Consider executeCommandProvider for multi server about vscode-extension-samples

[jrieken]

@mtsmfm Can you provide some more context please? Is executeCommandProvider the name of your command. The error you point to happens when registering the same command twice.

[mtsmfm]

@jrieken Sorry for being late.

I created an example extension to describe this problem:

https://github.com/Microsoft/vscode-extension-samples/compare/master...mtsmfm:command-with-multi-server?expand=1

Please try this extension with https://github.com/mtsmfm/example-workspace

This extension just inserts workspace folder name as a code action.
So it should insert file:///path/to/example-workspace/foo for foo/foo.txt and file:///path/to/example-workspace/bar for bar/bar.txt.
But I got file:///path/to/example-workspace/foo for bar/bar.txt.

[mtsmfm]

I met command already exists error.

Actually, we can't notice this error normally because it's suppressed in this line:

https://github.com/Microsoft/vscode-languageserver-node/blob/020764e3eacc76138ffbf63f09489adbfb9e1be8/client/src/client.ts#L2546

[mtsmfm]

@jrieken Isn't this explanation enough?

[mtsmfm]

@jrieken I guess you're busy though, could you have a look at this?
I think this is a critical problem to provide commands/actions from multi-server.

[nwolverson]

I just ran into this, been using a multi-server LSP setup following the example here without realising the major limitation that it won't even initialize if it contains an executeCommandProvider. If it can't be resolved it could at least be listed as a limitation.

(My plan is to avoid executeCommandProvider and manually register/proxy commands to the appropriate LS server)

[Tehnix]

I think this should be related to this one.

What I've ended up doing is using a global clients: Map<string, LanguageClient> (as showed in the multi-server lsp example) and then I locate the correct client for when I have to launch commands. Something like,

async function registerHiePointCommand(name: string,
                                       command: string,
                                       context: ExtensionContext) {
  const editorCmd = commands.registerTextEditorCommand(name, (editor, edit) => {
    const cmd = {
      command,
      arguments: [
        {
          file: editor.document.uri.toString(),
          pos: editor.selections[0].active,
        },
      ],
    };
    // Get the current file and workspace folder.
    const uri = editor.document.uri;
    const folder = workspace.getWorkspaceFolder(uri);
    // If there is a client registered for this workspace, use that client.
    if (clients.has(folder.uri.toString())) {
      const client = clients.get(folder.uri.toString());
      client.sendRequest('workspace/executeCommand', cmd).then(hints => {
        return true;
      }, e => {
        console.error(e);
      });
    }
  });
  context.subscriptions.push(editorCmd);
}

It gets the current file, then looks up the workspace folder. It uses this folder.uri.toString() as the key for the language server.

Then to get rid of the command already exists, I simply check if commands have been registered, else I register them. E.g. a global let hieCommandsRegistered: boolean = false;, and then check if (!hieCommandsRegistered) { ...; hieCommandsRegistered = true; }.