Why does rpmbuild create an empty debug rpm file of a custom rpm containing scripts?

Issue

• The rpmbuild is creating a blank debuginfo rpm of a custom rpm as follows.

[root@localhost x86_64]# rpm -qp test-debuginfo-12.1.2-1.el6.x86_64.rpm 
test-debuginfo-12.1.2-1.el6.x86_64
[root@localhost x86_64]# rpm -qlp test-debuginfo-12.1.2-1.el6.x86_64.rpm 
(contains no files)

• For other rpms, it's creating debuginfo populated with files.

[root@localhost x86_64]# rpm -qlp tree-debuginfo-1.5.3-3.el6.x86_64.rpm 
/usr/lib/debug
/usr/lib/debug/.build-id
/usr/lib/debug/.build-id/b0
/usr/lib/debug/.build-id/b0/1c4c0a02052579c64bc94d370c7f7cd36603fd
/usr/lib/debug/.build-id/b0/1c4c0a02052579c64bc94d370c7f7cd36603fd.debug
/usr/lib/debug/usr
/usr/lib/debug/usr/bin
/usr/lib/debug/usr/bin/tree.debug
/usr/src/debug/tree-1.5.3
/usr/src/debug/tree-1.5.3/tree.c