microsoft/typescript-go · error

request failed: %s

Error message

request failed: %s

What it means

Returned by sendClientRequest when a server-to-client request (e.g. workspace/configuration, client/registerCapability, window/workDoneProgress/create) completes and the client replied with a JSON-RPC error response instead of a result. The %s is resp.Error.String(), so the client's own code and message are embedded. It is a normal protocol-level failure: the request was delivered, the client just refused or failed it.

Source

Thrown at internal/lsp/server.go:683

	defer func() {
		s.pendingServerRequestsMu.Lock()
		defer s.pendingServerRequestsMu.Unlock()
		if respChan, ok := s.pendingServerRequests[*id]; ok {
			close(respChan)
			delete(s.pendingServerRequests, *id)
		}
	}()

	if err := s.send(req.Message()); err != nil {
		return *new(Resp), err
	}

	select {
	case <-ctx.Done():
		return *new(Resp), ctx.Err()
	case resp := <-responseChan:
		if resp.Error != nil {
			return *new(Resp), fmt.Errorf("request failed: %s", resp.Error.String())
		}
		return info.UnmarshalResult(resp.Result)
	}
}

// sendClientRequestFireAndForget sends a request to the client without waiting for a response.
// The response, if any, will be silently ignored by the read loop since no pending channel is registered.
// This means any error returned by the client will not be observed. Use only for requests where the
// response value is not needed (e.g., the client always returns null).
func sendClientRequestFireAndForget[Req, Resp any](s *Server, info lsproto.RequestInfo[Req, Resp], params Req) error {
	id := jsonrpc.NewIDString(fmt.Sprintf("ts%d", s.clientSeq.Add(1)))
	req := info.NewRequestMessage(id, params)
	return s.send(req.Message())
}

func (s *Server) sendResult(id *jsonrpc.ID, result any) error {
	return s.sendResponse(&lsproto.ResponseMessage{
		ID:     id,

View on GitHub (pinned to 1bcfa18d79)

Solutions

1. Read the embedded client error text; it names the client's code (e.g. MethodNotFound, InvalidParams) which pinpoints the cause
2. Gate server-to-client requests on the capabilities returned in initialize before calling them
3. For optional integrations (telemetry, progress), treat this error as non-fatal and degrade gracefully
4. Upgrade the client/editor if the method requires a newer LSP revision

Example fix

// before
resp, err := sendClientRequest(ctx, s, lsproto.WorkspaceConfigurationInfo, params)
if err != nil {
	return zero, err
}

// after - only request configuration when the client supports it
if s.clientCapabilities().Workspace?.Configuration == true {
	resp, err = sendClientRequest(ctx, s, lsproto.WorkspaceConfigurationInfo, params)
}

// before sending any server->client request, check the capability
caps := s.clientCapabilities()
ok := caps.Workspace != nil && caps.Workspace.Configuration != nil && *caps.Workspace.Configuration
if !ok {
	return defaults, nil // skip the request entirely
}

func canRequestConfiguration(caps *lsproto.ClientCapabilities) bool {
	return caps.Workspace != nil &&
		caps.Workspace.Configuration != nil &&
		*caps.Workspace.Configuration
}

resp, err := sendClientRequest(ctx, s, info, params)
if err != nil {
	if strings.Contains(err.Error(), "request failed") {
		// client refused; degrade to default behavior rather than failing the handler
		return defaultValue, nil
	}
	return zero, err
}

When it happens

Trigger: Calling a client capability the client never declared (e.g. sending workspace/configuration to a client without configuration support); client-side handler throws (ServerNotInitialized, InvalidParams from the client); client returns MethodNotFound for an optional request; user closes a progress dialog the server tried to create.

Common situations: Server assumes a capability from initializeOptions that the editor did not advertise; older editor version lacking a newer LSP method; VS Code rejecting window/workDoneProgress/create after the item was already disposed.

Related errors

• -32602
• expected null, got %s
• -32602
• -32600
• Invalid value for ${name}: ${value}

AI-assisted analysis of microsoft/typescript-go@1bcfa18d79 (2026-08-16). Data as JSON: /api/errors/b4929cfa0baf2f43. Report an issue: GitHub.