneLib.cargoNextest as a package directly:

packages = {
  test = craneLib.cargoNextest (
    commonArgs
    // {
      inherit cargoArtifacts;
    }
  );
};

but that results in error: unable to execute '/nix/store/<...>-quick-start-nextest-0.1.0/bin/quick-start-nextest': No such file or directory, and the only files in that directory are target.tar.zst and target.tar.zst.prev.

I am able to manually run cargo-nextest with a shell script from e.g. a Fenix toolchain's cargo binary and see the output, but it would be nice to integrate with crane as part of the check suite.

Potentially similar issue: #869

[ipetkov]

Hi @samuelburnham ! Printing build logs is controlled by nix itself. You can pass -L (or --print-build-logs) to print the logs as the derivations are being built which is likely what you'd want to pass in your CI invocation.

For derivations that have already been built, you can use nix log to view their logs, or you can run nix build -L --rebuild to rebuild it from scratch.

Hope this helps!

---

but that results in error: unable to execute '/nix/store/<...>-quick-start-nextest-0.1.0/bin/quick-start-nextest': No such file or directory

This sounds like you may have tried to use nix run .#test, when in reality you should run nix build .#test -L here. The test derivation does not produce any "runnable" binaries; building the derivation is running the tests!

[samuelburnham]

nix build -L --rebuild worked, thanks!