This nix expression downloads a recent artefact from gitlab.haskell.org and enters a nix shell with the artefact available. It should work on x86_64-linux, i386-linux, aarch64-linux and x86_64-darwin.

One simple way to use it is:

nix run -f https://github.com/mpickering/ghc-artefact-nix/archive/master.tar.gz ghcHEAD

This will enter a shell where the most up to date artefact built for the master branch is available to use.

You can also specify additional packages to be available from the normal nixpkgs set. It's often useful to have cabal also available.

nix run -f https://github.com/mpickering/ghc-artefact-nix/archive/master.tar.gz ghcHEAD cabal-install

Finally, you can specify the two options fork and branch in order to download an artefact for a contributors branch in order to test a merge request. For example in order to test !180 which is on the fork called brprice and from branch wip/doc-pragma-fixes I can run:

nix run -f https://github.com/mpickering/ghc-artefact-nix/archive/master.tar.gz \
      --argstr fork brprice \
      --argstr branch wip/doc-pragma-fixes \
      ghcHEAD cabal-install

and then test the compiler locally.

ghc-head-from script

The most convenient way to get into the shell is to use the ghc-head-from script which has three modes of operation.

1. Specifying a MR by its number as the first argument fetches artefacts from that MR.
2. Specifying a link to a (fedora27/33) bindist uses that bindist.
3. Omitting the argument means we fetch the artefact from ghc/master.

This is an example of fetching the artefacts for MR 180.

> ghc-head-from 180
Fetching from MR: doc: user's guide pragma fixes
Fetching artefact from brprice/wip/doc-pragma-fixes
...

or fetching an artefact from HEAD.

> ghc-head-from
Fetching artefact from ghc/master
...

If you use NUR then you can access the script via the attribute nur.repos.mpickering.ghc-head-from.

nix-shell -p nur.repos.mpickering.ghc-head-from

Nesting shells doesn't work very well in Nix so it's probably better to add the attribute to your configuration.nix file and install it globally.

Releases

In addition to the ability to grab binary distributions from GitLab, this repository also includes releases.nix, which packages a number of official release tarballs. For instance, one could drop into a shell with 8.10.1-alpha2 available with,

nix run -f releases.nix ghc_8_10_1_alpha2