fix: remove intrusive version checking

Only notify users when all of the following conditions hold:

* The running version of ocamllsp is "official". We don't offer
  suggestions for development versions.

* We know something about the user's version ocamllsp. If the version
  isn't recognized by us, we do not second guess the user.

* We are certain the user is able to upgrade to a newer version. If the
  user is forced to an older version of lsp, we allow him to use the
  plugin without notifications.

ps-id: FC109E94-B57C-4226-9AAE-512F45524A91

CHANGES.md

@@ -1,5 +1,10 @@
 # Change Log
 
+## 1.9.1
+
+- Make the check for out of date ocamllsp more conservative. It will no longer
+  alert the user unless the extension is certain an upgrade is possible (#859)
+
 ## 1.9.0
 
 - Dune syntax highlighting fix (#742)

src/extension_commands.ml

@@ -158,25 +158,15 @@ end = struct
   (** Shows appropriate message for when the [ocaml-lsp] in use by the extension
       doesn't support jumping to holes. *)
   let ocaml_lsp_doesn't_support_holes instance ocaml_lsp =
-    let suggestion =
-      match
-        Ocaml_lsp.is_version_up_to_date ocaml_lsp
-          (Extension_instance.ocaml_version_exn instance)
-      with
-      | Ok is_up_to_date ->
-        if is_up_to_date then
-          (* ocamllsp is "up-to-date", so user needs newer ocaml to get newer
-             ocamllsp, which supports typed holes *)
-          "The extension requires a newer version of `ocamllsp`, which needs a \
-           new version of OCaml. Please, consider upgrading the OCaml version \
-           used in this sandbox."
-        else "Consider upgrading the package `ocaml-lsp-server`."
-      | Error (`Msg m) ->
-        sprintf "There is something wrong with your `ocamllsp`. Error: %s" m
-    in
-    show_message `Warn
-      "The installed version of `ocamllsp` does not support typed holes. %s"
-      suggestion
+    match
+      Ocaml_lsp.is_version_up_to_date ocaml_lsp
+        (Extension_instance.ocaml_version_exn instance)
+    with
+    | Ok () -> ()
+    | Error (`Msg msg) ->
+      show_message `Warn
+        "The installed version of `ocamllsp` does not support typed holes. %s"
+        msg
 
   let current_cursor_pos text_editor =
     let selection = TextEditor.selection text_editor in

src/extension_instance.ml

@@ -113,12 +113,7 @@ end = struct
       (match
          Ocaml_lsp.is_version_up_to_date ocaml_lsp (ocaml_version_exn t)
        with
-      | Ok is_up_to_date ->
-        if not is_up_to_date then
-          show_message `Warn
-            "The installed version of `ocamllsp` is out of date. You may be \
-             missing out on cool features or important bug fixes. Consider \
-             upgrading the package `ocaml-lsp-server`."
+      | Ok () -> ()
       | Error (`Msg m) -> show_message `Warn "%s" m);
       Ok ()
     in

src/ocaml_lsp.ml

@@ -53,64 +53,76 @@ type t =
 
 let get_version_from_serverInfo { serverInfo; experimental_capabilities = _ } =
   match serverInfo with
-  | None -> Error `Missing_serverInfo (* ocamllsp should have [serverInfo] *)
+  | None -> None
   | Some { name; version } ->
-    if String.equal name "ocamllsp" then
-      match version with
-      | None -> Error `ServerInfo_version_missing
-      | Some v -> Ok v
+    if String.equal name "ocamllsp" then version
     else (
       log_chan ~section:"Ocaml_lsp.get_version" `Warn
         "the language server is not ocamllsp";
       (* practically impossible but let's be defensive *)
-      Error `Language_server_isn't_ocamllsp)
+      None)
 
-let get_version_semver t =
-  match get_version_from_serverInfo t with
-  | Ok v -> (
-    match String.split v ~on:'-' |> List.hd with
-    | Some v -> Ok v
-    | None -> Error `Unable_to_parse_version)
-  | Error _ as err -> err
+let lsp_versions =
+  let main =
+    [ ( (4, 12)
+      , [| "1.5.0"
+         ; "1.6.0"
+         ; "1.6.1"
+         ; "1.7.0"
+         ; "1.8.0"
+         ; "1.8.1"
+         ; "1.8.2"
+         ; "1.8.3"
+         ; "1.9.0"
+        |] )
+    ; ((4, 13), [| "1.9.1"; "1.10.0"; "1.10.1" |])
+    ]
+  in
+  let rest =
+    let lsp = [| "1.0.0"; "1.1.0"; "1.2.0"; "1.3.0"; "1.4.0"; "1.4.1" |] in
+    List.range ~start:`inclusive ~stop:`inclusive 6 11
+    |> List.map ~f:(fun minor -> ((4, minor), lsp))
+  in
+  main @ rest
+
+let available_versions version =
+  let prefix = (Ocaml_version.major version, Ocaml_version.minor version) in
+  List.Assoc.find lsp_versions ~equal:Poly.equal prefix
 
 let is_version_up_to_date t ocaml_v =
-  let ocamllsp_version = get_version_semver t in
+  let ocamllsp_version = get_version_from_serverInfo t in
   let res =
+    (* if the server doesn't have a version, we assume it's ancient and we can
+       offer an upgrade *)
     match ocamllsp_version with
-    | Ok v -> (
-      match ocaml_v with
-      | _ when Ocaml_version.(ocaml_v < Releases.v4_06_0) ->
-        Error (`Ocaml_version_not_supported ocaml_v)
-      | _ when Ocaml_version.(ocaml_v < Releases.v4_12_0) ->
-        Ok (String.equal v "1.4.1")
-      | _ when Ocaml_version.(ocaml_v < Releases.v4_13_0) ->
-        Ok (String.equal v "1.9.0")
-      | _ when Ocaml_version.(ocaml_v < Releases.v4_14_0) ->
-        Ok (String.equal v "1.9.1")
-      | _ -> Error (`Ocaml_version_not_supported ocaml_v))
-    | Error e -> Error (`Unexpected e)
+    | None -> (
+      match available_versions ocaml_v with
+      | Some v -> Error (`Newer_available (None, Array.last v))
+      | None -> Ok ())
+    | Some v -> (
+      match available_versions ocaml_v with
+      | None -> Ok ()
+      | Some available -> (
+        match Array.findi available ~f:(fun _ -> String.equal v) with
+        | None -> Ok ()
+        | Some (pos, _) ->
+          let last = Array.length available - 1 in
+          if Int.equal pos last then Ok ()
+          else Error (`Newer_available (Some v, available.(last)))))
   in
   Result.map_error res ~f:(fun err ->
       let msg =
         match err with
-        | `Ocaml_version_not_supported v ->
+        | `Newer_available (old, new_) ->
+          let upgrade =
+            match old with
+            | None -> sprintf "to %s" new_
+            | Some old -> sprintf "%s to %s" old new_
+          in
           sprintf
-            "The installed version of OCaml is not supported by `ocamllsp`: \
-             %s. Consider upgrading OCaml version used in the current sandbox."
-            (Ocaml_version.to_string v)
-        | `Unexpected `Language_server_isn't_ocamllsp ->
-          "Using a language server besides `ocamllsp` isn't expected by this \
-           extension. Please, switch to using `ocamllsp` by installing the \
-           package `ocaml-lsp-server` in your current sandbox."
-        | `Unexpected `Missing_serverInfo
-        | `Unexpected `ServerInfo_version_missing ->
-          "The extension expected the server version to be sent by `ocamllsp`. \
-           It is missing. Please, consider upgrading the package \
-           `ocaml-lsp-server`."
-        | `Unexpected `Unable_to_parse_version ->
-          "The extension was unable to parse `ocamllsp` version. That's \
-           strange. Consider filing an issue on the project GitHub with the \
-           version of your `ocamllsp`."
+            "The is a newer version of ocamllsp available. Consider upgrading \
+             %s"
+            upgrade
       in
       `Msg msg)
 

src/ocaml_lsp.mli

@@ -5,7 +5,7 @@ type t
 val of_initialize_result : LanguageClient.InitializeResult.t -> t
 
 val is_version_up_to_date :
-  t -> Ocaml_version.t -> (bool, [ `Msg of string ]) result
+  t -> Ocaml_version.t -> (unit, [ `Msg of string ]) result
 
 val can_handle_switch_impl_intf : t -> bool