From 5c967b158fe7b43e4386a9bc1c54a450dcfd7417 Mon Sep 17 00:00:00 2001
From: Antonio Nuno Monteiro <anmonteiro@gmail.com>
Date: Sat, 25 Feb 2023 18:23:33 -0800
Subject: [PATCH] fix: always start from lib_subdir when installing module
 sources

Signed-off-by: Antonio Nuno Monteiro <anmonteiro@gmail.com>
---
 src/dune_rules/install_rules.ml                          | 9 +++++++++
 .../test-cases/install/dune-package-source-path.t        | 4 ++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/dune_rules/install_rules.ml b/src/dune_rules/install_rules.ml
index 3fee9c9cd8e..aee581eb059 100644
--- a/src/dune_rules/install_rules.ml
+++ b/src/dune_rules/install_rules.ml
@@ -155,6 +155,15 @@ end = struct
                   in
                   (sub_dir, dst)
               in
+              let sub_dir =
+                match sub_dir with
+                | None -> lib_subdir
+                | Some subdir ->
+                  Some
+                    (match lib_subdir with
+                    | None -> subdir
+                    | Some lib_subdir -> Filename.concat lib_subdir subdir)
+              in
               make_entry ?sub_dir Lib source ?dst))
     in
     let { Lib_config.has_native; ext_obj; _ } = lib_config in
diff --git a/test/blackbox-tests/test-cases/install/dune-package-source-path.t b/test/blackbox-tests/test-cases/install/dune-package-source-path.t
index 88db5067c1d..15f9109bac3 100644
--- a/test/blackbox-tests/test-cases/install/dune-package-source-path.t
+++ b/test/blackbox-tests/test-cases/install/dune-package-source-path.t
@@ -70,8 +70,6 @@ Test paths on public libraries with `.` are correct
   $ cat b/_build/default/b.install
   lib: [
     "_build/install/default/lib/b/META"
-    "_build/install/default/lib/b/child/bar.ml" {"child/bar.ml"}
-    "_build/install/default/lib/b/child/child.ml" {"child/child.ml"}
     "_build/install/default/lib/b/dune-package"
     "_build/install/default/lib/b/sub/b.a" {"sub/b.a"}
     "_build/install/default/lib/b/sub/b.cma" {"sub/b.cma"}
@@ -89,6 +87,8 @@ Test paths on public libraries with `.` are correct
     "_build/install/default/lib/b/sub/b__Foo.cmi" {"sub/b__Foo.cmi"}
     "_build/install/default/lib/b/sub/b__Foo.cmt" {"sub/b__Foo.cmt"}
     "_build/install/default/lib/b/sub/b__Foo.cmx" {"sub/b__Foo.cmx"}
+    "_build/install/default/lib/b/sub/child/bar.ml" {"sub/child/bar.ml"}
+    "_build/install/default/lib/b/sub/child/child.ml" {"sub/child/child.ml"}
     "_build/install/default/lib/b/sub/foo.ml" {"sub/foo.ml"}
   ]
   libexec: [