rspec/rules/S2734/python/rule.adoc

This rule raises an issue when the ``++__init__++`` method of a class contains a `return` or a `yield` statement.

== Why is this an issue?

By contract, every Python function returns something, even if it is the ``++None++`` value, which can be returned implicitly by omitting the ``++return++`` statement, or explicitly. 


The ``++__init__++`` method is required to return ``++None++``. A ``++TypeError++`` will be raised if the ``++__init__++`` method either yields or returns any expression other than ``++None++``. While explicitly returning an expression that evaluates to ``++None++`` will not raise an error, it is considered bad practice.

To fix this issue, make sure that the ``++__init__++`` method does not contain any return statement.

=== Code examples

==== Noncompliant code example

[source,python,diff-id=1,diff-type=noncompliant]
----
class MyClass(object):
    def __init__(self):
        self.message = 'Hello'
        return self  # Noncompliant: a TypeError will be raised
----


==== Compliant solution

[source,python,diff-id=1,diff-type=compliant]
----
class MyClass(object):
    def __init__(self):
        self.message = 'Hello'
----

== Resources

=== Documentation

* https://docs.python.org/3/reference/datamodel.html#object.++__init__++[The ``++__init__++`` method]


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

* Remove this yield statement.
* Remove this return value.


'''
== Comments And Links
(visible only on this page)

=== relates to: S5654

=== on 18 Mar 2015, 17:55:42 Ann Campbell wrote:
-E0100: __init__ method is a generator

-E0101: Explicit return in __init__

endif::env-github,rspecator-view[]