Error when setting color scheme in the IPython console

[thzpcs]

Problem Description

What steps will reproduce the problem?

Changing the default Emacs color scheme in Spyder caused it to crash

Traceback

  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\spyder\plugins\configdialog.py", line 214, in accept
    configpage.apply_changes()
  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\spyder\plugins\configdialog.py", line 104, in apply_changes
    self.apply_callback()
  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\spyder\plugins\configdialog.py", line 269, in <lambda>
    self.apply_settings(self.changed_options))
  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\spyder\plugins\configdialog.py", line 1183, in apply_settings
    self.main.ipyconsole.apply_plugin_settings(['color_scheme_name'])
  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\spyder\plugins\ipythonconsole.py", line 710, in apply_plugin_settings
    client.set_color_scheme(color_scheme_o)
  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\spyder\widgets\ipythonconsole\client.py", line 439, in set_color_scheme
    self.shellwidget.set_color_scheme(color_scheme, reset)
  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\spyder\widgets\ipythonconsole\shell.py", line 144, in set_color_scheme
    self.reset(clear=True)
  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\qtconsole\frontend_widget.py", line 665, in reset
    self._show_interpreter_prompt()
  File "C:\Users\Skyler\Anaconda2\envs\py36\lib\site-packages\qtconsole\jupyter_widget.py", line 348, in _show_interpreter_prompt
    msg_id = self.kernel_client.execute('', silent=True)
AttributeError: 'NoneType' object has no attribute 'execute'

Package Versions

• Spyder version: 3.2.8
• Python version: 3.6.4
• Qt version: 5.6.2
• PyQt5 version: 5.6
• Operating system: Windows 10

Dependencies

pyflakes >=0.6.0 :  1.6.0 (OK)
pycodestyle >=2.3:  2.3.1 (OK)
pygments >=2.0   :  2.2.0 (OK)
pandas >=0.13.1  :  0.22.0 (OK)
numpy >=1.7      :  1.14.0 (OK)
sphinx >=0.6.6   :  1.6.6 (OK)
rope >=0.9.4     :  0.10.7 (OK)
jedi >=0.9.0     :  0.11.1 (OK)
nbconvert >=4.0  :  5.3.1 (OK)
sympy >=0.7.3    :  1.1.1 (OK)
cython >=0.21    :  0.27.3 (OK)
qtconsole >=4.2.0:  4.3.1 (OK)
IPython >=4.0    :  6.2.1 (OK)
pylint >=0.25    :  1.8.2 (OK)

[ccordoba12]

Thanks for reporting. We'll fix this in our next release.

[ccordoba12]

@dalthviz, please work on this one by catching AttributeError around self.shellwidget.set_color_scheme(color_scheme, reset) in the method set_color_scheme of ClientWidget (in client.py)