Shims should give help message for how to add components

[lolbinarycat]

Problem you are trying to solve

If you try to run a shim from a toolchain that does not have that component, it's not immediatly obvious what the solution is to solve the Unknown binary error.

Solution you'd like

If the toolchain was added via rustup toolchain link, suggest building the component with x.py (oddly, this is the one that is already implemented)

If the toolchain was requested through +TOOLCHAIN or RUSTUP_TOOLCHAIN, emit a help message recommending rustup component add --toolchain TOOLCHAIN COMPONENT.

If the toolchain was the default toolchain, recommend rustup component add COMPONENT (could be merged with previous case for simplicity of implementation)

If the toolchain was from rust-toolchain or rust-toolchain.toml, recommend modifying the file or adding a dir override then adding the component to that toolchain.

Notes

The fact that this is handled for linked toolchains suggests it should probably be handled for other cases too.

The linked toolchain case needs to be checked first because it should always take priority.

[rami3l]

Thanks for the report!

However this is weird to me since I believe we already have tests for that two cases you have mentioned:

rustup/tests/suite/cli_misc.rs

Lines 696 to 734 in 96bd8f2

	#[tokio::test]
	async fn run_rls_when_not_installed() {
	let cx = CliTestContext::new(Scenario::SimpleV2).await;
	cx.config
	.expect(["rustup", "default", "stable"])
	.await
	.is_ok();
	cx.config
	.expect(["rls", "--version"])
	.await
	.with_stderr(snapbox::str![[r#"
	error: 'rls[EXE]' is not installed for the toolchain 'stable-[HOST_TRIPLE]'.
	To install, run `rustup component add rls`
	"#]])
	.is_err();
	}
	#[tokio::test]
	async fn run_rls_when_not_installed_for_nightly() {
	let cx = CliTestContext::new(Scenario::SimpleV2).await;
	cx.config
	.expect(["rustup", "default", "stable"])
	.await
	.is_ok();
	cx.config
	.expect(["rustup", "toolchain", "install", "nightly"])
	.await
	.is_ok();
	cx.config
	.expect(["rls", "+nightly", "--version"])
	.await
	.with_stderr(snapbox::str![[r#"
	error: 'rls[EXE]' is not installed for the toolchain 'nightly-[HOST_TRIPLE]'.
	To install, run `rustup component add --toolchain nightly-[HOST_TRIPLE] rls`
	"#]])
	.is_err();
	}

... would you mind providing a minimal reproduction or at least some pointers so that we can figure out why that wasn't working for you?

[lolbinarycat]

I'm on 1.28.2, and I'm doing this with rust-analyzer +beta.

does the lint only show up on the default toolchain?

[rami3l]

does the lint only show up on the default toolchain?

No, as seen in the second test case.

[rami3l]

I'm on 1.28.2, and I'm doing this with rust-analyzer +beta.

rust-analyzer is a bit particular because it is a DUP_TOOL meaning you can have a local installation that shadows our shim. What does which rust-analyzer say?

PS: Please note that this behavior will change soon with #4324 if you are indeed using our shim.

[rami3l]

As there are currently no further actions to be taken from our side, I'm closing this issue now as stale.

Please feel free to reopen if you have more information to provide.

Have a nice day :)