$ cvs -z3 -d:pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/freedos co -P kernel > /dev/null
cvs checkout: Updating kernel
cvs checkout: Updating kernel/bin
cvs checkout: Updating kernel/boot
cvs checkout: Updating kernel/docs
cvs checkout: Updating kernel/drivers
cvs checkout: Updating kernel/hdr
cvs checkout: Updating kernel/kernel
cvs checkout: Updating kernel/kernel/nls
cvs checkout: Updating kernel/lib
cvs checkout: Updating kernel/mkfiles
cvs checkout: Updating kernel/share
cvs checkout: Updating kernel/sys
cvs checkout: Updating kernel/utils
$ hg convert kernel                                                                assuming destination kernel-hg
initializing destination kernel-hg repository
connecting to :pserver:anonymous@a.cvs.sourceforge.net:/cvsroot/freedos
** unknown exception encountered, please report by visiting
** https://mercurial-scm.org/wiki/BugTracker
** Python 3.9.2 (default, Feb 28 2021, 17:03:44) [GCC 10.2.1 20210110]
** Mercurial Distributed SCM (version 6.3.2)
** Extensions loaded: amend, children, churn, convert, fetch, graphlog, histedit, mq, patchbomb, purge, rebase, record, strip, transplant
Traceback (most recent call last):
  File "[home]/bin/hg", line 59, in <module>
    dispatch.run()
  File "[home]/lib/python/mercurial/dispatch.py", line 143, in run
    status = dispatch(req)
  File "[home]/lib/python/mercurial/dispatch.py", line 232, in dispatch
    status = _rundispatch(req)
  File "[home]/lib/python/mercurial/dispatch.py", line 276, in _rundispatch
    ret = _runcatch(req) or 0
  File "[home]/lib/python/mercurial/dispatch.py", line 451, in _runcatch
    return _callcatch(ui, _runcatchfunc)
  File "[home]/lib/python/mercurial/dispatch.py", line 461, in _callcatch
    return scmutil.callcatch(ui, func)
  File "[home]/lib/python/mercurial/scmutil.py", line 153, in callcatch
    return func()
  File "[home]/lib/python/mercurial/dispatch.py", line 441, in _runcatchfunc
    return _dispatch(req)
  File "[home]/lib/python/mercurial/dispatch.py", line 1265, in _dispatch
    return runcommand(
  File "[home]/lib/python/mercurial/dispatch.py", line 899, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "[home]/lib/python/mercurial/dispatch.py", line 1277, in _runcommand
    return cmdfunc()
  File "[home]/lib/python/mercurial/dispatch.py", line 1263, in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **strcmdopt)
  File "[home]/lib/python/mercurial/util.py", line 1880, in check
    return func(*args, **kwargs)
  File "[home]/lib/python/hgext/convert/__init__.py", line 510, in convert
    return convcmd.convert(ui, src, dest, revmapfile, **opts)
  File "[home]/lib/python/hgext/convert/convcmd.py", line 632, in convert
    srcc, defaultsort = convertsource(
  File "[home]/lib/python/hgext/convert/convcmd.py", line 156, in convertsource
    return source(ui, name, path, revs), sortmode
  File "[home]/lib/python/hgext/convert/cvs.py", line 60, in __init__
    self._connect()
  File "[home]/lib/python/hgext/convert/cvs.py", line 145, in _connect
    m = re.match(r'(?:(.*?)(?::(.*?))?@)?([^:/]*)(?::(\d*))?(.*)', root)
  File "/usr/lib/python3.9/re.py", line 191, in match
    return _compile(pattern, flags).match(string)
TypeError: cannot use a string pattern on a bytes-like object
$ hg --version
Mercurial Distributed SCM (version 6.3.2)
(see https://mercurial-scm.org for more information)

Copyright (C) 2005-2023 Olivia Mackall and others
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$