Hello,

I'd like to know how ghc-pkg searches package databases and how the command-line flags affect the search.

My model of ghc-pkg was that it builds a list of package databases and then searches them starting from the head. I'd like to work with a sandboxed local package database. Looking at what ghc-pkg list prints, I can infer what database list it's using:

ghc-pkg list: [user-db, global-db]

ghc-pkg list --global: [global-db]

ghc-pkg list --global --package-conf=$HOME/sandbox/package.conf.d: [sandbox-db, global-db]

However, even though ghc-pkg doesn't show my user database, it still reports broken packages that are in my user database. So ghc-pkg isn't really scanning packages according to this database list. What is it doing?