Expected Behavior

When uninstalling a package containing man pages, dune should accept that the manpage directories can be non-empty after removing the manpages from the project being uninstalled.

Actual Behavior

When uninstalling a package containing man pages, dune sometimes errors out, with a message stating that some directories, such as <prefix>/man/man1, are non-empty and that the user should manually delete it. This is a problem since such directories are shared by all tools being installed in a prefix, and thus there are perfectly good reasons for such directories to not be empty (even if during installation dune had to create some of these directories).

Reproduction

• PR with a reproducing test: (test) Add testcase for uninstalling a package with manpages #5541

Specifications

• Version of dune (output of dune --version): 3.0.3
• Version of ocaml (output of ocamlc --version): 4.13.1
• Operating system (distribution and version): Archlinux

Additional information

This issue makes the CI of alt-ergo fail (see e.g. https://github.com/OCamlPro/alt-ergo/runs/5816456115?check_suite_focus=true ).