a = map(add, a, b) also crashes this.
a = chain(a, b) also.
If, by "provisions" you speak of sys.max_recursion_depth, that is only invoked when executing "python" code. What's happening here is just simple c recursion trough function pointers, ending in stack overflow, at least on Windows:
> python33_d.dll!chain_next(chainobject * lz) Line 1811 + 0x6 bytes C
python33_d.dll!PyIter_Next(_object * iter) Line 2741 + 0xf bytes C
python33_d.dll!chain_next(chainobject * lz) Line 1823 + 0xc bytes C
python33_d.dll!PyIter_Next(_object * iter) Line 2741 + 0xf bytes C
python33_d.dll!chain_next(chainobject * lz) Line 1823 + 0xc bytes C
python33_d.dll!PyIter_Next(_object * iter) Line 2741 + 0xf bytes C