Fails to run with qtconsole #13
Description
Executing jupyter qtconsole --kernel powershell results in a dialog box titled Error starting QtConsole with message box with the following error message:
Traceback (most recent call last):
File "E:\alex.hanson\anaconda3\envs\udt_py36_dev\lib\site-packages\qtconsole\base_frontend_mixin.py", line 138, in _dispatch
handler(msg)
File "E:\alex.hanson\anaconda3\envs\udt_py36_dev\lib\site-packages\qtconsole\jupyter_widget.py", line 307, in _handle_kernel_info_reply
self.kernel_banner = content.get('banner', 'test')
File "E:\alex.hanson\anaconda3\envs\udt_py36_dev\lib\site-packages\traitlets\traitlets.py", line 585, in __set__
self.set(obj, value)
File "E:\alex.hanson\anaconda3\envs\udt_py36_dev\lib\site-packages\traitlets\traitlets.py", line 559, in set
new_value = self._validate(obj, value)
File "E:\alex.hanson\anaconda3\envs\udt_py36_dev\lib\site-packages\traitlets\traitlets.py", line 591, in _validate
value = self.validate(obj, value)
File "E:\alex.hanson\anaconda3\envs\udt_py36_dev\lib\site-packages\traitlets\traitlets.py", line 2054, in validate
self.error(obj, value)
File "E:\alex.hanson\anaconda3\envs\udt_py36_dev\lib\site-packages\traitlets\traitlets.py", line 625, in error
raise TraitError(e)
traitlets.traitlets.TraitError: The 'kernel_banner' trait of a RichJupyterWidget instance must be a unicode string, but a value of None <class 'NoneType'> was specified.
Adding cmd line option --FrontendWidget.banner=test seems to have no effect. Although with other kernels it works just fine.
When debugging qtconsole.base_frontend_mixin.BaseFrontendMixin._dispatch, when it gets to powershell, banner is set to NoneType
And indeed PowerShellKernel._banner is set to None, where as IPythonKernel.banner returns self.shell.banner.
Setting PowerShellKernel._banner= '' is a workaround. However, the differences with other kernels leads me to believe there is something more at play here.