No longer able to access the Hg repository.

[WenCong Ji]

Dear maintainer,
I can no longer get access to the Mercurial repository. It gives me
following error when I try to clone/pull:

$ hg pull -u
searching for changes
** unknown exception encountered, please report by visiting
** https://mercurial-scm.org/wiki/BugTracker
** Python 2.7.15+ (default, Oct  7 2019, 17:39:04) [GCC 7.4.0]
** Mercurial Distributed SCM (version 5.2.1)
** Extensions loaded:
Traceback (most recent call last):
  File "/usr/local/bin/hg", line 36, in <module>
    dispatch.run()
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
111, in run
    status = dispatch(req)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
250, in dispatch
    ret = _runcatch(req) or 0
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
424, in _runcatch
    return _callcatch(ui, _runcatchfunc)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
433, in _callcatch
    return scmutil.callcatch(ui, func)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/scmutil.py", line
177, in callcatch
    return func()
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
414, in _runcatchfunc
    return _dispatch(req)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
1174, in _dispatch
    lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
862, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
1185, in _runcommand
    return cmdfunc()
  File "/usr/local/lib/python2.7/dist-packages/mercurial/dispatch.py", line
1171, in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **strcmdopt)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/util.py", line
1843, in check
    return func(*args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/commands.py", line
5453, in pull
    opargs=pullopargs,
  File "/usr/local/lib/python2.7/dist-packages/mercurial/exchange.py", line
1780, in pull
    _fullpullbundle2(repo, pullop)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/exchange.py", line
1673, in _fullpullbundle2
    _pullbundle2(pullop)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/exchange.py", line
1976, in _pullbundle2
    bundle = e.callcommand(b'getbundle', args).result()
  File
"/usr/local/lib/python2.7/dist-packages/mercurial/thirdparty/concurrent/futures/_base.py",
line 457, in result
    return self.__get_result()
  File
"/usr/local/lib/python2.7/dist-packages/mercurial/wireprotov1peer.py", line
227, in sendcommands
    result = fn(**pycompat.strkwargs(args))
  File
"/usr/local/lib/python2.7/dist-packages/mercurial/wireprotov1peer.py", line
472, in getbundle
    return bundle2.getunbundler(self.ui, f)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/bundle2.py", line
769, in getunbundler
    magicstring = changegroup.readexactly(fp, 4)
  File "/usr/local/lib/python2.7/dist-packages/mercurial/util.py", line
3583, in readexactly
    s = stream.read(n)
  File
"/usr/local/lib/python2.7/dist-packages/mercurial/utils/compression.py",
line 378, in read
    self._decompress(chunk)
  File
"/usr/local/lib/python2.7/dist-packages/mercurial/utils/compression.py",
line 438, in _decompress
    newbuf = self._decompobj.decompress(chunk)
zstd.ZstdError: zstd decompressor error: Unknown frame descriptor

Please help to solve this problem.

------
Ji WenCong <taiki_akita at 163.com>
Harbin Institute of Technology.