Change deprecated modules in a separate directory

Signed-off-by: Rudi Grinberg <rudi.grinberg@gmail.com>

src/dir_contents.ml

@@ -198,7 +198,7 @@ end = struct
       | Yes_with_transition _ ->
         ( wrap_modules modules
         , Module.Name.Map.remove modules main_module_name
-          |> Module.Name.Map.map ~f:Module.deprecate
+          |> Module.Name.Map.map ~f:Module.wrapped_compat
         )
     in
     let alias_module =

src/lib_rules.ml

@@ -413,13 +413,13 @@ module Gen (P : Install_rules.Params) = struct
          else
            acc)
      in
-     let deprecated_modules = Module.Name.Map.values wrapped_compat in
+     let wrapped_compat = Module.Name.Map.values wrapped_compat in
      (* deprecated modules have implementations so we can just append them *)
      let top_sorted_modules =
        Ocamldep.Dep_graph.top_closed_implementations dep_graphs.impl modules
-       >>^ fun modules -> modules @ deprecated_modules
+       >>^ fun modules -> modules @ wrapped_compat
      in
-     (let modules = modules @ deprecated_modules in
+     (let modules = modules @ wrapped_compat in
         List.iter Mode.all ~f:(fun mode ->
        build_lib lib ~scope ~flags ~dir ~obj_dir ~mode ~top_sorted_modules
          ~modules)));

src/module.ml

@@ -164,7 +164,7 @@ let to_sexp { name; impl; intf; obj_name ; pp } =
     ; "pp", (option string) (Option.map ~f:(fun _ -> "has pp") pp)
     ]
 
-let deprecate t =
+let wrapped_compat t =
   { t with
     intf = None
   ; impl =
@@ -176,6 +176,12 @@ let deprecate t =
           | Some intf, _ -> intf.path
           | None, None -> assert false
         in
+        let path =
+          Path.L.relative (Path.parent_exn path)
+            [ ".wrapped_compat"
+            ; Path.basename path
+            ]
+        in
         let (base, _) = Path.split_extension path in
         { syntax = OCaml
         ; path = Path.extend_basename base ~suffix:".ml-gen"

src/module.mli

@@ -95,4 +95,4 @@ val set_pp : t -> (unit, string list) Build.t option -> t
 
 val to_sexp : t Sexp.To_sexp.t
 
-val deprecate : t -> t
+val wrapped_compat : t -> t

src/stdune/path.ml

@@ -943,3 +943,8 @@ module Internal = struct
     | In_source_tree l -> Local l
     | External l -> External l
 end
+
+module L = struct
+  (* TODO more efficient implementation *)
+  let relative t = List.fold_left ~init:t ~f:relative
+end

src/stdune/path.mli

@@ -169,3 +169,7 @@ val set_root : External.t -> unit
 module Internal : sig
   val raw_kind : t -> Kind.t
 end
+
+module L : sig
+  val relative : t -> string list -> t
+end