Install hpack with Homebrew, apt, Nix

Project links

• Homepage
• Upstream docs
• Package manager page

Commands and aliases

• hpack

Project history

Simon Hengel's hpack appeared on Hackage in April 2015 with version 0.1.0. The project README describes it as a modern alternative to the Cabal package format, guided by three principles: infer obvious information, give users control when needed, and avoid repeating metadata.

hpack developed alongside Cabal rather than replacing it. The executable reads `package.yaml` and renders a `.cabal` file, while its changelog tracks years of Cabal compatibility work: SPDX license handling, generated module behavior, internal libraries, `build-tool-depends`, Cabal version inference, and support for newer GHC and Cabal releases.

Adoption history

The README documents native `package.yaml` support in Stack and cabal2nix, while Hackage lists reverse dependencies including stack, pantry, cabal2nix, stack2cabal, stack-lib, and stackage2nix. That places hpack in the machinery around Haskell project templates, Stackage snapshots, and Nix conversion.

Homebrew, Hackage, Stackage, and Linux distribution packaging make hpack available both as a Haskell library/program and as a standalone CLI. Its adoption is tied to `package.yaml` becoming a common Haskell project file, especially in Stack-oriented projects.

How it is used

Users write package metadata in `package.yaml`. Stack can consume that file directly, cabal2nix supports it natively, and other workflows can run `hpack` to generate the `.cabal` file before building.

hpack also supports practical package-authoring features such as defaults files, globbing, verbatim Cabal fields, generated module controls, common fields, conditionals, executables, tests, benchmarks, and dependency syntax intended to keep package descriptions maintainable.

Why package nerds care

hpack is important because it sits at the contested boundary between package metadata as a human-maintained source file and package metadata as generated build-tool input. Package nerds care about that boundary: generated `.cabal` files can reduce repetition, but they also introduce questions about source-of-truth, reproducibility, diffs, and downstream tooling.

Its long changelog is also a miniature history of Haskell packaging pressure points, from SPDX licenses and Cabal version syntax to generated modules and compatibility with Stack, Stackage, Nix, and newer Cabal releases.

Timeline

• 2015: Hackage records hpack 0.1.0 uploaded by Simon Hengel.
• 0.18.0: The changelog adds command-line input-file handling and executable shorthand.
• 0.29.0: The changelog adds Cabal 2.1/2.2-related rendering and SPDX license handling.
• 0.36.0: The changelog changes `Paths_` module inference for package specs using spec-version 0.36.0 or later.
• 2026: Hackage records hpack 0.39.6, adding top-level `codeberg` support.

Related projects

• Cabal is the package format and build-tool ecosystem that hpack generates into.
• Stack has built-in support for hpack's `package.yaml` workflow.
• cabal2nix supports `package.yaml` natively, connecting hpack to Nix packaging workflows.
• Stackage-related tools such as pantry, stack2cabal, stack-lib, and stackage2nix appear in Hackage reverse-dependency metadata.

Sources

• https://docs.haskellstack.org/en/stable/topics/package_description/
• https://formulae.brew.sh/formula/hpack
• https://github.com/sol/hpack
• https://github.com/sol/hpack/blob/main/CHANGELOG.md
• https://hackage.haskell.org/package/hpack
• https://hackage.haskell.org/package/hpack-0.1.0
• https://hackage.haskell.org/package/hpack-0.39.6