Start Rls with configuration

[alexheretic]

To configure Rls you must start it then send a workspace/didChangeConfiguration message. Rls triggers a build on startup & whenever configuration is changed.

Normally fine, at startup however this means 2 builds have triggered. 2 bulids on startup can cause 2 builds to happen (at least when the builds were eagerly debounced) and for 2 build fail messages to be sent to the client (if, for example, the project has an invalid Cargo.toml).

Is there/can we add a more graceful way to start Rls with configuration?

[nrc]

cc @Xanewok since I remember discussing this at some point

One easy solution would be to not to do an initial build and just wait for the workspace/didChangeConfiguration message. This is sub-optimal for client which don't send that message on startup, but it's not too bad, just means they don't start the initial build and index until the user starts typing.

Actually, thinking about this, I think we implemented an opt-in version of this where you can start the RLS without an initial build by setting a custom flag on the startup message or something. I don't know what happened to that.

[Xanewok]

Yeah, you're right! We implemented (c2b44b8) additional omitInitBuild param, which when passed (and set to true), didn't automatically start build immediately after initialization to work around this specific problem. Now that I think about it, I probably should've documented that somewhere 😞

[alexheretic]

Cool, thanks guys this seems to do the trick in the initialize message

{
  ...
  initializationOptions: {
    ...
    omitInitBuild: true
  }
}