This module is based on GHC's utilsghc-pkgMain.hs at commit f66fc15f2e6849125074bcfeb44334a663323ca6 (see GHC merge request !11142), with:

• changeDBDir' does not perform an effective ghc-pkg recache,
• the cache is not used,
• consistency checks are not performed,
• use Stack program name,
• use Stack.Prelude rather than Prelude,
• use RIO env monad,
• use well-typed representations of paths from the path package,
• add pretty messages and exceptions,
• redundant code deleted,
• Hlint applied, and
• explicit import lists.

The version of the ghc-pkg executable supplied with GHCs published before 28 August 2023 does not efficiently bulk unregister. This module exports a function that does efficiently bulk unregister.