The LSP spec for workspace.didChangeWatchedFiles (which dates back to at least version 3.15) allows language servers to expect clients to notify them if certain files change. The language server I’m using relies on these messages to know when to update its dependency tree, and provide information on new dependencies. In the absence of this capability, my only option is to reboot the language server, which requires a considerable delay before language help resumes.
I know Nova makes file watches available in its API, but when I send workspace/didChangeWatchedFiles requests myself, my language server responds with:
{"error":{"code":-32601,"message":"unknown request"}}
I believe this is because the server only registers listeners for workspace/didChangeWatchedFiles if the client advertises the capability to perform watches.