target_dir of cargo doesn't seem to be used.

[Stargateur]

According to this pull request #793, RLS should use cargo target_dir config and join it with rls. However, this doesn't work, I have a .cargo/config in my project, cargo correctly use my custom target_dir, but RLS seem to ignore it and build into target/rls. Maybe this feature only work for cargo config that are more global ? (in the home for exemple).

Also, I found that the behavior of target-dir is ambigus, in one way we could suppose that it's only for the root directory target by default. But it's seem to be for the full path target/rls. That confuse with the pull request that claim use default from cargo.

Maybe, it would be better to split this into two variables (target-dir-cargo, target-dir), or maybe use a totally different directory target for cargo and just rls for RLS ? Currently, I think the behavior is a little odd, and also not documented.

I ask this cause this trouble me when using ide-rust rust-lang/atom-ide-rust#110.

[alexheretic]

Yep the code seems to want to infer cargo-target-dir + "rls", but this didn't work when tested.

Code:

rls/src/config.rs

Lines 245 to 280 in f024cdb

	pub fn infer_defaults(&mut self, project_dir: &Path) -> CargoResult<()> {
	// Note that this may not be equal build_dir when inside a workspace member
	let manifest_path = important_paths::find_root_manifest_for_wd(project_dir)?;
	trace!("root manifest_path: {:?}", &manifest_path);
	let shell = Shell::from_write(Box::new(sink()));
	let cwd = env::current_dir().expect("failed to get cwd");
	let config = CargoConfig::new(shell, cwd, homedir(project_dir).unwrap());
	let ws = Workspace::new(&manifest_path, &config)?;
	// Constructing a `Workspace` also probes the filesystem and detects where to place the
	// build artifacts. We need to rely on Cargo's behaviour directly not to possibly place our
	// own artifacts somewhere else (e.g. when analyzing only a single crate in a workspace)
	match self.target_dir {
	// We require an absolute path, so adjust a relative one if it's passed.
	Inferrable::Specified(Some(ref mut path)) if path.is_relative() => {
	*path = project_dir.join(&path);
	}
	_ => {}
	}
	if self.target_dir.as_ref().is_none() {
	let target_dir = ws.target_dir().into_path_unlocked();
	let target_dir = target_dir.join("rls");
	self.target_dir.infer(Some(target_dir));
	trace!(
	"For project path {:?} Cargo told us to use this target/ dir: {:?}",
	project_dir,
	self.target_dir.as_ref().as_ref().unwrap(),
	);
	}
	Ok(())
	}
	}

We should investigate and probably add a test for this.