diff --git a/pkgs/build-support/docker/default.nix b/pkgs/build-support/docker/default.nix
index ea464ebea18c..146de2b7b3d8 100644
--- a/pkgs/build-support/docker/default.nix
+++ b/pkgs/build-support/docker/default.nix
@@ -523,7 +523,7 @@ rec {
     runCommand "${baseNameOf name}.tar${compress.ext}"
       {
         inherit (stream) imageName;
-        passthru = { inherit (stream) imageTag; };
+        passthru = { inherit (stream) imageTag; inherit stream; };
         nativeBuildInputs = compress.nativeInputs;
       } "${stream} | ${compress.compress} > $out"
   );