bug_report.py

def collector(until=float('inf')):
    def decorator(func):
        def wrapper(*args, **kwargs):
            print(until)
            print(kwargs.pop("until", None))
            #until = kwargs.pop("until", None) or until
            val = kwargs.pop("until", until)
            for i in range(10):
                if i >= val:
                    break
            return func(i)
        return wrapper
    return decorator


@collector(until=5)
def works(item):
    return item



def collector_(until=float('inf')):
    def decorator(func):
        def wrapper(*args, **kwargs):
            print(until)
            print(kwargs.pop("until", None))
            # Added the below line, notice until on the end.
            # for some reason that completly removes until from the function scope
            # print(until)
            # UnboundLocalError: cannot access local variable 'until' where it is not associated with a value
            until = kwargs.pop("until", None) or until

            for i in range(10):
                if i >= until:
                    break
            return func(i)
        return wrapper
    return decorator


@collector_(until=5)
def does_not(item):
    return item

if __name__ == "__main__":
    print("start")
    print(works())
    print(works(until=3))
    print("above works")
    print("sma")
    print(does_not())

    print("stop")

output.txt

start
5
None
5
5
3
5
above works
sma
Traceback (most recent call last):
  File "/Users/mbijman/Development/meesee/bug_report.py", line 52, in <module>
    print(does_not())
          ^^^^^^^^^^
  File "/Users/mbijman/Development/meesee/bug_report.py", line 26, in wrapper
    print(until)
          ^^^^^
UnboundLocalError: cannot access local variable 'until' where it is not associated with a value