strange error whilst porting to 2.6

Robin Becker robin at
Sat Jan 24 03:00:23 CET 2009

Benjamin Peterson wrote:
> Robin Becker <robin <at>> writes:
>> python 2.6 indicates this error whilst running a script that works fine 
>> under Python 2.5.
>> Exception RuntimeError: 'maximum recursion depth exceeded in 
>> __subclasscheck__' in <type 'exceptions.AttributeError'> ignored
>> I suppose this must be related to some kind of isinstance or issubclass 
>> check, but how can I locate the problem if no traceback is shown?
> You're code is causing a RuntimeError to be raised some where in a type checking
> call. Unfortunately because of old APIs in CPython that are not "allowed" to
> fail, CPython cannot continue to raise the exception, so it just prints that
> ugly error message and clanks happily along. The best way to avoid this is just
> throw away sys.stderr in code that is acting up like this.
Well that's not really acceptable as a solution is it? :)
Robin Becker

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