Introduce genCrossPlatformNixActions command.

This command generates GitHub workflows on Ubuntu and macOS.

.nix/shellHook.sh

@@ -165,6 +165,17 @@ genNixActions (){
 }
 addNixCommand genNixActions
 
+genCrossPlatformNixActions (){
+  mkdir -p $currentDir/.github/workflows/
+  for t in $bundles; do
+    for p in "ubuntu" "macos"; do
+      echo "generating $currentDir/.github/workflows/nix-action-$t-$p.yml"
+      nix-shell --arg do-nothing true --argstr bundle $t --argstr ci-platform "$p-latest" --run "ppNixAction > $currentDir/.github/workflows/nix-action-$t-$p.yml"
+    done
+  done
+}
+addNixCommand genCrossPlatformNixActions
+
 initNixConfig (){
   Orig=$toolboxDir/template-config.nix
   F=$configDir/config.nix;

README.md

@@ -90,14 +90,15 @@ When you run `nix-shell`, you get an environment with a few available commands:
 - `nixEnv`: displays the list of Nix store locations for all the available packages.
 - `fetchCoqOverlay`: fetch a derivation file from nixpkgs that you may then edit locally to override a package.
 - `cachedMake`: compile the project by reusing build outputs cached (generally thanks to Cachix).
-- `genNixActions`: generates GitHub one actions file per bundle, for testing dependencies and reverse depndencies.
+- `genNixActions`: generates GitHub one actions file per bundle, for testing dependencies and reverse dependencies.
+- `genCrossPlatformNixActions`: duplicate generated workflows to run on both Ubuntu and macOS (useful when macOS users want to get cached artifacts as well).
 
 These three commands update the nixpkgs version to use (will create or override `.nix/nixpkgs.nix`):
 - `updateNixpkgsUnstable`: update to the latest nixpkgs-unstable.
 - `updateNixpkgsMaster`: update to the head of `master` of nixpkgs.
 - `updateNixpkgs`: update to the specified owner and ref.
 
-After one of these three commands, you should leave and re-enter `nix-shell` if you want the update to be taken into account (e.g., before calling `genNixActions`).
+After one of these three commands, you should leave and re-enter `nix-shell` if you want the update to be taken into account.
 
 ## Arguments accepted by `nix-shell`
 
@@ -114,7 +115,7 @@ To test a PR on nixpkgs that modifies the `coqPackages` set, clone this reposito
 
 ```
 nix-shell --arg do-nothing true --run "updateNixpkgs <pr_owner> <pr_branch>"
-nix-shell --arg do-nothing true --run "genNixActions"
+nix-shell --arg do-nothing true --run "genCrossPlatformNixActions"
 ```
 
 Then, open a draft PR with the generated changes here.
@@ -123,5 +124,5 @@ Once the PR on nixpkgs has been merged, you can transform the draft PR into one
 
 ```
 nix-shell --arg do-nothing true --run "updateNixpkgsMaster"
-nix-shell --arg do-nothing true --run "genNixActions"
+nix-shell --arg do-nothing true --run "genCrossPlatformNixActions"
 ```

action.nix

@@ -78,13 +78,13 @@ with builtins; with lib; let
     run  = "NIXPKGS_ALLOW_UNFREE=1 nix-build --no-out-link --argstr bundle \"${bundlestr}\" --argstr job \"${job}\"";
   };
 
-  mkJob = { job, jobs ? [], bundles ? [], deps ? {}, cachix ? {}, suffix ? false }:
+  mkJob = { job, jobs ? [], bundles ? [], deps ? {}, cachix ? {}, ci-platform, suffix ? false }:
     let
       suffixStr = optionalString (suffix && isString bundles) "-${bundles}";
       jdeps = deps.${job} or [];
     in {
     "${job}${suffixStr}" = rec {
-      runs-on = "ubuntu-latest";
+      runs-on = if ci-platform == null then "ubuntu-latest" else ci-platform;
       needs = map (j: "${j}${suffixStr}") (filter (j: elem j jobs) jdeps);
       steps = [ stepCommitToTest stepCheckout stepCachixInstall ]
               ++ (stepCachixUseAll cachix)
@@ -94,11 +94,11 @@ with builtins; with lib; let
     } // (optionalAttrs (isList bundles) {strategy.matrix.bundle = bundles;});
   };
 
-  mkJobs = { jobs ? [], bundles ? [], deps ? {}, cachix ? {}, suffix ? false }@args:
+  mkJobs = { jobs ? [], bundles ? [], deps ? {}, cachix ? {}, ci-platform, suffix ? false }@args:
     foldl (action: job: action // (mkJob ({ inherit job; } // args))) {} jobs;
 
-  mkActionFromJobs = { actionJobs, bundles ? [] }: {
-    name = "Nix CI for bundle ${toString bundles}";
+  mkActionFromJobs = { actionJobs, bundles ? [], ci-platform }: {
+    name = "Nix CI for bundle ${toString bundles}${if ci-platform == null then "" else " on platform ${ci-platform}"}";
     on = {
       push.branches = [ "master" ];
       pull_request.paths = [ ".github/workflows/**" ];
@@ -107,7 +107,7 @@ with builtins; with lib; let
     jobs = actionJobs;
   };
 
-  mkAction = { jobs ? [], bundles ? [], deps ? {}, cachix ? {} }@args:
-    mkActionFromJobs {inherit bundles; actionJobs = mkJobs args; };
+  mkAction = { jobs ? [], bundles ? [], deps ? {}, cachix ? {}, ci-platform ? null }@args:
+    mkActionFromJobs {inherit bundles ci-platform; actionJobs = mkJobs args; };
 
 in { inherit mkJob mkJobs mkAction; }

config-parser-1.0.0/default.nix

@@ -11,6 +11,7 @@ with builtins;
   override ? {},
   ocaml-override ? {},
   global-override ? {},
+  ci-platform,
   lib,
 }@initial:
 with lib;
@@ -59,6 +60,7 @@ in with config; let
     inherit (import ../action.nix { inherit lib; }) mkJobs mkAction;
     action = mkAction {
       inherit (config) cachix;
+      inherit ci-platform;
       bundles = bundleName;
       jobs = let
           jdeps = genAttrs ci.mains (n: genCI.pkgsRevDepsSet.${n} or {});

default.nix

@@ -17,6 +17,7 @@ in
   coq-overlays-dir ? get-path src "coq-overlays",
   ocaml-overlays-dir ? get-path src "ocaml-overlays",
   ci-matrix ? false,
+  ci-platform ? null,
   config ? {},
   override ? {},
   ocaml-override ? {},
@@ -44,6 +45,7 @@ let
           // { diag = f: x: f x x; };
     inherit overlays-dir coq-overlays-dir ocaml-overlays-dir;
     inherit global-override override ocaml-override;
+    inherit ci-platform;
   };
   my-throw = x: throw "Coq nix toolbox error: ${x}";
 in