Workspace rules (GHC binary distributions)

bindist_info_for_version

bindist_info_for_version(ctx, version)

Attributes

`ctx`	required
`version`	required

configure_python3_toolchain

configure_python3_toolchain(name, register)

Autoconfigure python3 toolchain for GHC bindist

rules_haskell requires Python 3 to build Haskell targets. Under Nix we use rules_nixpkgs’s nixpkgs_python_configure repository rule to use a nixpkgs provisioned Python toolchain. However, outside of Nix we have to rely on whatever Python toolchain is installed on the system.

Bazel provides @bazel_tools//tools/python:autodetecting_toolchain for this purpose. However, in its current form, that toolchain does not support Python toolchains installed outside of standard system paths such as /usr/bin:/bin:/usr/sbin. The reason is that the toolchain does not look for a Python interpreter in a repository rule. Instead it uses wrapper scripts that look for a Python interpreter in $PATH within the sandboxed build actions.

On MacOS, which, at the time of writing, only includes Python 2.7, users will want to install Python 3 in a non-system path, e.g. via homebrew or py_env. The auto detecting toolchain will not find this interpreter and builds will fail with the following error:

Error occurred while attempting to use the default Python toolchain (@rules_python//python:autodetecting_toolchain).
According to '/usr/bin/python -V', version is 'Python 2.7.10', but we need version 3. PATH is:

/usr/bin:/bin:/usr/sbin

Please ensure an interpreter with version 3 is available on this platform as 'python3' or 'python', or else register an appropriate Python toolchain as per the documentation for py_runtime_pair (https://github.com/bazelbuild/rules_python/blob/master/docs/python.md#py_runtime_pair).

Note that prior to Bazel 0.27, there was no check to ensure that the interpreter's version matched the version declared by the target (#4815). If your build worked prior to Bazel 0.27, and you're sure your targets do not require Python 3, you can opt out of this version check by using the non-strict autodetecting toolchain instead of the standard autodetecting toolchain. This can be done by passing the flag `--extra_toolchains=@rules_python//python:autodetecting_toolchain_nonstrict` on the command line or adding it to your bazelrc.

This function defins a custom auto detcting Python toolchain that looks for a Python 3 interpreter within a repository rule, so that Bazel’s sandboxing does not restrict the visible installation paths. It then registers an appropriate Python toolchain, so that build actions themselves can still be sandboxed.

Attributes

`name`	required A unique name for the repository.
`register`	optional; default is `True` Whether to register the toolchains (must be set to False if bzlmod is enabled)

ghc_bindist

ghc_bindist(name, version, target, compiler_flags, ghcopts, haddock_flags, repl_ghci_args,
            cabalopts, locale, register)

Create a new repository from binary distributions of GHC.

The repository exports two targets:

a bin filegroup containing all GHC commands,
a threaded-rts CC library.

These targets are unpacked from a binary distribution specific to your platform. Only the platforms that have a “binary package” on the GHC download page are supported.

Examples

In WORKSPACE file:

load("@rules_haskell//haskell:ghc_bindist.bzl", "ghc_bindist")

# This repository rule creates @ghc repository.
ghc_bindist(
  name    = "ghc",
  version = "8.2.2",
)

Attributes

`name`	required A unique name for the repository.
`version`	required The desired GHC version.
`target`	required
`compiler_flags`	optional; default is `None` see rules_haskell_toolchains
`ghcopts`	optional; default is `None` see rules_haskell_toolchains
`haddock_flags`	optional; default is `None` see rules_haskell_toolchains
`repl_ghci_args`	optional; default is `None` see rules_haskell_toolchains
`cabalopts`	optional; default is `None` see rules_haskell_toolchains
`locale`	optional; default is `None` see rules_haskell_toolchains
`register`	optional; default is `True` Whether to register the toolchains (must be set to False if bzlmod is enabled)

ghc_bindist_toolchain_declaration

ghc_bindist_toolchain_declaration(target, bindist_name, toolchain_name)

Attributes

`target`	required
`bindist_name`	required
`toolchain_name`	required

ghc_bindists_toolchain_declarations

ghc_bindists_toolchain_declarations(mctx, version)

Attributes

`mctx`	required
`version`	required

haskell_register_ghc_bindists

haskell_register_ghc_bindists(version, compiler_flags, ghcopts, haddock_flags, repl_ghci_args,
                              cabalopts, locale, register, targets)

See rules_haskell_toolchains.

Attributes

`version`	optional; default is `None` see rules_haskell_toolchains
`compiler_flags`	optional; default is `None` see rules_haskell_toolchains
`ghcopts`	optional; default is `None` see rules_haskell_toolchains
`haddock_flags`	optional; default is `None` see rules_haskell_toolchains
`repl_ghci_args`	optional; default is `None` see rules_haskell_toolchains
`cabalopts`	optional; default is `None` see rules_haskell_toolchains
`locale`	optional; default is `None` see rules_haskell_toolchains
`register`	optional; default is `True` Whether to register the toolchains (must be set to False if bzlmod is enabled)
`targets`	optional; default is `["darwin_amd64", "darwin_arm64", "linux_amd64", "linux_arm64", "windows_amd64"]` A list of target platforms to generate bindists for, e.g. `["linux_amd64", "windows_amd64"]` (default: all)