Runtime: fix for target-env browser

Author: hhugo

CHANGES.md

@@ -14,6 +14,7 @@
 * Runtime/wasm: fix Unix.times (#2096)
 * Ppx: disable spurious warning for unused "self" in object litteral (#2128)
 * Ppx: fix labelled arguments for methods (#2126)
+* Runtime: runtime with target-env=browser should not rely on "require(..)" (#2129)
 
 # 6.2.0 (2025-07-30) - Lille
 

compiler/tests-compiler/target_env.ml

@@ -61,3 +61,47 @@ let () =
  without node filesystem
  Sys.readdir ok
  empty root |}]
+
+module Jsoo = Js_of_ocaml_compiler
+
+class find_require r =
+ object
+ inherit Jsoo.Js_traverse.iter as super
+
+ method! expression e =
+ (match e with
+ | ECall (EVar (Jsoo.Javascript.S { name = Utf8 "require"; loc; _ }), _, args, _)
+ -> (
+ match args with
+ | [ Arg name ] -> (
+ match name with
+ | EStr (Utf8 name) -> r := (name, loc) :: !r
+ | _ -> r := ("<Unknown>", loc) :: !r)
+ | _ -> assert false)
+ | _ -> ());
+ super#expression e
+ end
+
+(* Check target-env=browser doesn't use 'require("node:...")' *)
+let%expect_test _ =
+ let test flags =
+ let r = ref [] in
+ let o = new find_require r in
+ let p = compile_and_parse_whole_program ~flags "" in
+ o#program p;
+ List.iter (fun (name, _loc) -> Printf.eprintf "%s\n" name) !r
+ in
+ test [ "--linkall" ];
+ [%expect
+ {|
+ node:tty
+ node:child_process
+ node:util
+ node:fs
+ node:fs
+ node:fs
+ node:fs
+ node:fs
+ |}];
+ test [ "--linkall"; "--target-env=browser" ];
+ [%expect {| |}]

runtime/js/sys.js

@@ -384,6 +384,14 @@ function caml_sys_temp_dir_name(_unit) {
  }
 }
 
+//Provides: caml_sys_temp_dir_name
+//Requires: caml_string_of_jsstring
+//Version: >= 5.4
+//If: browser
+function caml_sys_temp_dir_name(_unit) {
+ return caml_string_of_jsstring("");
+}
+
 //Provides: caml_sys_convert_signal_number
 //Version: >= 5.4
 function caml_sys_convert_signal_number(signo) {

runtime/js/unix.js

@@ -228,6 +228,14 @@ function caml_strerror(errno) {
  }
 }
 
+//Provides: caml_strerror
+//Requires: unix_error
+//If: browser
+function caml_strerror(errno) {
+ const code = unix_error[errno];
+ code || ("Unknown error " + errno)
+}
+
 //Provides: unix_error_message
 //Alias: caml_unix_error_message
 //Requires: caml_strerror, caml_string_of_jsstring