On 23 November 2015 at 02:32, Glyph Lefkowitz <glyph@twistedmatrix.com> wrote:

On Nov 22, 2015, at 07:04, Adi Roiban <adi@roiban.ro> wrote:

The @deprecated decorator (at leas on py2.7) does not work when paired @property

For deprecated instance variables, our deprecation policy recommend converting them into properties and emitted the warning from there. It would be nice if we could use the standard @deprecated decorator here.

The problem is that when property are used the fget/fset are received by the @deprecated wrapper as functions and not as methods

Is there a way to get the class in which a property is defined... or there is no way to use the @deprecated decorator with the @property .. and we should create a dedicated deprecatedMember method which is called as a normal method.

If you care about inheritance, the implementation is a little bit tricky, because you have to manually walk the class hierarchy looking for the attribute. But conceptually it's pretty simple: just look at the type of 'oself' in the __get__ method of the returned descriptor.

Right now, @deprecated is hard-coded to assume a function, but it could be repurposed to work with specific other descriptor types reasonably easily. *Arbitrary* descriptors might be hard, because it's not clear when to emit the message, but specific types like @property should be pretty straightforward with an instance check.

I think that we can go with a dedicated instance check for properties...

this is about the @deprecated decorator and using it together with the deprecation policy for instance members. I have created a dedicated ticket https://twistedmatrix.com/trac/ticket/8124 I still don't know how to fix it... I tried following property.__get__ and property.getter and property.fget

From what I understand of how Python works, at the time when the decorator is called, the class is not yet created / does not yet exists.

This will not work class SomeClass(object): @deprecated( Version("Twisted", 16, 0, 0), 'the deferred returned by start()') @property def deferred(self): """ DEPRECATED. Deferred fired when loop stops or fails. """ return self._deferred And I should use something like this class SomeClass(object): @property def deferred(self): """ DEPRECATED. Deferred fired when loop stops or fails. """ deprecated( Version("Twisted", 16, 0, 0), 'the deferred returned by start()') return self._deferred --------- Will push the tests and will ask for help in the review queue. Thanks! -- Adi Roiban

On Nov 23, 2015, at 07:38, Adi Roiban <adi@roiban.ro> wrote:

Will push the tests and will ask for help in the review queue.

Thanks!

Another option is to fix @deprecated to call getDeprecationWarningString when the method is called not when it is created.

I think you mean the other way around? property() objects are not necessarily called. -g