Default use_js_string to false

This is not supported by Oxcaml at the moment

Author: vouillon

compiler/bin-js_of_ocaml/check_runtime.ml

@@ -43,6 +43,7 @@ let print_groups output l =
               output_string output (Printf.sprintf "%s\n" name)))
 
 let f (runtime_files, bytecode, target_env) =
+  Config.Flag.set "use-js-string" true;
   Config.set_target `JavaScript;
   Config.set_effects_backend `Disabled;
   Linker.reset ();

compiler/lib/config.ml

@@ -93,7 +93,7 @@ module Flag = struct
 
   let safe_string = o ~name:"safestring" ~default:true
 
-  let use_js_string = o ~name:"use-js-string" ~default:true
+  let use_js_string = o ~name:"use-js-string" ~default:false
 
   let check_magic = o ~name:"check-magic-number" ~default:true
 

compiler/tests-full/dune

@@ -12,6 +12,8 @@
    var
    --debuginfo
    %{lib:stdlib:stdlib.cma}
+   --enable
+   use-js-string
    -o
    %{targets})))
 
@@ -53,6 +55,8 @@
    --pretty
    --debuginfo
    %{dep:shapes.cma}
+   --enable
+   use-js-string
    -o
    %{targets})))
 

lib/tests/test_fun_call.ml

@@ -422,9 +422,7 @@ let%expect_test _ =
   let f = Js.wrap_callback (fun s -> print_endline s) in
   Js.export "f" f;
   let () =
-    Js.Unsafe.fun_call
-      (Js.Unsafe.pure_js_expr "jsoo_exports")##.f
-      [| Js.Unsafe.coerce (Js.string "hello") |]
+    Js.Unsafe.fun_call (Js.Unsafe.pure_js_expr "jsoo_exports")##.f [| Obj.magic "hello" |]
   in
   ();
   [%expect {| hello |}]