rspec/rules/S5654/python/rule.adoc
2021-04-28 18:08:03 +02:00

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As soon as the ``++yield++`` keyword is used the enclosing method or function becomes a generator. Thus ``++yield++`` should never be used in a function or method which is not intended to be a generator.
This rule raises an issue when ``++yield++`` or ``++yield from++`` are used in a function or method which is not a generator because:
* the function/method's return type annotation is not [``++typing.Generator[...]++``|https://docs.python.org/3/library/typing.html#typing.Generator]
* it is a special method which can never be a generator (ex: ``++__init__++``).
== Noncompliant Code Example
----
class A:
def __init__(self, value):
self.value = value
yield value # Noncompliant
def mylist2() -> List[str]:
yield ['string'] # Noncompliant. Return should be used instead of yield
def generator_ok() -> Generator[int, float, str]:
sent = yield 42
return '42'
----
== Compliant Solution
----
class A:
def __init__(self, value):
self.value = value
def mylist2() -> List[str]:
return ['string']
def generator_ok() -> Generator[int, float, str]:
sent = yield 42
return '42'
----
== See
* https://docs.python.org/3/library/typing.html[Python documentation - Support for type hints]
* https://docs.python.org/3/reference/datamodel.html#special-method-names[Python documentation - Special method names]