Why does pycharm propose to change method to static
The new pycharm release (3.1.3 community edition) proposes to convert the methods that don't work with the current object's state to static.
What is the practical reason for that? Some kind of micro-performance(-or-memory)-optimization?
PyCharm "thinks" that you might have wanted to have a static method, but you forgot to declare it to be static.
PyCharm proposes this because the method does not use self in its body and hence does not actually change the class instance. Hence the method could be static, ie callable without having created a class instance before.
Agreed with @jolvi, @ArundasR, and others, the warning happens on a member function that doesn't use self .
If you're sure PyCharm is wrong, that the function should not be a @staticmethod , and if you value zero warnings, you can make this one go away two different ways:
Workaround #1
def bar(self):
self.is_not_used()
doing_something_without_self()
def is_not_used(self):
pass
Workaround #2 [Thanks @DavidPärsson]
# noinspection PyMethodMayBeStatic
def bar(self):
doing_something_without_self()
The application I had for this (the reason I could not use @staticmethod) was in making a table of handler functions for responding to a protocol subtype field. All handlers had to be the same form of course (static or nonstatic). But some didn't happen to do anything with the instance. If I made those static I'd get "TypeError: 'staticmethod' object is not callable".
In support of the OP's consternation, suggesting you add staticmethod whenever you can, goes against the principle that it's easier to make code less restrictive later, than to make it more -- making a method static makes it less restrictive now, in that you can call class.f() instead of instance.f().
Guesses as to why this warning exists:
I can imagine following advantages of having a class method defined as static one:
remaining advantages are probably marginal if present at all:
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