diff options
Diffstat (limited to 'nixpkgs/pkgs/test/haskell/incremental')
| -rw-r--r-- | nixpkgs/pkgs/test/haskell/incremental/default.nix | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/test/haskell/incremental/default.nix b/nixpkgs/pkgs/test/haskell/incremental/default.nix new file mode 100644 index 000000000000..4509939ba4f4 --- /dev/null +++ b/nixpkgs/pkgs/test/haskell/incremental/default.nix @@ -0,0 +1,35 @@ +# Demonstration of incremental builds for Haskell. Useful for speeding up CI. +# +# See: https://www.haskellforall.com/2022/12/nixpkgs-support-for-incremental-haskell.html +# See: https://felixspringer.xyz/homepage/blog/incrementalHaskellBuildsWithNix + +{ haskell, lib }: + +let + inherit (haskell.lib.compose) overrideCabal; + + # Incremental builds work with GHC >=9.4. + temporary = haskell.packages.ghc944.temporary; + + # This will do a full build of `temporary`, while writing the intermediate build products + # (compiled modules, etc.) to the `intermediates` output. + temporary-full-build-with-incremental-output = overrideCabal (drv: { + doInstallIntermediates = true; + enableSeparateIntermediatesOutput = true; + }) temporary; + + # This will do an incremental build of `temporary` by copying the previously + # compiled modules and intermediate build products into the source tree + # before running the build. + # + # GHC will then naturally pick up and reuse these products, making this build + # complete much more quickly than the previous one. + temporary-incremental-build = overrideCabal (drv: { + previousIntermediates = temporary-full-build-with-incremental-output.intermediates; + }) temporary; +in + temporary-incremental-build.overrideAttrs (old: { + meta = { + maintainers = lib.teams.mercury.members; + }; + }) |