Alternative dependencies do not work with `include_subdirs unqualified`

[toots]

This is a similar issue to #4381. It looks like any file used for alternative dependency need to be at the root even when using include_subdirs unqualified

#4381 does seem like a bug, but this one I'm less sure about given that select works with files and not module names. Could you post an example and how you expect Dune to behave?

[toots]

Dune file:

(include_subdirs unqualified)

(library
  (name optional)
  (modules optional_module)
  (libraries
    (select optional_module.ml from
      (foo -> optional_module.foo.ml)
      (-> optional_module.default.ml))))

Directory structure:

dune
src/
  optional_module.foo.ml
  optional_module.default.ml

I havent been able to find a way to make this work so far.

Have you tried:

(include_subdirs unqualified)

(library
  (name optional)
  (modules optional_module)
  (libraries
    (select optional_module.ml from
      (foo -> src/optional_module.foo.ml)
      (-> src/optional_module.default.ml))))

?

[toots]

Yes, it does not work.

Adding copy rules should provide a workaround until the bug is fixed:

(include_subdirs unqualified)

(library
  (name optional)
  (modules optional_module)
  (libraries
    (select optional_module.ml from
      (foo -> optional_module.foo.ml)
      (-> optional_module.default.ml))))

(copy_files src/optional_module.*.ml)

[toots]

Great, thanks!