jcheck still fails when run with Mercurial 4.8+:

** Unknown exception encountered with possibly-broken third-party extension defpath
** which supports versions unknown of Mercurial.
** Please disable defpath and try your action again.
** If that fixes the bug please report it to the extension author.
** Python 2.7.15+ (default, Nov 27 2018, 23:36:35) [GCC 7.3.0]
** Mercurial Distributed SCM (version 4.9.1)
** Extensions loaded: rebase, trees, defpath, jcheck, strip, mq
Traceback (most recent call last):
  File "mercurial-4.9.1/bin/hg", line 43, in <module>
    dispatch.run()
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 99, in run
    status = dispatch(req)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 225, in dispatch
    ret = _runcatch(req) or 0
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 376, in _runcatch
    return _callcatch(ui, _runcatchfunc)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 384, in _callcatch
    return scmutil.callcatch(ui, func)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/scmutil.py", line 165, in callcatch
    return func()
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 367, in _runcatchfunc
    return _dispatch(req)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 1021, in _dispatch
    cmdpats, cmdoptions)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 756, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 1030, in _runcommand
    return cmdfunc()
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/dispatch.py", line 1018, in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **strcmdopt)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/util.py", line 1670, in check
    return func(*args, **kwargs)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/util.py", line 1670, in check
    return func(*args, **kwargs)
  File "mercurial-4.9.1/lib/python2.7/site-packages/hgext/mq.py", line 3633, in mqcommand
    return orig(ui, repo, *args, **kwargs)
  File "mercurial-4.9.1/lib/python2.7/site-packages/mercurial/util.py", line 1670, in check
    return func(*args, **kwargs)
  File "jcheck.py", line 809, in jcheck
    changeiter, matchfn = cmdutil.walkchangerevs(ui, repo, [], get, opts)
TypeError: walkchangerevs() takes exactly 4 arguments (5 given)