Honestly, I think this is one of the rougher parts of the language to see problems in. In my opinion, anything that can be done to either warn of retain cycles or enforce a better practice in this would be valuable. Josh
On Mar 3, 2017, at 1:14 PM, Alex Johnson via swift-evolution <swift-evolution@swift.org<mailto:swift-evolution@swift.org>> wrote: Hi list members, During code review today, I noticed a really subtle memory leak that looked like: self.relatedObject = RelatedObject(callback: relatedObjectDidFinish) Where `relatedObject` is a strong reference, `callback` is an escaping closure, and `relatedObjectDidFinish` is a method of `self`. From a memory management perspective, this code is equivalent to: self.relatedObject = RelatedObject(callback: { self.relatedObjectDidFinish }) In the second example, an explicit `self.` is required. It’s my understanding that this is to highlight that the closure keeps a strong reference to `self`. But, when passing a method, there is no such requirement, which makes it easier to accidentally create a retain cycle. This made me wonder if an explicit `self.` should be required when passing a method as an escaping closure. And whether that would help in the same way that the explicit `self.` *inside* the closure is intended to. If it were required, the code in the first example would be: self.relatedObject = RelatedObject(callback: self.relatedObjectDidFinish) What do you think? Alex Johnson ajohn...@walmartlabs.com<mailto:ajohn...@walmartlabs.com> ajohnson on Slack _______________________________________________ swift-evolution mailing list swift-evolution@swift.org<mailto:swift-evolution@swift.org> https://lists.swift.org/mailman/listinfo/swift-evolution Joshua Parmenter | Engineering Lead, Apple Technologies T 248 777 7777 C 206 437 1551 F 248 616 1980 www.vectorform.com<http://www.vectorform.com/> Vectorform 2107 Elliott Ave Suite 303 Seattle, WA 98121 USA Think Tank. Lab. Studio. We invent digital products and experiences. SEATTLE | DETROIT | NEW YORK | MUNICH | HYDERABAD _______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution
