enable Mac build in GitHub Action

[peterbecich]

#1193

nix flake check restricted to current system in latest Nix version, so there should be no error "Mac required but I am a Linux", or vice versa

[peterbecich]

Would someone with a Mac try nix flake check and tell me if this error occurs? Thanks

https://github.com/haskell/hackage-server/actions/runs/5307816226/jobs/9606696192#step:6:27

error: Package ‘glibc-2.37-8’ in /nix/store/22z4n4mxs2vz3l3lg41dz3mgnq1d4wxs-source/pkgs/development/libraries/glibc/default.nix:166 
is not available on the requested hostPlatform:

        hostPlatform.config = "x86_64-apple-darwin"
         package.meta.platforms = [
           "aarch64-linux"
           "armv5tel-linux"
           "armv6l-linux"
           "armv7a-linux"
           "armv7l-linux"
           "i686-linux"
           "m68k-linux"
           "microblaze-linux"
           "microblazeel-linux"
           "mipsel-linux"
           "mips64el-linux"
           "powerpc64-linux"
           "powerpc64le-linux"
           "riscv32-linux"
           "riscv64-linux"
           "s390-linux"
           "s390x-linux"
           "x86_64-linux"
         ]
         package.meta.badPlatforms = [ ]
       , refusing to evaluate.

[peterbecich]

I have asked if this might be in haskell-flake: srid/haskell-flake#172

[srid]

@peterbecich This should do it,

--- a/flake.nix
+++ b/flake.nix
@@ -117,7 +117,7 @@
             with pkgs;
             [ cabal-install
               ghc
-
+            ] ++ lib.optionals pkgs.stdenv.isLinux [
               glibc
               icu67
               zlib

[srid]

Or better (to re-use haskell-flake's devShell):

diff --git a/flake.nix b/flake.nix
index cbac13ae..59f149f3 100644
--- a/flake.nix
+++ b/flake.nix
@@ -113,11 +113,11 @@
         # devShells.default =
         #   config.mission-control.installToDevShell self'.devShells.main;
         devShells.default = pkgs.mkShell {
+          inputsFrom = [
+            config.haskellProjects.main.outputs.devShell
+          ];
           buildInputs =
-            with pkgs;
-            [ cabal-install
-              ghc
-
+            with pkgs; lib.optionals pkgs.stdenv.isLinux [
               glibc
               icu67
               zlib

[peterbecich]

Awesome, thank you @srid . I am going to merge this now so it caches, which should use fewer GitHub Actions minutes, and I will apply that fix in a subsequent PR