jupyter-cadquery: MyBinder Broken

I’m on Firefox 81 on Ubuntu 18.04 64-bit.

Is the binder still up to date and maintained? I was trying to help a CadQuery user on Discord get started with jupyter-cadquery, but we can’t get the binder to work. The user wants the widgets to dynamically adjust parameters.

https://mybinder.org/v2/gh/bernhard-42/jupyter-cadquery/v1.0.0?urlpath=lab&filepath=examples%2Fcadquery.ipynb

If I navigate to the examples directory and open cadquery-examples.ipynb, then execute the first two code cells, everything seems fine. But then if I try to execute cells further down, the 3D view doesn’t update. Trying different combinations of things causes other problems. If I call disable_replay() in the first cell then I start getting errors like this:

---------------------------------------------------------------------------
TraitError                                Traceback (most recent call last)
<ipython-input-9-2df1979a6696> in <module>
     10 result = cq.Workplane("XY").box(length, height, thickness)
     11 
---> 12 replay(result)

/srv/conda/envs/notebook/lib/python3.7/site-packages/jupyter_cadquery/cadquery/replay.py in replay(cad_obj, index, debug, cad_width, height)
    391         description='',
    392         disabled=False,
--> 393         layout=Layout(width="600px"))
    394     r.select_box.add_class("monospace")
    395     r.select_box.observe(r.select_handler)

/srv/conda/envs/notebook/lib/python3.7/site-packages/ipywidgets/widgets/widget_selection.py in __init__(self, *args, **kwargs)
    324         self._options_values = tuple(i[1] for i in options)
    325 
--> 326         super(_MultipleSelection, self).__init__(*args, **kwargs)
    327         self._initializing_traits_ = False
    328 

/srv/conda/envs/notebook/lib/python3.7/site-packages/ipywidgets/widgets/widget.py in __init__(self, **kwargs)
    410         """Public constructor"""
    411         self._model_id = kwargs.pop('model_id', None)
--> 412         super(Widget, self).__init__(**kwargs)
    413 
    414         Widget._call_widget_constructed(self)

/srv/conda/envs/notebook/lib/python3.7/site-packages/traitlets/traitlets.py in __init__(self, *args, **kwargs)
    998                 else:
    999                     # passthrough args that don't set traits to super
-> 1000                     super_kwargs[key] = value
   1001         try:
   1002             super(HasTraits, self).__init__(*super_args, **super_kwargs)

/srv/conda/envs/notebook/lib/python3.7/contextlib.py in __exit__(self, type, value, traceback)
    117         if type is None:
    118             try:
--> 119                 next(self.gen)
    120             except StopIteration:
    121                 return False

/srv/conda/envs/notebook/lib/python3.7/site-packages/traitlets/traitlets.py in hold_trait_notifications(self)
   1120                                 self._trait_values.pop(name)
   1121                 cache = {}
-> 1122                 raise e
   1123             finally:
   1124                 self._cross_validation_lock = False

/srv/conda/envs/notebook/lib/python3.7/site-packages/traitlets/traitlets.py in hold_trait_notifications(self)
   1106                 for name in list(cache.keys()):
   1107                     trait = getattr(self.__class__, name)
-> 1108                     value = trait._cross_validate(self, getattr(self, name))
   1109                     self.set_trait(name, value)
   1110             except TraitError as e:

/srv/conda/envs/notebook/lib/python3.7/site-packages/traitlets/traitlets.py in _cross_validate(self, obj, value)
    597         if self.name in obj._trait_validators:
    598             proposal = Bunch({'trait': self, 'value': value, 'owner': obj})
--> 599             value = obj._trait_validators[self.name](obj, proposal)
    600         elif hasattr(obj, '_%s_validate' % self.name):
    601             meth_name = '_%s_validate' % self.name

/srv/conda/envs/notebook/lib/python3.7/site-packages/traitlets/traitlets.py in __call__(self, *args, **kwargs)
    905         """Pass `*args` and `**kwargs` to the handler's function if it exists."""
    906         if hasattr(self, 'func'):
--> 907             return self.func(*args, **kwargs)
    908         else:
    909             return self._init_call(*args, **kwargs)

/srv/conda/envs/notebook/lib/python3.7/site-packages/ipywidgets/widgets/widget_selection.py in _validate_index(self, proposal)
    350             return proposal.value
    351         else:
--> 352             raise TraitError('Invalid selection: index out of bounds')
    353 
    354     @observe('index')

TraitError: Invalid selection: index out of bounds