This is not a bug in Python, it is an invalid (broken) regular expression. There is nothing that the interpreter or the regular expression engine can do, because you are telling it to do something that makes no sense. What do you expect findall to find, if you ask it to find something nonsensical?

You say:

"repeat this pattern any number of times"

but there is no "this pattern" to be repeated. You are asking for something impossible. The only legitimate response is to report back that the regular expression is invalid and cannot be compiled, and fail immediately.