Ambiguity between package target and component target should resolve in favour of the package

[michaelpj]

Describe the bug
haskell-language-server has a cabal package of that name, which contains an executable of the same name.

That means that the haskell-language-server target is ambiguous between:

1. The package target
2. The component target for lib:haskell-language-server
3. The component target for exe:haskell-language-server

As a result, cabal says:

Error: cabal: Ambiguous target 'haskell-language-server'. It could be:
exe:haskell-language-server (component)
lib:haskell-language-server (component)

Somehow this doesn't bite if the executable isn't present, even though there is still an ambiguity between 1 and 2.

To Reproduce

Check out https://github.com/haskell/haskell-language-server and run cabal build haskell-language-server.

Expected behavior

I think the package target should always win if it is ambiguous with a component target. You can always disambiguate in favour of the component target, but there is no other way to select the package target (and hence to build all components in the package).

System information

• cabal-3.10

[michaelpj]

Turns out that pkg:foo is also a valid target!

[gbaz]

Should this become a ticket for documenting target syntax better?

[michaelpj]

So I still think that the current behaviour is a little weird, in particular the fact that ambiguity between the package target and the library target is okay, but not more than that.

Target syntax is otherwise documented okay, and I think just needs and addition for pkg:foo.