Watch file

[Decodetalkers]

How to watch a file? I found there is a founction did_change_watched_files, how to use it?

[ebkalderon]

Hello there! According to the relevant section in the Language Server Protocol spec, the did_change_watched_files() notification handler will usually not be called unless explicitly registered by the server after it's already initialized, e.g. inside the initialized() notification. Registering for file events looks like this: #190 (comment)

After this has been done, the did_change_watched_files() notification will be called by the client as needed, and the specific file events you asked to be watched will be passed in as params.

[Decodetalkers]

Hello there! According to the relevant section in the Language Server Protocol spec, the did_change_watched_files() notification handler will usually not be called unless explicitly registered by the server after it's already initialized, e.g. inside the initialized() notification. Registering for file events looks like this: #190 (comment)

After this has been done, the did_change_watched_files() notification will be called by the client as needed, and the specific file events you asked to be watched will be passed in as params.

    async fn initialized(&self, _: InitializedParams) {
        let filechangeparms = DidChangeWatchedFilesRegistrationOptions {
            watchers: vec![FileSystemWatcher {
                glob_pattern: "build/CMakeCache.txt".to_string(),
                kind: Some(lsp_types::WatchKind::all()),
            }],
        };
        let registion = Registration {
            id: "myserver-fileWatcher".to_string(),
            method: "workspace/didChangeWatchedFiles".to_string(),
            register_options: Some(serde_json::to_value(filechangeparms).unwrap()),
        };
        self.client
            .register_capability(vec![registion])
            .await
            .unwrap();
        tracing::info!("init");
        //self.client.register_capabilities(vec![registration]).await.unwrap();
        self.client
            .log_message(MessageType::INFO, "initialized!")
            .await;
    }

I try to create , edit CMakeCache.txt any where, but nothing changed
Like this? but it seems not work

[ebkalderon]

Yes, that looks correct. Have you verified on the the LSP client side that it has successfully received the registration and is detecting the file pattern you specified? It is the responsibility of the client to do the actual file watching and to notify the server as needed, after this point.

[Decodetalkers]

Yes, that looks correct. Have you verified on the the LSP client side that it has successfully received the registration and is detecting the file pattern you specified? It is the responsibility of the client to do the actual file watching and to notify the server as needed, after this point.

No, it not, code is here
https://github.com/Decodetalkers/neocmakelsp/blob/filewatcher/src/main.rs#L115
what ever I do with that file, it will not goto this line

[ebkalderon]

Again, it sounds like you may need to look at the messages being sent between the client and server and verify that the client is receiving the registration, is watching for the glob pattern you specified, and that the glob pattern is correct (see the relevant section in the specification).

The client is responsible for actually watching files, not the server, so if the dynamic registration wasn't accepted on the client side (or the pattern is somehow incorrect) then the client will never call did_change_watched_files on the server.

[ratmice]

In the initialize's, InitializeParams you might check the did_change_watched_files field of capabilities.workspace, IIRC this shows whether the client even supports watching files, and there are definitely editors in use that do not.

[Decodetalkers]

In the initialize's, InitializeParams you might check the did_change_watched_files field of capabilities.workspace, IIRC this shows whether the client even supports watching files, and there are definitely editors in use that do not.

It is none, I think I have already set it in initialized..

[Decodetalkers]

In the initialize's, InitializeParams you might check the did_change_watched_files field of capabilities.workspace, IIRC this shows whether the client even supports watching files, and there are definitely editors in use that do not.

neovim/neovim#16078 ohhh, what the.. fuck?

[ratmice]

In the initialize's, InitializeParams you might check the did_change_watched_files field of capabilities.workspace, IIRC this shows whether the client even supports watching files, and there are definitely editors in use that do not.

It is none, I think I have already set it in initialized..

It has been a while since I looked at it, but the None value here, means the client doesn't support it and so registering won't do anything (at best), it isn't required to be supported by the protocol.

In the initialize's, InitializeParams you might check the did_change_watched_files field of capabilities.workspace, IIRC this shows whether the client even supports watching files, and there are definitely editors in use that do not.

neovim/neovim#16078 ohhh, what the.. fuck?

Yeah, my experience too was that I couldn't get it to work in neovim either.

[ebkalderon]

Interesting that Neovim doesn't support this feature yet. In the meantime, are you able to confirm that registering a file watcher works in another editor that supports it? Otherwise, I think this ticket can probably be marked "resolved."