Merge pull request #292760 from PigeonF/dockertools-build-layered-compressor

dockerTools: Fix changing compression method for `buildLayeredImage`

nixos/tests/docker-tools.nix

···
             "docker load --input='${examples.bashUncompressed}'",
             "docker rmi ${examples.bashUncompressed.imageName}",
         )
+        docker.succeed(
+            "docker load --input='${examples.bashLayeredUncompressed}'",
+            "docker rmi ${examples.bashLayeredUncompressed.imageName}",
+        )
+        docker.succeed(
+            "docker load --input='${examples.bashLayeredZstdCompressed}'",
+            "docker rmi ${examples.bashLayeredZstdCompressed.imageName}",
+        )
 
     with subtest(
         "Check if the nix store is correctly initialized by listing "

pkgs/build-support/docker/default.nix

···
 
   buildLayeredImage = lib.makeOverridable ({ name, compressor ? "gz", ... }@args:
     let
-      stream = streamLayeredImage args;
+      stream = streamLayeredImage (builtins.removeAttrs args ["compressor"]);
       compress = compressorForImage compressor name;
     in
     runCommand "${baseNameOf name}.tar${compress.ext}"
···
   # Wrapper around streamNixShellImage to build an image from the result
   buildNixShellImage = { drv, compressor ? "gz", ... }@args:
     let
-      stream = streamNixShellImage args;
+      stream = streamNixShellImage (builtins.removeAttrs args ["compressor"]);
       compress = compressorForImage compressor drv.name;
     in
     runCommand "${drv.name}-env.tar${compress.ext}"

pkgs/build-support/docker/examples.nix

···
     contents = pkgs.bashInteractive;
   };
 
-  # buildImage without explicit tag
+  # buildLayeredImage without compression
+  bashLayeredUncompressed = pkgs.dockerTools.buildLayeredImage {
+    name = "bash-layered-uncompressed";
+    tag = "latest";
+    compressor = "none";
+    contents = pkgs.bashInteractive;
+  };
+
+  # buildLayeredImage with zstd compression
+  bashLayeredZstdCompressed = pkgs.dockerTools.buildLayeredImage {
+    name = "bash-layered-zstd";
+    tag = "latest";
+    compressor = "zstd";
+    contents = pkgs.bashInteractive;
+  };
+
+  # streamLayeredImage without explicit tag
   bashNoTagStreamLayered = pkgs.dockerTools.streamLayeredImage {
     name = "bash-no-tag-stream-layered";
     contents = pkgs.bashInteractive;