[flow] Setup types for extra data for detailedly rendered diagonistics

Summary:
In this diff, we setup LSP types for the extra information needed to render detailed errors in vscode. We attach the information in the `data` field of [diagnostic](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#diagnostic), which is guaranteed to not be inspected by standard LSP client, but is something our vscode extension can inspect and do something meaningful.

The rendering protocol will introduce a tight coupling between our language server and client, so I also introduced some version scheme. For now, as I am prototyping, I will start with a simple schema that just dumps the CLI error in plaintext form. Therefore, the schema for our data field is:

```
type Data =
  | null | void
  | { version: 0, rendered: string }
  // | ... to be extended in the future
```

We can continue iterating on the v0 design, since it's still unreleased.

Changelog: [internal]

Reviewed By: panagosg7

Differential Revision: D57169091

fbshipit-source-id: b4dd8ba1031f1384c8aa9e3a44e303b8f53068e4

src/common/flow_lsp_conversions.ml

@@ -251,6 +251,7 @@ let diagnostics_of_flow_errors =
             message = error.Flow_errors_utils.Lsp_output.message;
             tags = [];
             relatedInformation;
+            data = Lsp.PublishDiagnostics.NoExtraDetailedDiagnostic;
           }
         )
     | Error _ -> None

src/hack_forked/utils/lsp/lsp.ml

@@ -749,6 +749,7 @@ module PublishDiagnostics = struct
     message: string;  (** the diagnostic's message *)
     tags: DiagnosticTag.t list;
     relatedInformation: diagnosticRelatedInformation list;
+    data: extraDetailedDiagnostic;
   }
 
   and diagnosticCode =
@@ -760,6 +761,10 @@ module PublishDiagnostics = struct
     relatedLocation: Location.t;  (** wire: just "location" *)
     relatedMessage: string;  (** wire: just "message" *)
   }
+
+  and extraDetailedDiagnostic =
+    | NoExtraDetailedDiagnostic
+    | ExtraDetailedDiagnosticV0 of string
 end
 
 (** DidOpenTextDocument notification, method="textDocument/didOpen" *)

src/hack_forked/utils/lsp/lsp.mli

@@ -592,12 +592,17 @@ module PublishDiagnostics : sig
     message: string;
     tags: DiagnosticTag.t list;
     relatedInformation: diagnosticRelatedInformation list;
+    data: extraDetailedDiagnostic;
   }
 
   and diagnosticRelatedInformation = {
     relatedLocation: Location.t;
     relatedMessage: string;
   }
+
+  and extraDetailedDiagnostic =
+    | NoExtraDetailedDiagnostic
+    | ExtraDetailedDiagnosticV0 of string
 end
 
 module DidOpen : sig

src/hack_forked/utils/lsp/lsp_fmt.ml

@@ -542,16 +542,22 @@ let print_diagnostic (diagnostic : PublishDiagnostics.diagnostic) : json =
         ]
     in
     Jprint.object_opt
-      [
-        ("range", Some (print_range diagnostic.range));
-        ("severity", Base.Option.map diagnostic.severity ~f:print_diagnosticSeverity);
-        ("code", print_diagnosticCode diagnostic.code);
-        ("source", Base.Option.map diagnostic.source ~f:string_);
-        ("message", Some (JSON_String diagnostic.message));
-        ( "relatedInformation",
-          Some (JSON_Array (Base.List.map diagnostic.relatedInformation ~f:print_related))
-        );
-      ]
+      ([
+         ("range", Some (print_range diagnostic.range));
+         ("severity", Base.Option.map diagnostic.severity ~f:print_diagnosticSeverity);
+         ("code", print_diagnosticCode diagnostic.code);
+         ("source", Base.Option.map diagnostic.source ~f:string_);
+         ("message", Some (JSON_String diagnostic.message));
+         ( "relatedInformation",
+           Some (JSON_Array (Base.List.map diagnostic.relatedInformation ~f:print_related))
+         );
+       ]
+      @
+      match diagnostic.data with
+      | PublishDiagnostics.NoExtraDetailedDiagnostic -> []
+      | PublishDiagnostics.ExtraDetailedDiagnosticV0 str ->
+        [("data", Some (JSON_Object [("version", JSON_Number "0"); ("rendered", JSON_String str)]))]
+      )
   )
 
 let print_diagnostic_list (ds : PublishDiagnostics.diagnostic list) : json =
@@ -611,6 +617,9 @@ let parse_diagnostic (j : json option) : PublishDiagnostics.diagnostic =
       tags = Jget.array_d j "tags" ~default:[] |> Base.List.filter_map ~f:DiagnosticTagFmt.of_json;
       relatedInformation =
         Jget.array_d j "relatedInformation" ~default:[] |> Base.List.map ~f:parse_info;
+      (* The parsing is for recovering diagnostics in the code action. The extra detailed one is
+       * not relevant, since it contains the same information as the rest of the diagnostic. *)
+      data = PublishDiagnostics.NoExtraDetailedDiagnostic;
     }
   )
 

src/hack_forked/utils/lsp/lsp_mapper.ml

@@ -239,14 +239,32 @@ let default_mapper =
       (fun _mapper { ConnectionStatus.isConnected } -> { ConnectionStatus.isConnected });
     of_diagnostic =
       (fun mapper
-           { PublishDiagnostics.range; severity; code; source; message; tags; relatedInformation } ->
+           {
+             PublishDiagnostics.range;
+             severity;
+             code;
+             source;
+             message;
+             tags;
+             relatedInformation;
+             data;
+           } ->
         let range = mapper.of_range mapper range in
         let map_related_info { PublishDiagnostics.relatedLocation; relatedMessage } =
           let relatedLocation = mapper.of_location mapper relatedLocation in
           { PublishDiagnostics.relatedLocation; relatedMessage }
         in
         let relatedInformation = Base.List.map ~f:map_related_info relatedInformation in
-        { PublishDiagnostics.range; severity; code; source; message; tags; relatedInformation });
+        {
+          PublishDiagnostics.range;
+          severity;
+          code;
+          source;
+          message;
+          tags;
+          relatedInformation;
+          data;
+        });
     of_definition_params = (fun mapper t -> mapper.of_text_document_position_params mapper t);
     of_definition_result =
       (fun mapper results -> Base.List.map ~f:(mapper.of_location mapper) results);

src/lsp/__tests__/lspErrors_test.ml

@@ -27,6 +27,7 @@ let mk_diagnostic { uri = _; kind; msg } =
     message = msg;
     tags = [];
     relatedInformation = [];
+    data = NoExtraDetailedDiagnostic;
   }
 
 (* Take the json output and convert it back into a list of errors *)

src/lsp/flowLsp.ml

@@ -1135,6 +1135,7 @@ let diagnostic_of_parse_error (loc, parse_error) : PublishDiagnostics.diagnostic
     tags = [];
     message = Parse_error.PP.error parse_error;
     relatedInformation = [];
+    data = PublishDiagnostics.NoExtraDetailedDiagnostic;
   }
 
 let live_syntax_errors_enabled (state : server_state) =

src/lsp/lspErrors.ml

@@ -114,6 +114,7 @@ let limit_errors errors =
           tags = [];
           message;
           relatedInformation = [];
+          data = PublishDiagnostics.NoExtraDetailedDiagnostic;
         }
       in