packdiff

Usage:

packdiff diff <package-name> <rev1> <package-name> <rev2>

Limitations:

Packdiff uses the hoogle file created by haddock to generate and compare the difference between multiple versions of a package

1. The API for modules in the other-modules sections is not generated or compared.
2. The re-exported module is just considered a re-exported module. The API of the re-exported module isn't merged with the module that re-exports it.

The 2nd limitation might end up falsely reporting a diff even if the diff does not exist. In our use-case where we have manual intervention this isn't a problem and does the job well.