How can I use crane with cargo-nextest to get the libtest-json output from nextest?

[matthiasbeyer]

Is there a way to build my derivation with cargoNextest but get the libtest-json as a build output?

Something akin to the following call:

export NEXTEST_EXPERIMENTAL_LIBTEST_JSON=1
cargo nextest \
    --no-tests pass \
    --color never \
    --hide-progress-bar \
    --success-output never \
    --failure-output never \
    --message-format libtest-json > $out/out.json

[ipetkov]

Hi @matthiasbeyer! There's a few ways to do this:

1. You can try setting cargoNextestPartitionsExtraArgs and see if that gets you what you need
2. You can define your own build hook (e.g. preCheck or postCheck or postInstall etc) that performs the operation. cargoNextest is built on top of mkCargoDerivation which is built on top of stdenv.mkDerivation so all the same build hook behavior you'd expect of a regular derivation is possible (though check out the API docs for the full details)
3. You can use mkCargoDerivation directly and specify the command to run

Hope this helps!

[matthiasbeyer]

Thanks, that works like I expected! 🎉