Add darwin-version command

flake.nix

@@ -30,14 +30,17 @@
 
               system.checks.verifyNixPath = lib.mkDefault false;
 
-              system.darwinVersionSuffix = ".${self.shortRev or "dirty"}";
+              system.darwinVersionSuffix = ".${self.shortRev or self.dirtyShortRev or "dirty"}";
-              system.darwinRevision = lib.mkIf (self ? rev) self.rev;
+              system.darwinRevision = let
+                rev = self.rev or self.dirtyRev or null;
+              in
+                lib.mkIf (rev != null) rev;
             }) ];
           });
     };
 
     overlays.default = final: prev: {
-      inherit (prev.callPackage ./pkgs/nix-tools { }) darwin-rebuild darwin-option;
+      inherit (prev.callPackage ./pkgs/nix-tools { }) darwin-rebuild darwin-option darwin-version;
 
       darwin-uninstaller = prev.callPackage ./pkgs/darwin-uninstaller { nix-darwin = self; };
     };
@@ -76,7 +79,7 @@
     in {
       default = self.packages.${system}.darwin-rebuild;
 
-      inherit (pkgs) darwin-option darwin-rebuild darwin-uninstaller;
+      inherit (pkgs) darwin-option darwin-rebuild darwin-version darwin-uninstaller;
     });
   };
 }

modules/examples/flake/flake.nix

@@ -27,6 +27,9 @@
       programs.zsh.enable = true;  # default shell on catalina
       # programs.fish.enable = true;
 
+      # Set Git commit hash for darwin-version.
+      system.configurationRevision = self.rev or self.dirtyRev or null;
+
       # Used for backwards compatibility, please read the changelog before changing.
       # $ darwin-rebuild changelog
       system.stateVersion = 4;

modules/examples/lnl.nix

@@ -125,7 +125,7 @@
     set -g pane-border-style fg=black
     set -g status-bg black
     set -g status-fg white
-    set -g status-right '#[fg=white]#(id -un)@#(hostname)   #(cat /run/current-system/darwin-version)'
+    set -g status-right '#[fg=white]#(id -un)@#(hostname)   #(jq --raw-output '.darwinLabel' /run/current-system/darwin-version.json)'
   '';
 
   environment.etc."nix/user-sandbox.sb".text = ''

modules/nix/nix-darwin.nix

@@ -7,7 +7,7 @@ let
     nixPackage = config.nix.package;
   };
 
-  inherit (nix-tools) darwin-option darwin-rebuild;
+  inherit (nix-tools) darwin-option darwin-rebuild darwin-version;
 in
 
 {
@@ -17,10 +17,11 @@ in
       [ # Include nix-tools by default
         darwin-option
         darwin-rebuild
+        darwin-version
       ];
 
     system.build = {
-      inherit darwin-option darwin-rebuild;
+      inherit darwin-option darwin-rebuild darwin-version;
     };
 
   };

modules/system/default.nix

@@ -96,6 +96,12 @@ in
       activationUserScript = cfg.activationScripts.userScript.text;
       inherit (cfg) darwinLabel;
 
+      darwinVersionJson = (pkgs.formats.json {}).generate "darwin-version.json" (
+        filterAttrs (k: v: v != null) {
+          inherit (config.system) darwinRevision nixpkgsRevision configurationRevision darwinLabel;
+        }
+      );
+
       buildCommand = ''
         mkdir $out
 
@@ -129,7 +135,7 @@ in
 
         echo -n "$systemConfig" > $out/systemConfig
 
-        echo -n "$darwinLabel" > $out/darwin-version
+        ln -s $darwinVersionJson $out/darwin-version.json
         echo -n "$system" > $out/system
 
         ${cfg.systemBuilderCommands}

modules/system/version.nix

@@ -108,6 +108,12 @@ in
         else lib.trivial.revisionWithDefault null;
       description = lib.mdDoc "The nixpkgs git revision from which this configuration was built.";
     };
+
+    system.configurationRevision = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      description = lib.mdDoc "The Git revision of the top-level flake from which this configuration was built.";
+    };
   };
 
   config = {

pkgs/nix-tools/darwin-rebuild.sh

@@ -8,12 +8,11 @@ showSyntax() {
   echo "darwin-rebuild [--help] {edit | switch | activate | build | check | changelog}" >&2
   echo "               [--list-generations] [{--profile-name | -p} name] [--rollback]" >&2
   echo "               [{--switch-generation | -G} generation] [--verbose...] [-v...]" >&2
-  echo "               [-Q] [{--max-jobs | -j} number] [--cores number] [--dry-run]" >&1
+  echo "               [-Q] [{--max-jobs | -j} number] [--cores number] [--dry-run]" >&2
   echo "               [--keep-going] [-k] [--keep-failed] [-K] [--fallback] [--show-trace]" >&2
   echo "               [-I path] [--option name value] [--arg name value] [--argstr name value]" >&2
-  echo "               [--flake flake] [--update-input input flake] [--impure] [--recreate-lock-file]"
+  echo "               [--flake flake] [--update-input input flake] [--impure] [--recreate-lock-file]" >&2
   echo "               [--no-update-lock-file] [--refresh] ..." >&2
-  exec man darwin-rebuild
   exit 1
 }
 

pkgs/nix-tools/darwin-version.sh

@@ -0,0 +1,50 @@
+#! @shell@
+set -e
+set -o pipefail
+export PATH=@path@:$PATH
+
+showSyntax() {
+  echo "darwin-version [--help|--darwin-revision|--nixpkgs-revision|--configuration-revision|--json]" >&2
+}
+
+case "$1" in
+  --help)
+    showSyntax
+    ;;
+  --darwin-revision)
+    revision="$(jq --raw-output '.darwinRevision // "null"' < /run/current-system/darwin-version.json)"
+    if [[ "$revision" == "null" ]]; then
+      echo "$0: nix-darwin commit hash is unknown" >&2
+      exit 1
+    fi
+    echo "$revision"
+    ;;
+  --nixpkgs-revision)
+    revision="$(jq --raw-output '.nixpkgsRevision // "null"' < /run/current-system/darwin-version.json)"
+    if [[ "$revision" == "null" ]]; then
+      echo "$0: Nixpkgs commit hash is unknown" >&2
+      exit 1
+    fi
+    echo "$revision"
+    ;;
+  --configuration-revision)
+    revision="$(jq --raw-output '.configurationRevision // "null"' < /run/current-system/darwin-version.json)"
+    if [[ "$revision" == "null" ]]; then
+      echo "$0: configuration commit hash is unknown" >&2
+      exit 1
+    fi
+    echo "$revision"
+    ;;
+  --json)
+    cat /run/current-system/darwin-version.json
+    ;;
+  *)
+    label="$(jq --raw-output '.darwinLabel // "null"' < /run/current-system/darwin-version.json)"
+    if [[ "$label" == "null" ]]; then
+      showSyntax
+      exit 1
+    fi
+    echo "$label"
+    ;;
+esac
+

pkgs/nix-tools/default.nix

@@ -35,4 +35,11 @@ in
       inherit (stdenv) shell;
     }
     ./darwin-rebuild.sh;
+
+  darwin-version = writeProgram "darwin-version"
+    {
+      inherit (stdenv) shell;
+      path = lib.makeBinPath [ jq ];
+    }
+    ./darwin-version.sh;
 }