@hackage / cabal-plan

This package provides a library (see Cabal.Plan) for decoding plan.json files as well as the simple tool cabal-plan for extracting and pretty printing the information contained in the plan.json file.

plan.json files are generated by cabal's Nix-style local builds and contain detailed information about the build/install plan computed by the cabal solver.

cabal-plan utility

The cabal-plan executable (enabled via the exe cabal flag) provides various operations:

info

Show basic report of dependency tree

show

Dump PlanJson data-structure via Show instance

tred

Show dependency tree as a graph

diff

Diff two install plans

list-bins

List all binaries

list-bin

List single binary (useful for scripting, e.g. cabal list-bin exe:cabal-plan)

fingerprint

Print SHA256 sums of dependencies' source tarballs and cabal files

dot

Generate graph of dependencies in .dot format

topo

Print plan topologically sorted

license-report

Generate license report for a component (only available when built with license-report flag enabled); see report example for cabal-plan (Pandoc rendered HTML)

See also "New things in Haskell package QA" Blogpost for a description of the topo and dot operations as well as how to enable tab-completion.