disko2: Add flake-output and package

This allows running `nix run .#disko2` for testing

flake.nix

@@ -32,6 +32,8 @@
         in
         {
           disko = pkgs.callPackage ./package.nix { diskoVersion = version; };
+          disko2 = pkgs.callPackage ./package-disko2.nix { diskoVersion = version; };
+
           # alias to make `nix run` more convenient
           disko-install = self.packages.${system}.disko.overrideAttrs (_old: {
             name = "disko-install";

lib/eval-config.nu

@@ -1,8 +1,10 @@
+use libexec-dir.nu
+
 alias nix = ^nix --extra-experimental-features nix-command --extra-experimental-features flakes
 alias nix-eval-expr = nix eval --impure --json --expr
 
 def eval-config [args: record]: nothing -> record {
-    let eval_config_nix = $env.FILE_PWD + "/lib/eval-config.nix"
+    let eval_config_nix = (libexec-dir) + "/lib/eval-config.nix"
 
     do { nix-eval-expr $"import ($eval_config_nix) \(builtins.fromJSON ''($args | to json -r)'')" }
     | complete

lib/libexec-dir.nu

@@ -0,0 +1,5 @@
+export def main []: nothing -> path {
+    # $env.FILE_PWD contains the file of the script (disko.nu), not this module
+    let libexec_dir = $env.FILE_PWD
+    $libexec_dir
+}

package-disko2.nix

@@ -0,0 +1,38 @@
+{ stdenvNoCC, makeWrapper, lib, path, nix, coreutils, nixos-install-tools, binlore, diskoVersion }:
+
+let
+  shareDir = "share/disko2";
+  self = stdenvNoCC.mkDerivation (finalAttrs: {
+    name = "disko2";
+    src = ./.;
+    nativeBuildInputs = [
+      makeWrapper
+    ];
+    installPhase = ''
+      mkdir -p $out/bin $out/${shareDir}
+      cp -r default.nix disk-deactivate lib $out/${shareDir}
+      cp disko2 $out/bin/
+
+      sed -ie "s|libexec_dir = .*|libexec_dir = '$out/${shareDir}'|" $out/${shareDir}/lib/libexec-dir.nu
+      sed -ie "s|use lib|use \"$out/${shareDir}/lib\"|" $out/bin/disko2
+      chmod 755 "$out/bin/disko2"
+      wrapProgram "$out/bin/disko2" \
+        --set DISKO_VERSION "${diskoVersion}" \
+        --prefix PATH : ${lib.makeBinPath [ nix coreutils nixos-install-tools ]} \
+        --prefix NIX_PATH : "nixpkgs=${path}"
+    '';
+    # Otherwise resholve thinks that disko and disko-install might be able to execute their arguments
+    passthru.binlore.out = binlore.synthesize self ''
+      execer cannot bin/.disko2-wrapped
+    '';
+    meta = with lib; {
+      description = "Format disks with nix-config";
+      homepage = "https://github.com/nix-community/disko";
+      license = licenses.mit;
+      maintainers = with maintainers; [ lassulus ];
+      platforms = platforms.linux;
+      mainProgram = finalAttrs.name;
+    };
+  });
+in
+self