return-arg-in-generator / E0106

Message emitted:

Return with argument inside generator

Description:

Used when a "return" statement with an argument is found in a generator function or method (e.g. with some "yield" statements).

Correct code:

def yield_numbers():
    for number in range(10):
        yield number
        return "I am now allowed!"  # This was not allowed in Python 3.3 and earlier.

Additional details:

This is a message that isn't going to be raised for python > 3.3. It was raised for code like:

def interrogate_until_you_find_jack(pirates):
    for pirate in pirates:
        if pirate == "Captain Jack Sparrow":
            return "Arrr! We've found our captain!"
        yield pirate

Which is now valid and equivalent to the previously expected:

def interrogate_until_you_find_jack(pirates):
    for pirate in pirates:
        if pirate == "Captain Jack Sparrow":
            raise StopIteration("Arrr! We've found our captain!")
        yield pirate

Related links:

• PEP380

• Stackoverflow explanation

Created by the basic checker.