> Both ways, with OverflowError and Py3k DeprecationWarning, are good to me. What would you say about this Benjamin?
I prefer an OverflowError. I don't like having to enable a flag to fix a bug :-(
According to the issue title, it's really a bug: "format method: c presentation type *broken* in 2.7".
Note: The unit test may check the error message, currently the error message is irrevelant (it mentions unicode whereas bytes (str type) are used).
>>> format(-1, "c")
OverflowError: %c arg not in range(0x110000) (wide Python build)