Clearing existing diagnostics when a watched configuration file is modified

[vinistock]

We implemented the following scenario in the Ruby LSP (PR):

1. A user is modifying files. Diagnostics are served using pull diagnostics (textDocument/diagnostic)
2. The user decides to change the configurations for the linter. This is done by editing .rubocop.yml
3. We then reload the linter with the new configurations and clear the existing diagnostics, since they may no longer be valid

The flow of clearing the diagnostics is simply:

1. The server receives a workspace/didChangeWatchedFiles notification including .rubocop.yml
2. We fire textDocument/publishDiagnostics notifications with empty arrays to clear the diagnostics on all currently opened files

However, this does not seem to work. We use the same technique to clear diagnostics on textDocument/didClose and that works properly, but trying to clear the diagnostics when a watched file notification comes in doesn't do anything.

I tried debugging the code for vscode-languageclient to see if our notifications were being received and processed and everything seemed fine, but the diagnostics still won't go away.

Are we doing something incorrectly? Or is this a bug somewhere?

[dbaeumer]

That should work that way. I use the same for ESLint

[vinistock]

The fact that the client doesn't include the configuration file's extension as part of its document selector shouldn't matter, right? That is, the configuration file is YAML, but the client doesn't include YAML in the selector.

Do you have any tips for trying to debug this? It's easy for me to reproduce, so if you can point me to where the clearing of the diagnostics happen I can check what's going on.

[dbaeumer]

The fact that the client doesn't include the configuration file's extension as part of its document selector shouldn't matter, right? That is, the configuration file is YAML, but the client doesn't include YAML in the selector.

That is correct.

Do you have any tips for trying to debug this? It's easy for me to reproduce, so if you can point me to where the clearing of the diagnostics happen I can check what's going on.

You could debug the code here: https://github.com/microsoft/vscode-languageserver-node/blob/dbaeumer/lexical-skunk-aquamarine/client/src/common/client.ts#L1711

This is where the published diagnostics are handled and then passed to the VS Code API here: https://github.com/microsoft/vscode-languageserver-node/blob/dbaeumer/lexical-skunk-aquamarine/client/src/common/client.ts#L1743

Let me know how it goes.