[merlin] Also load configuration when sources are in build dir (ocaml…

…#4274)

* Drop build context when present to handle files in `_build` dir
* Add test using `dune ocaml-merlin` for files in build dir

Signed-off-by: Ulysse Gérard <[email protected]>

CHANGES.md

@@ -44,6 +44,22 @@ Unreleased
 - Have `dune` communicate the location of the standard library directory to
   `merlin` (#4211, fixes #4188, @nojb)
 
+- Add support for instrumentation dependencies (#4210, fixes #3983, @nojb)
+
+- Workaround incorrect exception raised by `Unix.utimes` (OCaml PR#8857) in
+  `Path.touch` on Windows. This fixes dune cache in direct mode on Windows.
+  (#4223, @dra27)
+
+- Cleanup temporary files after running `$ dune exec`. (#4260, fixes #4243,
+  @rgrinberg)
+
+- Add a new subcommand `dune ocaml dump-dot-merlin` that prints a mix of all the
+  merlin configuration of a directory (defaulting to the current directory) in
+  the Merlin configuration syntax. (#4250, @voodoos)
+
+- `dune ocaml-merlin` is now able to provide configuration for source files in
+  the `_build` directory. (#4274, @voodoos)
+
 2.8.2 (21/01/2021)
 ------------------
 

src/dune_rules/merlin_server.ml

@@ -59,7 +59,11 @@ let to_local file_path =
   (* Then we make the path relative to [Path.root] (and not [Path.initial_cwd]) *)
   match make_relative_to_root abs_file_path with
   | Some path -> (
-    try Ok (Path.Local.of_string path)
+    try
+      let path = Path.of_string path in
+      (* If dune ocaml-merlin is called from within the build dir we must remove
+         the build context *)
+      Ok (Path.drop_optional_build_context path |> Path.local_part)
     with User_error.E mess -> User_message.to_string mess |> error )
   | None ->
     Printf.sprintf "Path %S is not in dune workspace (%S)." file_path
@@ -112,7 +116,9 @@ let load_merlin_file local_path file =
           Path.Local.parent path )
   in
   let default =
-    Printf.sprintf "No config found for file %S. Try calling `dune build`." file
+    Printf.sprintf
+      "No config found for file %S in %S. Try calling `dune build`." file
+      (Path.Local.to_string local_path)
     |> Merlin_conf.make_error
   in
   Option.value (find_closest local_path) ~default

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

@@ -2,7 +2,7 @@
   $ dune ocaml-merlin  <<EOF
   > (4:File${#FILE}:$FILE)
   > EOF
-  ((5:ERROR61:No config found for file "main.ml". Try calling `dune build`.))
+  ((5:ERROR68:No config found for file "main.ml" in ".". Try calling `dune build`.))
 
   $ dune build @check
 
@@ -41,3 +41,16 @@ Test of an valid invalid module name
   > (4:File${#FILE}:$FILE)
   > EOF
   ((?:STDLIB?:OPAM_PREFIX/lib/ocaml)(?:EXCLUDE_QUERY_DIR)(?:B?:$TESTCASE_ROOT/_build/default/.not-a-module-name.eobjs/byte)(?:S?:$TESTCASE_ROOT)(?:FLG(?:-w?:@1..3@5..28@30..39@43@46..47@49..57@61..62-?:-strict-sequence?:-strict-formats?:-short-paths?:-keep-locs?:-w?:-24)))
+
+Dune should also provide configuration when the file is in the build folder
+  $ FILE=$PWD/_build/default/lib3.ml
+  $ dune ocaml-merlin <<EOF | sed -E "s/[[:digit:]]+:/\?:/g" | sed 's#'$(opam config var prefix)'#OPAM_PREFIX#'
+  > (4:File${#FILE}:$FILE)
+  > EOF
+  ((?:STDLIB?:OPAM_PREFIX/lib/ocaml)(?:EXCLUDE_QUERY_DIR)(?:B?:$TESTCASE_ROOT/_build/default/.mylib.objs/byte)(?:B?:$TESTCASE_ROOT/_build/default/.mylib3.objs/byte)(?:S?:$TESTCASE_ROOT)(?:FLG(?:-open?:Mylib?:-w?:@1..3@5..28@30..39@43@46..47@49..57@61..62-?:-strict-sequence?:-strict-formats?:-short-paths?:-keep-locs)))
+
+  $ FILE=_build/default/lib3.ml
+  $ dune ocaml-merlin <<EOF | sed -E "s/[[:digit:]]+:/\?:/g" | sed 's#'$(opam config var prefix)'#OPAM_PREFIX#'
+  > (4:File${#FILE}:$FILE)
+  > EOF
+  ((?:STDLIB?:OPAM_PREFIX/lib/ocaml)(?:EXCLUDE_QUERY_DIR)(?:B?:$TESTCASE_ROOT/_build/default/.mylib.objs/byte)(?:B?:$TESTCASE_ROOT/_build/default/.mylib3.objs/byte)(?:S?:$TESTCASE_ROOT)(?:FLG(?:-open?:Mylib?:-w?:@1..3@5..28@30..39@43@46..47@49..57@61..62-?:-strict-sequence?:-strict-formats?:-short-paths?:-keep-locs)))