diff --git a/pkgs/top-level/make-tarball.nix b/pkgs/top-level/make-tarball.nix
index dbe96bd096f8..ea975a9b6fcc 100644
--- a/pkgs/top-level/make-tarball.nix
+++ b/pkgs/top-level/make-tarball.nix
@@ -64,7 +64,7 @@ pkgs.releaseTools.sourceTarball {
     echo "generating packages.json"
     mkdir -p $out/nix-support
     echo -n '{"version":2,"packages":' > tmp
-    nix-env -f . -I nixpkgs=$src -qa --meta --json --arg config 'import ${./packages-config.nix}' "''${opts[@]}" >> tmp
+    nix-env -f . -I nixpkgs=$src -qa --meta --json --show-trace --arg config 'import ${./packages-config.nix}' "''${opts[@]}" >> tmp
     echo -n '}' >> tmp
     packages=$out/packages.json.br
     < tmp sed "s|$(pwd)/||g" | jq -c | brotli -9 > $packages