davean
It seems the code was written using an IORef which caused MonadIO to be required when simply Monad would have done. I modified it to be based on StateT and...
There exists no inputs for which it satisfies its type signature. Simply deleting it until it is actually implemented would save people some debugging time.
Git requires trees on disk to be sorted by https://github.com/git/git/blob/master/builtin/mktree.c#L34-L40 and https://github.com/git/git/blob/bca181109d6f054d525c71a84963bbdc1f0c40bf/read-cache.c#L385-L402
if your git repo uses pack-refs, hit can technically handle this. It makes it very round about and unclean though. I believe the only function to directly handle both cases...
Version 0.6.3 of hit introduces new types (EntName) and changes the type signature of functions in a non-comparable way. This breaks dependent packages with policy-based version bounds.