handleInitialize tries to register capabilities prematurely

[vytautassurvila]

When csharp-language-server is used with vscode-languageclient then client crashes with error Unhandled method client/registerCapability. If I read code right culprit is in following two lines

csharp-language-server/src/CSharpLanguageServer/Server.fs

Lines 583 to 584 in 520ef35

	let! regResult = lspClient.ClientRegisterCapability(
	{ Registrations = [| didChangeWatchedFilesRegistration |] })

Those do send client/registerCapability to client immediately before emitting initialize result.

According to Lsp initialize request

In addition the server is not allowed to send any requests or notifications to the client until it has responded with an InitializeResult, with the exception that during the initialize request the server is allowed to send the notifications window/showMessage, window/logMessage and telemetry/event as well as the window/showMessageRequest request to the client

https://microsoft.github.io/language-server-protocol/specification#initialize

In order to register dynamic capabilities initialized notification should be used instead:

The server can use the initialized notification for example to dynamically register capabilities

https://microsoft.github.io/language-server-protocol/specification#initialized

And the vscode-languageclient code that starts listening on client/registerCapability only after successful initialization (first and last lines are relevant) https://github.com/microsoft/vscode-languageserver-node/blob/d9eeaf626fd9362eec69fe63322d15760f6794d1/client/src/common/client.ts#L3402-L3430

[razzmatazz]

should be fixed with 333f9f4

releasing 0.4.2 in a moment..

[vytautassurvila]

Thanks, vscode-languageclient does not crash anymore with 0.4.2