go: could not create module cache: mkdir /sbuild-nonexistent: permission denied
To make this go away, the package must Build-Depend on dh-golang.
However, that does not seem to be enough. The way subpackages are fetched or not during build is not very clear to me. How did you put together the 2.9.0 source package?
-richard.
OpenPGP_signature
Description: OpenPGP digital signature
