[Python-Dev] Two possible fixes for isinstance nested tuples (original) (raw)

Guido van Rossum guido at python.org
Sat Mar 20 16🔞15 EST 2004

Bug #858016 brought up the issue of deeply nested tuples of classes segfaulting isinstance and issubclass. There is a patch with the bug report that adds a check to make sure the tuple is completely shallow.

For Python 2.3, though, that doesn't work since it breaks code. So I have coded up something that calls PyGetRecursionLimit and makes sure the depth never goes past that. The question is which solution to use for Python 2.4 . I did some benchmarking on as-is and with the recursion check and the performance difference is no worse than 2% (granted this was before I made the recursion functions static, but that should just help performance). Would people rather do the recursion check or force people to use a shallow tuple in 2.4?

I mentioned in person to Brett to use the same solution in 2.4 as in 2.3.

--Guido van Rossum (home page: http://www.python.org/~guido/)

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