Fix merlin generation in presence of include_subdirs (#1083)

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

src/gen_rules.ml

@@ -671,7 +671,11 @@ module Gen(P : Install_rules.Params) = struct
       loop stanzas [] []
     in
     Option.iter (Merlin.merge_all merlins) ~f:(fun m ->
-      Merlin.add_rules sctx ~dir:ctx_dir ~scope ~dir_kind:kind
+      let more_src_dirs =
+        List.map (Dir_contents.dirs dir_contents) ~f:(fun dc ->
+          Path.drop_optional_build_context (Dir_contents.dir dc))
+      in
+      Merlin.add_rules sctx ~dir:ctx_dir ~more_src_dirs ~scope ~dir_kind:kind
         (Merlin.add_source_dir m src_dir));
     Utop.setup sctx ~dir:ctx_dir ~scope ~libs:(
       List.filter_map stanzas ~f:(function

src/merlin.ml

@@ -109,7 +109,8 @@ let ppx_flags sctx ~dir:_ ~scope ~dir_kind { preprocess; libname; _ } =
   end
   | Other -> []
 
-let dot_merlin sctx ~dir ~scope ~dir_kind ({ requires; flags; _ } as t) =
+let dot_merlin sctx ~dir ~more_src_dirs ~scope ~dir_kind
+      ({ requires; flags; _ } as t) =
   match Path.drop_build_context dir with
   | None -> ()
   | Some remaindir ->
@@ -137,6 +138,9 @@ let dot_merlin sctx ~dir ~scope ~dir_kind ({ requires; flags; _ } as t) =
                   |> Path.drop_optional_build_context)
               , Path.Set.add obj_dirs (Lib.obj_dir lib)))
         in
+        let src_dirs =
+          Path.Set.union src_dirs (Path.Set.of_list more_src_dirs)
+        in
         Dot_file.to_string
           ~remaindir
           ~ppx:(ppx_flags sctx ~dir ~scope ~dir_kind t)
@@ -162,6 +166,6 @@ let merge_all = function
   | [] -> None
   | init::ts -> Some (List.fold_left ~init ~f:merge_two ts)
 
-let add_rules sctx ~dir ~scope ~dir_kind merlin =
+let add_rules sctx ~dir ~more_src_dirs ~scope ~dir_kind merlin =
   if (SC.context sctx).merlin then
-    dot_merlin sctx ~dir ~scope ~dir_kind merlin
+    dot_merlin sctx ~dir ~more_src_dirs ~scope ~dir_kind merlin

src/merlin.mli

@@ -22,6 +22,7 @@ val merge_all : t list -> t option
 val add_rules
   : Super_context.t
   -> dir:Path.t
+  -> more_src_dirs:Path.t list
   -> scope:Scope.t
   -> dir_kind:File_tree.Dune_file.Kind.t
   -> t

test/blackbox-tests/test-cases/merlin-tests/dune-project

@@ -1 +1 @@
-(lang dune 1.0)
+(lang dune 1.1)

test/blackbox-tests/test-cases/merlin-tests/lib/dune

@@ -6,5 +6,7 @@
 
 (library
  (name bar)
- (modules ())
+ (modules file)
  (preprocess (pps fooppx)))
+
+(include_subdirs unqualified)

test/blackbox-tests/test-cases/merlin-tests/lib/subdir/file.ml

@@ -0,0 +1 @@
+let x = 42

test/blackbox-tests/test-cases/merlin-tests/run.t

@@ -26,6 +26,7 @@
   S $LIB_PREFIX/lib/findlib
   S $LIB_PREFIX/lib/ocaml
   S .
+  S subdir
   FLG -ppx '$PPX/fooppx@./ppx.exe --as-ppx --cookie '\''library-name="foo"'\'''
   FLG -open Foo -w -40 -open Bar -w -40