我正在尝试通过以下方式获得 ns-3-dev 版本：
[root@localhost ns-3-allinone]# ./download.py -n ns-3-dev
#
# Get NS-3
#
Cloning ns-3 branch
=> hg clone http://code.nsnam.org/ns-3-dev ns-3-dev
requesting all changes
adding changesets
adding manifests
transaction abort!
rollback completed
abort: consistency error in delta!
Traceback (most recent call last):
File "./download.py", line 316, in
sys.exit(main())
File "./download.py", line 261, in main
ns3_dir = get_ns3(options.ns3_branch)
File "./download.py", line 26, in get_ns3
run_command(['hg', 'clone', ns3_branch_url, ns3_dir])
File "/mercurial/mercurial-2.5.1/mercurial/repos/ns-3-allinone/util.py", line 24, in run_command
raise CommandError("Command %r exited with code %i" % (argv, retval))
util.CommandError: Command ['hg', 'clone', 'http://code.nsnam.org/ns-3-dev', 'ns-3-dev'] exited with code 255
但是，我可以克隆目录 ns-3-allinone：
[root@localhost repos]# hg clone http://code.nsnam.org/ns-3-allinone
destination directory: ns-3-allinone
requesting all changes
adding changesets
adding manifests
adding file changes
added 55 changesets with 78 changes to 7 files
updating to branch default
7 files updated, 0 files merged, 0 files removed, 0 files unresolved
为什么我无法获得 ns-3-dev 的副本？