This is a follow up to CODETOOLS-7902421 the proposed fix for which allows to work with Hg4 however after upgrade to Hg5 the following error shows up for example on an attempt to commit:

error: pretxncommit.jcheck hook raised an exception: object of type 'branchcache' has no len()


** Unknown exception encountered with possibly-broken third-party extension jcheck
** which supports versions unknown of Mercurial.
** Please disable jcheck and try your action again.
** If that fixes the bug please report it to the extension author.
** Python 2.7.16 (default, Mar 12 2019, 13:03:28) [GCC 4.2.1 Compatible Apple LLVM 10.0.0 (clang-1000.11.45.5)]
** Mercurial Distributed SCM (version 5.0)
** Extensions loaded: fetch, strip, mq, purge, extdiff, jcheck
Traceback (most recent call last):
  File "/usr/local/bin/hg", line 43, in <module>
    dispatch.run()
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/dispatch.py", line 99, in run
    status = dispatch(req)
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/dispatch.py", line 225, in dispatch
    ret = _runcatch(req) or 0
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/dispatch.py", line 376, in _runcatch
    return _callcatch(ui, _runcatchfunc)
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/dispatch.py", line 384, in _callcatch
    return scmutil.callcatch(ui, func)
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/scmutil.py", line 167, in callcatch
    return func()
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/dispatch.py", line 367, in _runcatchfunc
    return _dispatch(req)
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/dispatch.py", line 1021, in _dispatch
    cmdpats, cmdoptions)
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/dispatch.py", line 756, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "/usr/local/Cellar/mercurial/5.0/lib/python2.7/site-packages/mercurial/dispatch.py", line 1030, in _runcommand
    return cmdfunc()