From 9c194e4860d4dfe999faf49cb0c991f0758664a2 Mon Sep 17 00:00:00 2001
From: Rudi Grinberg <me@rgrinberg.com>
Date: Fri, 18 Nov 2022 07:59:49 -0500
Subject: [PATCH] fix: respect item preSelect capability

Signed-off-by: Rudi Grinberg <me@rgrinberg.com>

ps-id: 3b1a9685-d8f9-4628-9817-5cbd17cf639b
---
 ocaml-lsp-server/src/compl.ml | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/ocaml-lsp-server/src/compl.ml b/ocaml-lsp-server/src/compl.ml
index bbd4c1bd5..ad430c446 100644
--- a/ocaml-lsp-server/src/compl.ml
+++ b/ocaml-lsp-server/src/compl.ml
@@ -264,13 +264,17 @@ let complete (state : State.t)
       match Document.kind doc with
       | `Other -> Fiber.return None
       | `Merlin merlin ->
-        let resolve =
+        let completion_item_capability =
+          let open Option.O in
           let capabilities = State.client_capabilities state in
+          let* td = capabilities.textDocument in
+          let* compl = td.completion in
+          compl.completionItem
+        in
+        let resolve =
           match
             let open Option.O in
-            let* td = capabilities.textDocument in
-            let* compl = td.completion in
-            let* item = compl.completionItem in
+            let* item = completion_item_capability in
             item.resolveSupport
           with
           | None -> false
@@ -290,10 +294,18 @@ let complete (state : State.t)
                   let sortText = Some (sortText_of_index idx) in
                   { ci with sortText })
             in
-            let preselect_first = function
-              | [] -> []
-              | ci :: rest ->
-                { ci with CompletionItem.preselect = Some true } :: rest
+            let preselect_first =
+              match
+                let open Option.O in
+                let* item = completion_item_capability in
+                item.preselectSupport
+              with
+              | None | Some false -> fun x -> x
+              | Some true -> (
+                function
+                | [] -> []
+                | ci :: rest ->
+                  { ci with CompletionItem.preselect = Some true } :: rest)
             in
             let+ construct_cmd_resp, compl_by_prefix_resp =
               Document.Merlin.with_pipeline_exn merlin (fun pipeline ->