[CLI difference] `cargo test -j4` also sets the number of build jobs

[jalil-salame]

Problem

cargo test and cargo nextest run differ in their API:

Cargo test only has -j/--jobs to specify the parallelism. Nextest uses --build-jobs and --test-threads.

While I do agree with the separation, -j setting just the value for --test-threads is surprising.

Proposed solution

Add a third option: -j/--jobs which sets the value for both --test-threads and --build-jobs, specifying --build-jobs/--test-threads explicitely overrides the value from -j/--jobs.

[sunshowers]

Thanks for the report! Unfortunately -j is already taken for --test-threads, which limits our options.

• I think adding a --jobs that isn't the same as -j is going to be confusing given that constraint.
• Changing -j to mean --jobs would also be confusing. Many people use -j1 in CI to run tests in a single-threaded fashion, knowing that that doesn't affect the number of build jobs.

I think we're just going to have to live with this incompatibility. I think your suggestion would have definitely been better overall, but it's too late to change to that.

[jalil-salame]

Maybe keep it in mind if there ever is a 2.0 release/backwards incompatible release?

[sunshowers]

Yeah, for sure.