Status: Accepted Owner: stephane...@gmail.com CC: siguc...@gmail.com, ryd...@gmail.com Labels: Milestone-1.3 New issue 3821 by stephane...@gmail.com: makeStrong/makeWeak contains a bug http://code.google.com/p/pharo/issues/detail?id=3821 makeStrong/makeWeak contains a bug, because it is using #becomeForward: but doesn't takes into account that subscription stored in a set , which is hash-based , so after become, the item will be at wrong position. So, we need to implement announcer>>replace: subscription with: newOne then a) we don't have to use become b) it will be thread safe, because you can protect replacement in subscription registry with monitor As an alternative, we can use Set instead of IdentitySet, and implement #hash and #== for subscriptions which don't changing when you switch between weak/strong. Then we can keep using #becomeForward: -- Best regards, Igor Stasenko AKA sig.