generic error: found empty hash, assuming sha256-aaa...

[lucasew]

I am working on https://github.com/NixOS/nixpkgs/pull/279936 on Nixpkgs.

Ofborg is failing with that error and I don't know what to try to solve it.

Maybe the reason of the failure is that I am using the src of one package in other packages but AFAIK there is no better way to make them point to the same src.

Why does it happen and how can I fix it?