Earlier today I read about this strange case in
Fatal Python error: Cannot recover from stack overflow.
Current thread 0x000025ec (most recent call first):
File "`<stdin>`", line 3 in caseThree
It seems that the error you're encountering is actually expected, as it is explicitly tested for in
Now, without criticizing your colorful experiments, this is also the cause of a bug that causes a segfault (sometimes, see issue); there has already been one report of this to the Python bug tracker as issue 28179.
Keep an eye on that thread if you're curious as to what is causing this.