[IPython-user] Problem with IPShellEmbed

Fernando Perez Fernando.Perez at colorado.edu
Fri Jan 28 04:24:44 CST 2005

Michael Foord wrote:
> I've encountered a problem with IPShellEmbed, for my Movable Python 
> project. It's quite likely that this problem is my fault - but I would 
> still appreciate help ! It looks like a frame object is expected and 
> None is returned.
> Basically *sometimes* a call to IPShellEmbed will fail :
> ipshell = IPShellEmbed(argv, banner=banner)
> The error raised occurs in :
>   File "C:\Python24\Lib\site-packages\IPython\Itpl.py", line 182, in __str__
>     while frame.f_globals["__name__"] == __name__: frame = frame.f_back
> AttributeError: 'NoneType' object has no attribute 'f_globals'

Very, very strange.  It seems like you have a stack with a bogus frame 
somewhere.  Here's something to try: in the Itpl.py file, around line 182, 
comment out 3 lines and add a _getframe as follows:

     def __str__(self):
         """Evaluate and substitute the appropriate parts of the string."""

##        try: 1/0
##        except: frame = sys.exc_traceback.tb_frame

##        while frame.f_globals["__name__"] == __name__: frame = frame.f_back

         frame = sys._getframe(1)   ##### <<<--- NEW LINE HERE

         loc, glob = frame.f_locals, frame.f_globals

This should pull the caller's frame correctly.  Itpl was originally written 
before sys._getframe existed, so it used the 1/0 trick.  If this fixes your 
problem, I'll add it for the next release.

Let me know what happens.



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