Async parse (#1045)

* debounce parse made async

* extract common function

* don't go through the server for not parsable documents

* use common code path for calls with and without position

* handle immediate requests asynchronously

* store refs and respond on async process down

* cleanup error codes

:parse_error is reserved for invalid JSON-RPC requests and not LSP errors

* improve LSP compatibility - fill error.data on initialize error

* include version in key

* enqueue parsing requests to the same uri

* fix a few edge cases

apps/language_server/lib/language_server/json_rpc.ex

@@ -67,6 +67,20 @@ defmodule ElixirLS.LanguageServer.JsonRpc do
     end
   end
 
+  defmacro error_response(id, code, message, data) do
+    quote do
+      %{
+        "error" => %{
+          "code" => unquote(code),
+          "message" => unquote(message),
+          "data" => unquote(data)
+        },
+        "id" => unquote(id),
+        "jsonrpc" => "2.0"
+      }
+    end
+  end
+
   ## Utils
 
   def notify(method, params) do
@@ -77,9 +91,14 @@ defmodule ElixirLS.LanguageServer.JsonRpc do
     WireProtocol.send(response(id, result))
   end
 
-  def respond_with_error(id, type, message \\ nil) do
+  def respond_with_error(id, type, message \\ nil, data \\ nil) do
     {code, default_message} = error_code_and_message(type)
-    WireProtocol.send(error_response(id, code, message || default_message))
+
+    if data do
+      WireProtocol.send(error_response(id, code, message || default_message, data))
+    else
+      WireProtocol.send(error_response(id, code, message || default_message))
+    end
   end
 
   def show_message(type, message) do
@@ -226,16 +245,25 @@ defmodule ElixirLS.LanguageServer.JsonRpc do
     end
   end
 
+  # https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#errorCodes
+
+  # Defined by JSON-RPC
   defp error_code_and_message(:parse_error), do: {-32700, "Parse error"}
   defp error_code_and_message(:invalid_request), do: {-32600, "Invalid Request"}
   defp error_code_and_message(:method_not_found), do: {-32601, "Method not found"}
   defp error_code_and_message(:invalid_params), do: {-32602, "Invalid params"}
   defp error_code_and_message(:internal_error), do: {-32603, "Internal error"}
-  defp error_code_and_message(:server_error), do: {-32000, "Server error"}
+
+  # -32099 - -32000 - JSON-RPC reserved error codes
+  # No LSP error codes should be defined between the start and end range.
+  # For backwards compatibility the `ServerNotInitialized` and the `UnknownErrorCode`
+  # are left in the range.
   defp error_code_and_message(:server_not_initialized), do: {-32002, "Server not initialized"}
   defp error_code_and_message(:unknown_error_code), do: {-32001, "Unknown error code"}
 
-  defp error_code_and_message(:request_cancelled), do: {-32800, "Request cancelled"}
+  # -32899 - -32800 - LSP reserved error codes
+  defp error_code_and_message(:request_failed), do: {-32803, "Request cancelled"}
+  defp error_code_and_message(:server_cancelled), do: {-32802, "Server cancelled"}
   defp error_code_and_message(:content_modified), do: {-32801, "Content modified"}
-  defp error_code_and_message(:code_lens_error), do: {-32900, "Error while building code lenses"}
+  defp error_code_and_message(:request_cancelled), do: {-32800, "Request cancelled"}
 end