One of the most fun discussions of the complications of reference counting and how nuanced you have to be comes from the Python docs: http://docs.python.org/ex

One of the most fun discussions of the complications of reference counting and how nuanced you have to be comes from the Python docs: http://docs.python.org/extending/extending.html#reference-counts http://docs.python.org/extending/extending.html#reference-co... It relates "a true story. An older version of Python contained variants of this bug and someone spent a considerable amount of time in a C debugger to figure out why his __del__() methods would fail" in a considerable amount of detail.