No output from building oz

The weird thing is that ,while nix-env -f . -i oz does a lot of work,but after building the output path seems empty.

ls -a $(nix path-info -f . oz)
./  ../

You’re derivation doesn’t seem right. The hash of fetchFromGitHub is empty and there’s no modSha256.
Please have a look at other go modules and look how they work.

Also your command wouldn’t work. What are you trying to see?
When you’re derivation is working you can list the contained files with ls -l $(nix-build -A oz).

I uploaded an old version by error.Now there is the new version
It does compile,but again

ls $(nix-build -A oz)
./  ../