pyglet "Unable to share contexts" exception when running PsychoPy demo twice - pyglet

Question

PsychoPy looks like just what I need. But I want to use my own development environment (a straightforward IPython prompt combined with the editor of my choice) instead of the provided IDE.
The trouble is that you seem to have to quit Python and relaunch after every PsychoPy run. If for example I cd to the ...../demos/coder/stimuli directory and type run gabor.py it runs fine, but if I then type run gabor.py again I get this exception from pyglet:
C:\snap\PsychoPy2\lib\site-packages\pyglet\window\win32\__init__.pyc in _create(self)
259 if not self._wgl_context:
260 self.canvas = Win32Canvas(self.display, self._view_hwnd, self._dc)
--> 261 self.context.attach(self.canvas)
262 self._wgl_context = self.context._context
263
C:\snap\PsychoPy2\lib\site-packages\pyglet\gl\win32.pyc in attach(self, canvas)
261 self._context = wglext_arb.wglCreateContextAttribsARB(canvas.hdc,
262 share, attribs)
--> 263 super(Win32ARBContext, self).attach(canvas)
C:\snap\PsychoPy2\lib\site-packages\pyglet\gl\win32.pyc in attach(self, canvas)
206 raise RuntimeError('Share context has no canvas.')
207 if not wgl.wglShareLists(share._context, self._context):
--> 208 raise gl.ContextException('Unable to share contexts')
209
210 def set_current(self):
ContextException: Unable to share contexts
Is there some sort of pyglet.cleanup() I can call (analogous to pygame.quit()) to allow PsychoPy scripts to run more than once in the same session? Or other way of avoiding this problem?
I'm using the Standalone PsychoPy distro version 1.81.02, untouched. The problem is not specific to IPython---it also can also be demonstrated from the plain Python prompt if you disable sys.exit and type execfile('gabor.py') twice:
C:\snap\PsychoPy2\Lib\site-packages\PsychoPy-1.81.02-py2.7.egg\psychopy\demos\coder\stimuli>python
Python 2.7.3 (default, Apr 10 2012, 23:31:26) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> import sys; sys.exit = lambda x:x
>>> execfile('gabor.py')
0.6560 WARNING Movie2 stim could not be imported and won't be available
1.6719 WARNING Monitor specification not found. Creating a temporary one...
>>>
>>> execfile('gabor.py')
Traceback (most recent call last):
[snip]
File "C:\snap\PsychoPy2\lib\site-packages\pyglet\gl\win32.py", line 208, in attach
raise gl.ContextException('Unable to share contexts')
pyglet.gl.ContextException: Unable to share contexts

Answer 1

I don't know how to undo all the pyglet/psychopy initialisation - neither are really designed for you to do this, so there would be some work here. But I'm not sure it's a good idea anyway to run scripts the way you are doing.
The PsychoPy app itself gets around the by launching each script in a new process. It means that you know the namespace is clean on each run. Running your script on top of the previous one can lead to some really hard-to-find bugs because you don't know in what state the previous script left the memory, graphics card and namespace.
cheers
Jon