# `haskell.nix` is infrastructure for building Haskell packages with Nix

`haskell.nix` can automatically translate your Cabal or Stack project and
its dependencies into Nix code.

## Documentation

- [Introduction](https://input-output-hk.github.io/haskell.nix/index.html)
- [Getting Started](https://input-output-hk.github.io/haskell.nix/tutorials/getting-started)
- [Troubleshooting](https://input-output-hk.github.io/haskell.nix/troubleshooting)
- Explore the documentation from there to find further topics.

## Help! Something isn't working

The #1 problem that people have when using `haskell.nix` is that they find themselves building GHC.
This should not happen, but you *must* follow the `haskell.nix` setup instructions properly to avoid it.
If you find this happening to you, please check that you have followed the 
[getting started instructions](https://input-output-hk.github.io/haskell.nix/tutorials/getting-started#setting-up-the-binary-cache) and
consult the corresponding [troubleshooting section](https://input-output-hk.github.io/haskell.nix/troubleshooting#why-am-i-building-ghc).

The troubleshooting documentation also contains some help for other common issues. If you're still stuck open an issue.

## Compiler CI status

`haskell.nix` publishes prebuilt GHCs (and boot libraries) to two binary caches:

- **`cache.iog.io`** only holds the GHC versions currently in use by IOG's own
  projects, so it does not cover every compiler `haskell.nix` supports.
- **`cache.zw3rk.com`** holds *all* the compiler versions currently tested in
  `haskell.nix` CI — including cross-compilers — so configuring it as an extra
  substituter is the surest way to avoid building GHC yourself.

The table below is generated automatically from the latest `master` builds on
[`ci.zw3rk.com`](https://ci.zw3rk.com/jobset/input-output-hk-haskell-nix/master)
and shows the build status of GHC itself (the `roots.ghc` job) for each
compiler and platform. A ✅ means that compiler/platform is built and cached
for the current `master` (a build only counts once it is part of the latest
evaluation, so a green never reflects a stale build).

Legend: ✅ built & cached · ⚠️ dependency failed · ❌ failed · ⚪ aborted/cancelled · 🕓 building

<!-- CI-STATUS:START -->
<!-- This table is generated by scripts/update-ci-status.sh from the latest
     master builds on ci.zw3rk.com. Do not edit it by hand. -->

| Nixpkgs | Host → Target | ghc914-sh | ghc967 | ghc984 | ghc9103 | ghc9124 | ghc9141 | ghc9141llvm |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| unstable | `x86_64-linux` | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| unstable | `x86_64-linux` → static | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | · |
| unstable | `x86_64-linux` → musl64 | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| unstable | `x86_64-linux` → musl32 | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | · |
| unstable | `x86_64-linux` → aarch64 | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| unstable | `x86_64-linux` → aarch64-musl | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| unstable | `x86_64-linux` → android/aarch64 | ✅ | · | · | · | ✅ | ✅ | ✅ |
| unstable | `x86_64-linux` → android/armv7a | ✅ | · | · | · | ✅ | ✅ | ✅ |
| unstable | `x86_64-linux` → javascript | ✅ | ✅ | ✅ | · | ✅ | ✅ | · |
| unstable | `x86_64-linux` → wasm | ✅ | · | · | · | ✅ | ✅ | · |
| unstable | `x86_64-linux` → windows/mingwW64 | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | · |
| unstable | `x86_64-linux` → windows/ucrt64 | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | · |
| unstable | `aarch64-darwin` | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| unstable | `aarch64-darwin` → musl64 | ✅ | · | · | · | · | ✅ | · |
| unstable | `aarch64-darwin` → aarch64-musl | ✅ | · | · | · | · | ✅ | · |
| unstable | `aarch64-darwin` → javascript | ✅ | ✅ | ✅ | · | ✅ | ✅ | · |
| unstable | `aarch64-darwin` → wasm | ✅ | · | · | · | ✅ | ✅ | · |
<!-- CI-STATUS:END -->

## Related repos

The `haskell.nix` repository contains the runtime system for building
Haskell packages in Nix. It depends on other repos, which are:

- [`hackage.nix`](https://github.com/input-output-hk/hackage.nix) — the latest contents of the [Hackage](https://hackage.haskell.org/) databases, converted to Nix expressions.

- [`stackage.nix`](https://github.com/input-output-hk/stackage.nix) — all of the [Stackage](https://www.stackage.org/) snapshots, converted to Nix expressions.

> [!NOTE]
> For commercial support, please don't hesitate to reach out at devx@iohk.io