HG Pull fails for no apparent reason

I've not made any changes on my server and did an hg pull yesterday without any issues. Now, I get this:

pulling from ssh://hg@bitbucket.org/me/site/
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 4 changes to 2 files
transaction abort!
rollback completed
** unknown exception encountered, please report by visiting
** http://mercurial.selenic.com/wiki/BugTracker
** Python 2.7.5 (default, Jul 13 2018, 13:06:57) [GCC 4.8.5 20150623 (Red Hat 4.8.5-28)]
** Mercurial Distributed SCM (version 3.0.1)
** Extensions loaded:
Traceback (most recent call last):
  File "/home/leedhinde/bin/hg", line 5, in <module>
    pkg_resources.run_script('mercurial==3.0.1', 'hg')
  File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 488, in run_script
    self.require(requires)[0].run_script(script_name, ns)
  File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 1338, in run_script
    execfile(script_filename, namespace, namespace)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/EGG-INFO/scripts/hg", line 38, in <module>
    mercurial.dispatch.run()
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/dispatch.py", line 28, in run
    sys.exit((dispatch(request(sys.argv[1:])) or 0) & 255)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/dispatch.py", line 69, in dispatch
    ret = _runcatch(req)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/dispatch.py", line 138, in _runcatch
    return _dispatch(req)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/dispatch.py", line 819, in _dispatch
    cmdpats, cmdoptions)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/dispatch.py", line 599, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/dispatch.py", line 910, in _runcommand
    return checkargs()
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/dispatch.py", line 881, in checkargs
    return cmdfunc()
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/dispatch.py", line 816, in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **cmdoptions)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/util.py", line 518, in check
    return func(*args, **kwargs)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/commands.py", line 4607, in pull
    modheads = repo.pull(other, heads=revs, force=opts.get('force'))
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/localrepo.py", line 1708, in pull
    return exchange.pull (self, remote, heads, force)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/exchange.py", line 544, in pull
    _pullchangeset(pullop)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/exchange.py", line 632, in _pullchangeset
    pullop.remote.url())
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/changegroup.py", line 699, in addchangegroup
    phases.retractboundary(repo, phases.draft, added)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/phases.py", line 300, in retractboundary
    phcache = repo._phasecache.copy()
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/localrepo.py", line 29, in __get__
    return super(repofilecache, self).__get__(repo.unfiltered(), type)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/scmutil.py", line 892, in __get__
    entry.obj = self.func(obj)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/localrepo.py", line 401, in _phasecache
    return phases.phasecache(self, self._phasedefaults)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/phases.py", line 147, in __init__
    self.phaseroots, self.dirty = _readroots(repo, phasedefaults)
  File "/home/leedhinde/lib/python2.7/mercurial-3.0.1-py2.7-linux-x86_64.egg/mercurial/phases.py", line 130, in _readroots
    phase, nh = line.split()
ValueError: too many values to unpack

Lots of moving parts, but I thought I'd start here.