Version from compile time nix

flake.nix

@@ -12,7 +12,11 @@
     let pkgs = nixpkgs.legacyPackages.${system};
         hp = nixpkgs.legacyPackages.${system}.haskellPackages.override (old: {
       overrides = pkgs.lib.composeExtensions (old.overrides or (_: _: {})) (f: p: {
-        wallabag-tagger = f.callPackage ./. {};
+        wallabag-tagger = pkgs.haskell.lib.overrideCabal (f.callPackage ./. {}) (_: {
+          preBuild = ''
+            export COMMIT="${self.rev or "unknown"}"
+          '';
+        });
       });
     });
     in rec {