`(dirs ..` with paths of depth ≥ 2 are just ignored

[smondet]

I have vendors/dune containing:

(dirs project1/src/lib2 project2/src/lib42)

And dune (2.9.1) just ignores them (cannot find those libraries).

I'd expect either:

• that it just works (it's nice to be able to vendor libraries¹ without modifying nor adding dune files in their subtrees/submodules)
• or that it throws a decent error message (which is what the data_only_dirs stanza does: it says "Error: only immediate sub-directories may be specified.")

(¹); I know about (vendored_dirs ..) but I want @check and @fmt to still work on the vendored libraries)

• Version of dune (output of dune --version): 2.9.1
• Version of ocaml (output of ocamlc --version): 4.12.0
• Operating system (distribution and version): ubuntu-like

[nojb]

I think you should be able to do what you want by using (subdir ...):

(subdir project1 (subdir src (dirs lib2)))
(subdir project2 (subdir src (dirs lib42)))

but I agree it is not very ergonomic at the moment.