Change @doc to only build public docs

Private docs can still be built using the new @doc-private alias

src/build_system.ml

@@ -225,7 +225,7 @@ module Alias0 = struct
   let dep t = Build.path (stamp_file t)
 
   let is_standard = function
-    | "runtest" | "install" | "doc" | "lint" -> true
+    | "runtest" | "install" | "doc" | "doc-private" | "lint" -> true
     | _ -> false
 
   open Build.O
@@ -272,11 +272,12 @@ module Alias0 = struct
              It is not defined in %s or any of its descendants."
           name (Path.to_string_maybe_quoted src_dir)
 
-  let default = make "DEFAULT"
-  let runtest = make "runtest"
-  let install = make "install"
-  let doc     = make "doc"
-  let lint    = make "lint"
+  let default     = make "DEFAULT"
+  let runtest     = make "runtest"
+  let install     = make "install"
+  let doc         = make "doc"
+  let private_doc = make "doc-private"
+  let lint        = make "lint"
 end
 
 module Dir_status = struct

src/build_system.mli

@@ -100,11 +100,12 @@ module Alias : sig
 
   val fully_qualified_name : t -> Path.t
 
-  val default : dir:Path.t -> t
-  val runtest : dir:Path.t -> t
-  val install : dir:Path.t -> t
-  val doc     : dir:Path.t -> t
-  val lint    : dir:Path.t -> t
+  val default     : dir:Path.t -> t
+  val runtest     : dir:Path.t -> t
+  val install     : dir:Path.t -> t
+  val doc         : dir:Path.t -> t
+  val private_doc : dir:Path.t -> t
+  val lint        : dir:Path.t -> t
 
   (** Return the underlying stamp file *)
   val stamp_file : t -> Path.t

src/odoc.ml

@@ -200,7 +200,11 @@ let setup_library_rules sctx (lib : Library.t) ~dir ~modules ~mld_files
       to_html sctx m odoc_file ~doc_dir ~odoc ~dir ~includes ~lib)
   in
   let doc_root = SC.Doc.root sctx in
-  SC.add_alias_deps sctx (Build_system.Alias.doc ~dir)
+  let alias =
+    match lib.public with
+    | None -> Build_system.Alias.private_doc ~dir
+    | Some _ -> Build_system.Alias.doc ~dir in
+  SC.add_alias_deps sctx alias
     (css_file ~doc_dir:doc_root
      :: toplevel_index ~doc_dir:doc_root
      :: html_files)
@@ -268,15 +272,17 @@ let gen_rules sctx ~dir:_ rest =
     setup_toplevel_index_rule sctx
   | lib :: _ ->
     let libs = SC.libs sctx in
-    let (lib, scope) =
+    let (lib, scope, alias) =
       match String.rsplit2 lib ~on:'@' with
-      | None -> (lib, Lib_db.external_scope libs)
-      | Some (lib, name) -> (lib, Lib_db.find_scope_by_name_exn libs ~name)
+      | None ->
+        (lib, Lib_db.external_scope libs, "doc")
+      | Some (lib, name) ->
+        (lib, Lib_db.find_scope_by_name_exn libs ~name, "doc-private")
     in
     let scope =
       { With_required_by.
         data = scope
-      ; required_by = [Alias (Path.of_string "doc")]
+      ; required_by = [Alias (Path.of_string alias)]
       } in
     let open Option.Infix in
     Option.iter (Lib_db.Scope.find scope lib >>= Lib.src_dir)

test/blackbox-tests/test-cases/multiple-private-libs/run.t

@@ -1,6 +1,6 @@
 This test checks that there is no clash when two private libraries have the same name
 
-  $ $JBUILDER build -j1 --display short --root . @doc
+  $ $JBUILDER build -j1 --display short --root . @doc-private
           odoc _doc/odoc.css
           odoc _doc/test@a/page-index.odoc
       ocamldep a/test.ml.d