From eb7eea7fa08c826748ecad7746aea6991539439c Mon Sep 17 00:00:00 2001
From: David Sancho Moreno <dsnxmoreno@gmail.com>
Date: Thu, 25 Jul 2024 15:07:11 +0200
Subject: [PATCH] browser_only don't break on multiple args

---
 packages/browser-ppx/ppx.ml             |  1 +
 packages/browser-ppx/tests/use_effect.t | 49 +++++++++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/packages/browser-ppx/ppx.ml b/packages/browser-ppx/ppx.ml
index ab78a58f0..0133c7781 100644
--- a/packages/browser-ppx/ppx.ml
+++ b/packages/browser-ppx/ppx.ml
@@ -289,6 +289,7 @@ module Browser_only = struct
     let add_browser_only_extension expr =
       match expr.pexp_desc with
       | Pexp_apply (_, [ (Nolabel, effect_body) ])
+      | Pexp_apply (_, [ (Nolabel, effect_body); _ ])
         when has_browser_only_attribute effect_body ->
           None
       | Pexp_apply (apply_expr, [ (Nolabel, effect_body); _ ])
diff --git a/packages/browser-ppx/tests/use_effect.t b/packages/browser-ppx/tests/use_effect.t
index c842cb897..2148a6d05 100644
--- a/packages/browser-ppx/tests/use_effect.t
+++ b/packages/browser-ppx/tests/use_effect.t
@@ -74,3 +74,52 @@ Without -js flag, we add the browser_only transformation and browser_only applie
         Runtime.fail_impossible_action_in_ssr "<unkwnown>");
     div ~children:[] () [@JSX]
   [@@react.component]
+
+  $ cat > input.re << EOF
+  >  [@react.component]
+  >  let make = () => {
+  >    let (state, dispatch) = React.useReducer(reducer, initialState);
+  > 
+  >   React.useEffect2(
+  >     [%browser_only
+  >       () => {
+  >            let handler = Js.Global.setTimeout(~f=_ => setDebouncedValue(focusedEntryText), delayInMs);
+  >         Some(_ => Js.Global.clearTimeout(handler));
+  >       }
+  >     ],
+  >     (focusedEntryText, delayInMs),
+  >   );
+  > 
+  >    <div />;
+  >  };
+  > EOF
+
+  $ refmt --parse re --print ml input.re > input.ml
+
+With -js flag everything keeps as it is
+
+  $ ./standalone.exe -impl input.ml -js | ocamlformat - --enable-outside-detected-project --impl
+  let make () =
+    let state, dispatch = React.useReducer reducer initialState in
+    React.useEffect2
+      (fun () ->
+        let handler =
+          Js.Global.setTimeout
+            ~f:(fun _ -> setDebouncedValue focusedEntryText)
+            delayInMs
+        in
+        (Some (fun _ -> Js.Global.clearTimeout handler) [@explicit_arity]))
+      (focusedEntryText, delayInMs);
+    div ~children:[] () [@JSX]
+  [@@react.component]
+
+Without -js flag, we add the browser_only transformation and browser_only applies the transformation to fail_impossible_action_in_ssr
+
+  $ ./standalone.exe -impl input.ml | ocamlformat - --enable-outside-detected-project --impl
+  let make () =
+    let state, dispatch = React.useReducer reducer initialState in
+    React.useEffect2
+      (fun () -> Runtime.fail_impossible_action_in_ssr "<unkwnown>")
+      (focusedEntryText, delayInMs);
+    div ~children:[] () [@JSX]
+  [@@react.component]