Comment # 4 on bug 1185500 from Michael Andres

Rpm issued neither error not any note on the screen. 

  # rpm --showrc| grep _topdir
  ...
  -13: _topdir    %{expand:%%global _topdir %{lua:if posix.access(rpm.expand("%
  {_usrsrc}/packages"), "w") then print "%{_usrsrc}/packages" else print 
  "%{getenv:HOME}/rpmbuild" end} 

But according to it's configuration rpm silently installed the packages to
~root/rpmbuild. Probably the same on your system.