[Python-Dev] Two possible fixes for isinstance nested tuples

[Brett Cannon]

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 Py_GetRecursionLimit 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?

-Brett