This is more likely to be a bug in Pygame than in Python itself. What's likely happening here is that some part of the Pygame machinery is setting an exception state but then returning a value as normal. (Generally, if some function in a C extension sets an exception, that function should return NULL or -1.) That then leaves things in an inconsistent state, and Python doesn't notice that inconsistent state until the "int" call happens.

Please could you report to the Pygame folks, if you haven't done so already? It certainly is *possible* that it's actually a core Python bug, but even then the first step would be to eliminate the Pygame component from the code-to-reproduce.