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Python dumps core with this.. how come?

Brad Howes bradh at mediaone.net
Fri Jan 21 23:26:01 EST 2000 
katz at glue.umd.edu (Roey Katz) writes:

<snip>

> When I import this module, the interpreter segfaults. 

<snip>

> class basic_monitor:
> 
>     def __init__( self ):
>         self.xres = []     # list of resource entries

This is innocuous line is the start of your troubles. Below you declare
__setattr__ which tells Python you want to handle all attributes settings for
this instance. So...

>     def __setattr__( self, name, val ):
>         origval = self.res[ name ]

But now you've asked for the attribute 'res' which has yet to be defined for
this instance. You've declared __getattr__ which tells Python to call it when
an attribute is not available (which it isn't yet)

>     def __getattr__( self, name ):
>         return self.res[ name ]

Here, we try to get the same attribute Python failed to get. So, Python calls
your hook again, and again, and again, until lack of stack tells Python to stop
this silliness and to go get a beer.

Since you've defined both hooks, you're going to have to work with the
instance's attribute dictionary __dict__

  dict = self.__dict__

and do your attribute setting using the usual dictionary methods (you could
also declare "class" attributes with default values) That should keep Python up
a bit longer.

Brad

-- 
Brad Howes                                              C C++ HTML Java Python
Waltham, MA                                                         Programmer

    "Were people this stupid before TV?" -- _White Noise_ by Don DeLillo
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