In Ring Build Negative value is allow in <part_power> parameter

[Adeeb khan]

When executing swift-ring-builder command by passing negative value for <part_power> parameter, use case is executed successfully. When user rebalance the ring it does throw error "TypeError: integer argument expected, got float" . This happens because <part_power> is used to calculate number of partitions (2^<part_power>). When <part_power> is negative, number of partitions are calculated as float value which is incorrect.
Steps:
1.Build a ring
swift-ring-builder account.builder create -10 2 1 <<< There should be an error here >>>
2.Add device to it.
swift-ring-builder account.builder add --region 1 --zone 1 --ip 10.0.2.15 --port 6202 --device sda1 --weight 100
swift-ring-builder account.builder add --region 1 --zone 1 --ip 10.0.2.15 --port 6202 --device loop0 --weight 100
3.Rebalance the ring.
swift-ring-builder account.builder rebalance

Error message:
Traceback (most recent call last):
  File "/usr/bin/swift-ring-builder", line 24, in <module>
    sys.exit(main())
  File "/usr/lib/python2.7/site-packages/swift/cli/ringbuilder.py", line 1287, in main
    getattr(Commands, command, Commands.unknown)()
  File "/usr/lib/python2.7/site-packages/swift/cli/ringbuilder.py", line 859, in rebalance
    parts, balance, removed_devs = builder.rebalance(seed=get_seed(3))
  File "/usr/lib/python2.7/site-packages/swift/common/ring/builder.py", line 454, in rebalance
    self._last_part_moves = array('B', itertools.repeat(0, self.parts))
TypeError: integer argument expected, got float

Error is displayed after step 3 but error should be displayed after executing step 1.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/swift 2.31.1 release.