Mercurial (hg) 更新错误，中止：没有这样的文件或目录

我无法在我的机器上更新 Mercurial 存储库。当我进行更新时出现以下错误hg up --traceback:

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/mercurial/dispatch.py", line 87, in _runcatch
    return _dispatch(req)
  File "/usr/lib/python2.7/dist-packages/mercurial/dispatch.py", line 679, in _dispatch
    cmdpats, cmdoptions)
  File "/usr/lib/python2.7/dist-packages/mercurial/dispatch.py", line 454, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "/usr/lib/python2.7/dist-packages/mercurial/dispatch.py", line 733, in _runcommand
    return checkargs()
  File "/usr/lib/python2.7/dist-packages/mercurial/dispatch.py", line 687, in checkargs
    return cmdfunc()
  File "/usr/lib/python2.7/dist-packages/mercurial/dispatch.py", line 676, in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **cmdoptions)
  File "/usr/lib/python2.7/dist-packages/mercurial/util.py", line 385, in check
    return func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/mercurial/commands.py", line 5131, in update
    ret = hg.update(repo, rev)
  File "/usr/lib/python2.7/dist-packages/mercurial/hg.py", line 395, in update
    stats = mergemod.update(repo, node, False, False, None)
  File "/usr/lib/python2.7/dist-packages/mercurial/merge.py", line 554, in update
    stats = applyupdates(repo, action, wc, p2, pa, overwrite)
  File "/usr/lib/python2.7/dist-packages/mercurial/merge.py", line 329, in applyupdates
    subrepo.submerge(repo, wctx, mctx, wctx.ancestor(mctx), overwrite)
  File "/usr/lib/python2.7/dist-packages/mercurial/subrepo.py", line 156, in submerge
    mctx.sub(s).get(r)
  File "/usr/lib/python2.7/dist-packages/mercurial/subrepo.py", line 668, in get
    if self._svnversion >= (1, 5):
  File "/usr/lib/python2.7/dist-packages/mercurial/util.py", line 169, in __get__
    result = self.func(obj)
  File "/usr/lib/python2.7/dist-packages/mercurial/subrepo.py", line 567, in _svnversion
    output, err = self._svncommand(['--version'], filename=None)
  File "/usr/lib/python2.7/dist-packages/mercurial/subrepo.py", line 555, in _svncommand
    universal_newlines=True, env=env, **extrakw)
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1239, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory
abort: No such file or directory

我尝试过做rm -rf myrepo然后做hg clone ssh://[email protected]/myrepo但是该命令正确下载了存储库，但是当 hg 尝试将存储库更新为分支默认值时，我得到了相同的错误，更具体地说，我得到了这个：

destination directory: foo
requesting all changes
adding changesets
adding manifests
adding file changes
added 6270 changesets with 20990 changes to 3682 files
updating to branch default
abort: No such file or directory

使用引用引用时，我收到与之前类似的错误。我什至尝试在我的系统上重新安装 Mercurial，但没有任何运气。

您能指出是什么问题吗？回购头似乎没问题，（我可以clone and update在其他机器上），我能够clone or update我系统上的其他 hg 存储库。这与子存储库有什么关系吗？引文暗示了这一点。

我的系统详细信息：32位Ubuntu 11.10，运行mercurial版本1.9.1。

似乎源存储库有一个 svn 子存储库，并且您没有安装 subversion 客户端（或者 svn 不在搜索路径中）。