remove duneContexts and call describe contexts from the vscode extension

src/custom_requests.ml

@@ -33,9 +33,3 @@ let typedHoles =
         Jsonoo.Encode.(object_ [ ("uri", string @@ Uri.toString uri ()) ]))
   ; decode_response = Jsonoo.Decode.list Range.t_of_json
   }
-
-let getDuneContexts =
-  { meth = ocamllsp_prefixed "duneContexts"
-  ; encode_params = (fun () -> Jsonoo.Encode.null)
-  ; decode_response = Jsonoo.Decode.(list string)
-  }

src/custom_requests.mli

@@ -20,5 +20,3 @@ val switchImplIntf : (string, string array) custom_request
 val inferIntf : (string, string) custom_request
 
 val typedHoles : (Uri.t, Range.t list) custom_request
-
-val getDuneContexts : (unit, string list) custom_request

src/extension_commands.ml

@@ -191,30 +191,44 @@ let _set_dune_context =
       in
       Window.showQuickPickItems ~choices ~options ()
     in
-    let select_dune_context client =
-      let* candidates =
-        Custom_requests.send_request client Custom_requests.getDuneContexts ()
-      in
-      let* context = select_context candidates in
-      match context with
-      | None (* context selection cancelled *) -> Promise.return ()
-      | Some new_context ->
-        let* () = Settings.set Settings.dune_context_setting new_context in
-        Extension_instance.start_language_server instance
+    let select_dune_context () =
+      match Workspace.rootPath () with
+      | None ->
+        (* Assumes that Dune root matches the workspace root *)
+        Promise.return
+          (show_message
+             `Warn
+             "Project root wasn't found. Can't select Dune context without \
+              project root.")
+      | Some root -> (
+        let* result =
+          let sandbox = Extension_instance.sandbox instance in
+          let cmd =
+            Sandbox.get_command sandbox "dune" [ "describe"; "contexts" ]
+          in
+          let env =
+            Interop.Dict.of_alist [ ("DUNE_CONFIG__GLOBAL_LOCK", "disabled") ]
+          in
+          Cmd.output ~env ~cwd:(Path.of_string root) cmd
+        in
+        match result with
+        | Error msg ->
+          Promise.return
+            (show_message
+               `Warn
+               "Error when calling `dune describe contexts': %s"
+               msg)
+        | Ok output -> (
+          let candidates = String.split output ~on:'\n' in
+          let* context = select_context candidates in
+          match context with
+          | None (* context selection cancelled *) -> Promise.return ()
+          | Some new_context ->
+            let* () = Settings.set Settings.dune_context_setting new_context in
+            Extension_instance.start_language_server instance))
     in
-    match Extension_instance.lsp_client instance with
-    | None -> show_message `Warn "ocamllsp is not running."
-    | Some (client, ocaml_lsp) ->
-      if Ocaml_lsp.can_handle_dune_contexts ocaml_lsp then
-        let (_ : unit Promise.t) = select_dune_context client in
-        ()
-      else
-        (* if ocamllsp doesn't have the capability, recommend updating
-           ocamllsp*)
-        show_message
-          `Warn
-          "The installed version of ocamllsp does not support setting the Dune \
-           context. Consider updating ocamllsp."
+    let (_ : unit Promise.t) = select_dune_context () in
+    ()
   in
   command Extension_consts.Commands.select_dune_context handler
 

src/extension_instance.ml

@@ -113,10 +113,6 @@ end = struct
   let server_options sandbox =
     let args = Settings.(get server_args_setting) |> Option.value ~default:[] in
     let args =
-      (* `handleDuneContexts` capability is already checked when getting the
-         contexts for the `ocaml.select-dune-context` command, so the only way
-         to get here with a version of ocamllsp that doesn't support contexts is
-         if the user adds the `dune.context` setting manually *)
       match Settings.get Settings.dune_context_setting with
       | None -> args
       | Some context -> "--context" :: context :: args

src/ocaml_lsp.ml

@@ -44,15 +44,13 @@ module Experimental_capabilities = struct
     ; handleSwitchImplIntf : bool
     ; handleInferIntf : bool
     ; handleTypedHoles : bool
-    ; handleDuneContexts : bool
     }
 
   let default =
     { interfaceSpecificLangId = false
     ; handleSwitchImplIntf = false
     ; handleInferIntf = false
     ; handleTypedHoles = false
-    ; handleDuneContexts = false
     }
 
   (** Creates [t] given a JSON of form [{ 'handleSwitchImplIntf' : true, .... }] *)
@@ -67,12 +65,10 @@ module Experimental_capabilities = struct
       let handleSwitchImplIntf = has_capability "handleSwitchImplIntf" in
       let handleInferIntf = has_capability "handleInferIntf" in
       let handleTypedHoles = has_capability "handleTypedHoles" in
-      let handleDuneContexts = has_capability "handleDuneContexts" in
       { interfaceSpecificLangId
       ; handleSwitchImplIntf
       ; handleInferIntf
       ; handleTypedHoles
-      ; handleDuneContexts
       }
     with Jsonoo.Decode_error err ->
       show_message
@@ -234,5 +230,3 @@ let can_handle_switch_impl_intf t =
 let can_handle_infer_intf t = t.experimental_capabilities.handleSwitchImplIntf
 
 let can_handle_typed_holes t = t.experimental_capabilities.handleTypedHoles
-
-let can_handle_dune_contexts t = t.experimental_capabilities.handleDuneContexts

src/ocaml_lsp.mli

@@ -13,8 +13,6 @@ val can_handle_infer_intf : t -> bool
 
 val can_handle_typed_holes : t -> bool
 
-val can_handle_dune_contexts : t -> bool
-
 module OcamllspSettingEnable : sig
   include Ojs.T