Updates following PR review comments

src/driver/odoc_driver.ml

@@ -589,14 +589,14 @@ let run mode
         let extra_paths = Voodoo.extra_paths odoc_dir in
         (all, extra_paths, actions)
     | Dune { path } ->
-        (Dune_style.of_dune_build path, Util.StringMap.(empty, empty), All)
+        (Dune_style.of_dune_build path, Voodoo.empty_extra_paths, All)
     | Opam { packages; packages_dir } ->
         let libs = if packages = [] then Ocamlfind.all () else packages in
         let libs =
           List.map Ocamlfind.sub_libraries libs
           |> List.fold_left Util.StringSet.union Util.StringSet.empty
         in
-        (Packages.of_libs ~packages_dir libs, Util.StringMap.(empty, empty), All)
+        (Packages.of_libs ~packages_dir libs, Voodoo.empty_extra_paths, All)
   in
 
   let virtual_check =

src/driver/odoc_units_of.ml

@@ -1,11 +1,13 @@
 open Odoc_unit
 
-let packages ~dirs ~extra_paths:(extra_pkg_paths, extra_libs_paths)
-    (pkgs : Packages.t list) : t list =
+let packages ~dirs ~extra_paths (pkgs : Packages.t list) : t list =
   let { odoc_dir; odocl_dir; index_dir; mld_dir = _ } = dirs in
   (* [module_of_hash] Maps a hash to the corresponding [Package.t], library name and
      [Packages.modulety]. [lib_dirs] maps a library name to the odoc dir containing its
      odoc files. *)
+  let extra_libs_paths = extra_paths.Voodoo.libs in
+  let extra_pkg_paths = extra_paths.Voodoo.pkgs in
+
   let module_of_hash, lib_dirs =
     let open Packages in
     let h = Util.StringMap.empty in

src/driver/odoc_units_of.mli

@@ -1,7 +1,4 @@
 open Odoc_unit
 
 val packages :
-  dirs:dirs ->
-  extra_paths:Fpath.t Util.StringMap.t * Fpath.t Util.StringMap.t ->
-  Packages.t list ->
-  t list
+  dirs:dirs -> extra_paths:Voodoo.extra_paths -> Packages.t list -> t list

src/driver/voodoo.ml

@@ -12,6 +12,9 @@ type pkg = {
 
 let prep_path = ref "prep"
 
+(* We mark the paths that contain compiled units for both packages and libraries
+   by dropping in a marker file. The contents of the file is unimportant, as we
+   can determine which package or library we're looking at simply by its path. *)
 let lib_marker = ".odoc_lib_marker"
 let pkg_marker = ".odoc_pkg_marker"
 
@@ -249,7 +252,7 @@ let of_voodoo pkg_name ~blessed =
   in
   match contents with
   | Error _ -> Util.StringMap.empty
-  | Ok c ->
+  | Ok c -> (
       let sorted = List.sort (fun p1 p2 -> Fpath.compare p1 p2) c in
       let last, packages =
         List.fold_left
@@ -276,40 +279,58 @@ let of_voodoo pkg_name ~blessed =
           (None, []) sorted
       in
       let packages = List.filter_map (fun x -> x) (last :: packages) in
-      let packages = List.map process_package packages in
-      let pkg = List.hd packages in
-      Logs.debug (fun m -> m "Package: %a\n%!" Packages.pp pkg);
-      Util.StringMap.singleton pkg_name (List.hd packages)
+      match packages with
+      | [ package ] ->
+          let package = process_package package in
+          Logs.debug (fun m -> m "Package: %a\n%!" Packages.pp package);
+          Util.StringMap.singleton pkg_name package
+      | [] ->
+          Logs.err (fun m -> m "No package found for %s" pkg_name);
+          Util.StringMap.empty
+      | _ ->
+          Logs.err (fun m -> m "Multiple packages found for %s" pkg_name);
+          Util.StringMap.empty)
+
+type extra_paths = {
+  pkgs : Fpath.t Util.StringMap.t;
+  libs : Fpath.t Util.StringMap.t;
+}
+
+let empty_extra_paths =
+  { pkgs = Util.StringMap.empty; libs = Util.StringMap.empty }
 
 let extra_paths compile_dir =
   let contents =
     Bos.OS.Dir.fold_contents ~dotfiles:true
       (fun p acc -> p :: acc)
       [] compile_dir
   in
-  match contents with
-  | Error _ -> (Util.StringMap.empty, Util.StringMap.empty)
-  | Ok c ->
-      List.fold_left
-        (fun (pkgs, libs) abs_path ->
-          let path = Fpath.rem_prefix compile_dir abs_path |> Option.get in
-          match Fpath.segs path with
-          | [ "p"; _pkg; _version; libname; l ] when l = lib_marker ->
-              Logs.debug (fun m -> m "Found lib marker: %a" Fpath.pp path);
-              (pkgs, Util.StringMap.add libname (Fpath.parent path) libs)
-          | [ "p"; pkg; _version; l ] when l = pkg_marker ->
-              Logs.debug (fun m -> m "Found pkg marker: %a" Fpath.pp path);
-              (Util.StringMap.add pkg (Fpath.parent path) pkgs, libs)
-          | [ "u"; _universe; _pkg; _version; libname; l ] when l = lib_marker
-            ->
-              Logs.debug (fun m -> m "Found lib marker: %a" Fpath.pp path);
-              (pkgs, Util.StringMap.add libname (Fpath.parent path) libs)
-          | [ "u"; _universe; pkg; _version; l ] when l = pkg_marker ->
-              Logs.debug (fun m -> m "Found pkg marker: %a" Fpath.pp path);
-              (Util.StringMap.add pkg (Fpath.parent path) pkgs, libs)
-          | _ -> (pkgs, libs))
-        (Util.StringMap.empty, Util.StringMap.empty)
-        c
+  let pkgs, libs =
+    match contents with
+    | Error _ -> (Util.StringMap.empty, Util.StringMap.empty)
+    | Ok c ->
+        List.fold_left
+          (fun (pkgs, libs) abs_path ->
+            let path = Fpath.rem_prefix compile_dir abs_path |> Option.get in
+            match Fpath.segs path with
+            | [ "p"; _pkg; _version; libname; l ] when l = lib_marker ->
+                Logs.debug (fun m -> m "Found lib marker: %a" Fpath.pp path);
+                (pkgs, Util.StringMap.add libname (Fpath.parent path) libs)
+            | [ "p"; pkg; _version; l ] when l = pkg_marker ->
+                Logs.debug (fun m -> m "Found pkg marker: %a" Fpath.pp path);
+                (Util.StringMap.add pkg (Fpath.parent path) pkgs, libs)
+            | [ "u"; _universe; _pkg; _version; libname; l ] when l = lib_marker
+              ->
+                Logs.debug (fun m -> m "Found lib marker: %a" Fpath.pp path);
+                (pkgs, Util.StringMap.add libname (Fpath.parent path) libs)
+            | [ "u"; _universe; pkg; _version; l ] when l = pkg_marker ->
+                Logs.debug (fun m -> m "Found pkg marker: %a" Fpath.pp path);
+                (Util.StringMap.add pkg (Fpath.parent path) pkgs, libs)
+            | _ -> (pkgs, libs))
+          (Util.StringMap.empty, Util.StringMap.empty)
+          c
+  in
+  { pkgs; libs }
 
 let write_lib_markers odoc_dir pkgs =
   let write file str =

src/driver/voodoo.mli

@@ -3,6 +3,21 @@ val find_universe_and_version :
 
 val of_voodoo : string -> blessed:bool -> Packages.set
 
-val extra_paths : Fpath.t -> Fpath.t Util.StringMap.t * Fpath.t Util.StringMap.t
+type extra_paths = {
+  pkgs : Fpath.t Util.StringMap.t;
+  libs : Fpath.t Util.StringMap.t;
+}
+
+val empty_extra_paths : extra_paths
+(** When [odoc_driver] is not running in voodoo mode, this value can be passed to 
+    {!Odoc_units_of.packages} *)
+
+val extra_paths : Fpath.t -> extra_paths
+(** [extra_paths odoc_dir] returns the paths to packages and libraries that have previously
+    been compiled by odoc_driver running in voodoo mode. In order to find these, 
+    the previous invocation of odoc_driver will need to have written marker files by
+    calling {!write_lib_markers} *)
 
 val write_lib_markers : Fpath.t -> Packages.t Util.StringMap.t -> unit
+(** [write_lib_markers odoc_dir pkgs] writes marker files to show the locations of the
+    compilation units associated with packages and libraries in [pkgs]. *)