OK. When I do git-buildpackage (no arguments) in the directory I have been working in, I get
dpkg-buildpackage -rfakeroot -D -us -uc -i -I
dpkg-buildpackage: source package phyutility
dpkg-buildpackage: source version 2.6-1
dpkg-buildpackage: source distribution UNRELEASED
dpkg-source -i -I --before-build phyutility
dpkg-buildpackage: host architecture amd64
dpkg-checkbuilddeps: Unmet build dependencies: javahelper default-jdk libjebl2-java
dpkg-buildpackage: warning: build dependencies/conflicts unsatisfied; aborting
dpkg-buildpackage: warning: (Use -d flag to override.)
debuild: fatal error at line 1364:
dpkg-buildpackage -rfakeroot -D -us -uc -i -I failed
gbp:error: Couldn't run 'debuild -i -I': debuild -i -I returned 29
Is this the error you were getting? I am looking at the git-buildpackage documentation but am having a little difficulty determining when the arguments are necessary (despite the fact that I understand arguments).