# init(upstream:receiveSubscription:receiveOutput:receiveCompletion:) Creates a breakpoint publisher with the provided upstream publisher and breakpoint-raising closures. ``` init(upstream: Upstream, receiveSubscription: ((any Subscription) -> Bool)? = nil, receiveOutput: ((Upstream.Output) -> Bool)? = nil, receiveCompletion: ((Subscribers.Completion.Failure>) -> Bool)? = nil) ``` ## Parameters `upstream` The publisher from which this publisher receives elements. `receiveSubscription` A closure that executes when the publisher receives a subscription, and can raise a debugger signal by returning a true Boolean value. `receiveOutput` A closure that executes when the publisher receives output from the upstream publisher, and can raise a debugger signal by returning a true Boolean value. `receiveCompletion` A closure that executes when the publisher receives completion, and can raise a debugger signal by returning a true Boolean value. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)