Get rid of compatibility symlinks for Dune directories

Signed-off-by: Jeremie Dimino <jeremie@dimino.org>

src/compilation_context.ml

@@ -37,6 +37,7 @@ type t =
   { super_context        : Super_context.t
   ; scope                : Scope.t
   ; dir                  : Path.t
+  ; dir_kind             : File_tree.Dune_file.Kind.t
   ; obj_dir              : Path.t
   ; modules              : Module.t Module.Name.Map.t
   ; alias_module         : Module.t option
@@ -50,6 +51,7 @@ type t =
 let super_context        t = t.super_context
 let scope                t = t.scope
 let dir                  t = t.dir
+let dir_kind             t = t.dir_kind
 let obj_dir              t = t.obj_dir
 let modules              t = t.modules
 let alias_module         t = t.alias_module
@@ -59,12 +61,13 @@ let requires             t = t.requires
 let includes             t = t.includes
 let preprocessing        t = t.preprocessing
 
-let create ~super_context ~scope ~dir ?(obj_dir=dir) ~modules ?alias_module
-      ?lib_interface_module ~flags ~requires
-      ?(preprocessing=Preprocessing.dummy) () =
+let create ~super_context ~scope ~dir ?(dir_kind=File_tree.Dune_file.Kind.Dune)
+      ?(obj_dir=dir) ~modules ?alias_module ?lib_interface_module ~flags
+      ~requires ?(preprocessing=Preprocessing.dummy) () =
   { super_context
   ; scope
   ; dir
+  ; dir_kind
   ; obj_dir
   ; modules
   ; alias_module

src/compilation_context.mli

@@ -16,6 +16,7 @@ val create
   :  super_context         : Super_context.t
   -> scope                 : Scope.t
   -> dir                   : Path.t
+  -> ?dir_kind             : File_tree.Dune_file.Kind.t
   -> ?obj_dir              : Path.t
   -> modules               : Module.t Module.Name.Map.t
   -> ?alias_module         : Module.t
@@ -32,6 +33,7 @@ val for_alias_module : t -> t
 val super_context        : t -> Super_context.t
 val scope                : t -> Scope.t
 val dir                  : t -> Path.t
+val dir_kind             : t -> File_tree.Dune_file.Kind.t
 val obj_dir              : t -> Path.t
 val modules              : t -> Module.t Module.Name.Map.t
 val alias_module         : t -> Module.t option

src/gen_rules.ml

@@ -569,6 +569,7 @@ module Gen(P : Install_rules.Params) = struct
         ~super_context:sctx
         ~scope
         ~dir
+        ~dir_kind
         ~obj_dir
         ~modules
         ?alias_module
@@ -874,6 +875,7 @@ module Gen(P : Install_rules.Params) = struct
         ~super_context:sctx
         ~scope
         ~dir
+        ~dir_kind
         ~obj_dir
         ~modules
         ~flags

src/module_compilation.ml

@@ -74,7 +74,7 @@ let build_cm cctx ?sandbox ?(dynlink=true) ~dep_graphs ~cm_kind (m : Module.t) =
           (fn :: other_targets, A "-bin-annot")
       in
       let hidden_targets = List.map other_targets ~f:(Target.file obj_dir) in
-      if obj_dir <> dir then begin
+      if CC.dir_kind cctx = Jbuild && obj_dir <> dir then begin
         (* Symlink the object files in the original directory for
            backward compatibility *)
         let old_dst = Module.cm_file_unsafe m ~obj_dir:dir cm_kind in

test/blackbox-tests/test-cases/ocamldep-multi-stanzas/run.t

@@ -8,10 +8,17 @@
   each module cannot appear in more than one "modules" field - it must belong
   to a single library or executable.
   This warning will become an error in the future.
-  Multiple rules generated for _build/default/lib$ext_obj:
-  - <internal location>
-  - <internal location>
-  [1]
+      ocamldep lib.ml.d
+        ocamlc .lib.objs/lib.{cmi,cmo,cmt}
+      ocamlopt .lib.objs/lib.{cmx,o}
+      ocamlopt lib.{a,cmxa}
+      ocamldep test.ml.d
+        ocamlc .test.eobjs/lib.{cmi,cmo,cmt}
+      ocamlopt .test.eobjs/lib.{cmx,o}
+        ocamlc .test.eobjs/test.{cmi,cmo,cmt}
+      ocamlopt .test.eobjs/test.{cmx,o}
+      ocamlopt test.exe
+  foo bar
 
   $ dune build src/a.cma --debug-dep --display short
   File "src/dune", line 1, characters 0-0: