Independent subset of cabal packages set

Question

Given a set of cabal packages, is there a way to automatically calculate subset of independent packages? In other words, subset of packages that will be sufficient to install them all.

For [network,parsec] the answer is [network] because it network depends on parsec.

For [network,containers] the answer is [network,containers] because:

• network does not depend on containers
• all networks dependencies not depends on containers
• containers does not depend on network
• all containerss dependencies not depends on network

It's not hard to find the answer for 2 packages. What is really interesting is to find out independent set for [containers, directory, filepath, lens, xml, http-conduit, regex-posix, monad-control, unordered-containers, glib, hashable, hspec, split, aeson, attoparsec, stm, QuickCheck].

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From answer I expect some function based on cabal library like ∷ [Packages] → IO [Packages].

Answer 1

Cabal is moving to a more NPM-like model, which will make dependency resolution much simpler. Each installed package will keep a local copy of its dependencies, trading a little disk space for the headache of installing multiple global packages with mutually exclusive package versioning demands.

Under this model, the subset of packages required to install a set of packages == that set. Though one may be a dependency of the other, each installed copy will keep its own local copy of its dependencies, so Cabal won't consider the dependency installed that way any more.