hgview crashes with error AttributeError: 'phasecache' object has no attribute '_phaserevs'

We open hgview and later we browse and select our mercurial repository. Later below error is thrown

Traceback (most recent call last):
  File "/usr/bin/hgview", line 38, in <module>
    main()
  File "/usr/lib/python2.7/dist-packages/hgviewlib/application.py", line 226, in main
    sys.exit(start(repo, opts, args, parser.error))
  File "/usr/lib/python2.7/dist-packages/hgviewlib/application.py", line 174, in start
    app = Application(repo, opts, args)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/qt4/application.py", line 54, in __init__
    super(HgViewQtApplication, self).__init__(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/application.py", line 84, in __init__
    self.choose_viewer()
  File "/usr/lib/python2.7/dist-packages/hgviewlib/application.py", line 108, in choose_viewer
    viewer = self.HgRepoViewer(self.repo)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/qt4/hgrepoviewer.py", line 87 , in __init__
    self.setupModels(fromhead)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/qt4/hgrepoviewer.py", line 48 0, in setupModels
    self.create_models(fromhead)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/qt4/hgrepoviewer.py", line 47 1, in create_models
    self.repomodel = HgRepoListModel(self.repo, fromhead=fromhead)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/qt4/hgrepomodel.py", line 137 , in __init__
    HgRepoListWalker.__init__(self, repo, branch, fromhead, follow, closed=close d)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/hggraph.py", line 677, in __i nit__
    self.setRepo(repo, branch=branch, fromhead=fromhead, follow=follow, closed=c losed)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/qt4/hgrepomodel.py", line 141 , in setRepo
    HgRepoListWalker.setRepo(self, repo, branch, fromhead, follow, closed=closed )
  File "/usr/lib/python2.7/dist-packages/hgviewlib/hggraph.py", line 715, in set Repo
    self.ensureBuilt(row=self.fill_step)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/hggraph.py", line 735, in ens ureBuilt
    self.graph.build_nodes(nnodes=required, rev=buildrev)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/hggraph.py", line 464, in bui ld_nodes
    for vnext in self.grapher:
  File "/usr/lib/python2.7/dist-packages/hgviewlib/hggraph.py", line 275, in rev ision_grapher
    phaserevs = _get_phaserevs(repo)
  File "/usr/lib/python2.7/dist-packages/hgviewlib/hggraph.py", line 161, in _ge t_phaserevs
    phaserevs = repo._phasecache._phaserevs
AttributeError: 'phasecache' object has no attribute '_phaserevs'