[hakari] [feature request]: only add workspace-hack crate as dependency to crate that need it

[cmtm]

cargo hakari manage-deps currently adds the workspace-hack crate to all crates in the workspace. This means that even crates that have no dependencies now get a dependency on the workspace-hack crate.

If I understand correctly, the workspace-hack only needs to be added to crates that directly depend on one of the crates in the workspace-hack crate's dependencies. More clearly, the workspace hack depends on a set of third party crates S. The manage-deps step only needs to add the workspace hack to crates that directly depend on at least one member of S.

The benefit of this change would be that it reduces the footprint of using hakari.

Thoughts?

[sunshowers]

Hi, thanks for the report! Sorry to have missed it earlier, I've been busy with other projects.

That's definitely an interesting idea. We don't do it automatically at the moment, but can you achieve it with traversal-excludes or final-excludes? Both of them should cause the crate to no longer be counted in cargo hakari manage-deps.

[sunshowers]

More clearly, the workspace hack depends on a set of third party crates S. The manage-deps step only needs to add the workspace hack to crates that directly depend on at least one member of S.

Hm, this is not quite true as you've specified it -- if a package has third-party dependencies for which there are transitive dependencies in S, it could need the workspace-hack for feature unification as well. This is pretty common with crates like syn -- few crates directly depend on it, but in large projects, many crates transitively depend on it.