Description of problem:

# mock -r fedora-rawhide-i386 init
You are attempting to run "mock" which requires administrative
privileges, but more information is needed in order to do so.
Authenticating as "root"
Password: 
INFO: mock.py version 0.9.12 starting...
State Changed: init plugins
State Changed: start
State Changed: lock buildroot
State Changed: clean
State Changed: init
ERROR: Could not create dir /var/lib/mock//fedora-rawhide-i386/result. Error: [Errno 13] Permission denied: '/var/lib/mock//fedora-rawhide-i386/result'
Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/mock/util.py", line 62, in mkdirIfAbsent
    os.makedirs(dirName)
  File "/usr/lib/python2.5/os.py", line 171, in makedirs
    mkdir(name, mode)
OSError: [Errno 13] Permission denied: '/var/lib/mock//fedora-rawhide-i386/result'
ERROR: Could not create dir /var/lib/mock//fedora-rawhide-i386/result. Error: [Errno 13] Permission denied: '/var/lib/mock//fedora-rawhide-i386/result'

Version-Release number of selected component (if applicable):
mock-0.9.12-1.fc10.noarch

How reproducible:
Always.

Steps to Reproduce:
1. make sure user is not in group "mock"
2. run "mock -r fedora-rawhide-i386 init"

Actual results:
c.f. above.

Expected results:
Function. IMO, mock should either work without any complaint or to refuse working with a clear messages.

That said, IMO this behavior is multiply broken:
* this interactive "login as root" is silly. mock should abort with a proper error message if something (permissions) doesn't fit.
* letting users run into tracebacks is dirty coding (== bug). mock should abort with a proper error message, if something doesn't fit.
* As mock requires special privileges and is not "runable by arbitrary users", mock should be moved to /usr/sbin.