cubicweb-conference #5280818 crash in TrackTalksSchedule [open]

2015-04-20 09:52:16 - (cubicweb.web) ERROR: TypeError("unsupported operand type(s) for +: 'NoneType' and 'datetime.timedelta'",)
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/cubicweb/web/application.py", line 462, in core_handle
    result = controller.publish(rset=rset)
  File "/usr/lib/python2.7/dist-packages/cubicweb/web/views/basecontrollers.py", line 136, in publish
    rset=rset, view=view)
  File "/usr/lib/python2.7/dist-packages/cubicweb/cwvreg.py", line 388, in main_template
    res = obj.render(**kwargs)
  File "/usr/lib/python2.7/dist-packages/cubicweb/view.py", line 136, in render
    view_func(**context)
  File "/usr/lib/python2.7/dist-packages/cubicweb/web/views/basetemplates.py", line 163, in call
    view.render(w=w)
  File "/usr/lib/python2.7/dist-packages/cubicweb/view.py", line 136, in render
    view_func(**context)
  File "/usr/lib/python2.7/dist-packages/cubicweb/view.py", line 341, in call
    super(EntityView, self).call(**kwargs)
  File "/usr/lib/python2.7/dist-packages/cubicweb/view.py", line 186, in call
    self.cell_call(row=0, **kwargs)
  File "/usr/share/cubicweb/cubes/conference/views/track.py", line 56, in cell_call
    for day in date_range(track_cal.start, track_cal.stop+ONEDAY):
TypeError: unsupported operand type(s) for +: 'NoneType' and 'datetime.timedelta'
priorityimportant
typebug
done in0.15.0
closed by<not specified>