Support passing arguments down to cargo subprocess (ie --)

[epage]

Status:

• cargo run
• cargo test
• cargo build: doesn't support --.

As we add new sub-commands, we'll need to remember to take this into account. That means it should be documented somewhere. Possibilities include cargo.rs, PR template, and contributing guide.

[epage]

I thought I remember some extra flags for these but running cargo build -- --help errors.

[roblabla]

I don't think cargo build supports --. cargo run does, it passes the args to the underlying process. cargo test does, it passes the args to the test runner (e.g. cargo test -- --nocapture to print stdout). cargo rustc does, it passes the args to the compiler. Same deal for cargo rustdoc.

There's a general pattern: -- is to pass arguments down to a subprocess that cargo is "hiding".

[epage]

Oh, when I ran cargo test, I ignored it once I saw it compiling. It does support -- --help. It just needs to build all of the test targets first so it has something to call --help on.

[epage]

Thanks, I've updated the title and issue.