New start task: https://bugs.swift.org/browse/SR-4405 <https://bugs.swift.org/browse/SR-4405> Add @escaping to RecoverableError.attemptRecovery
> On Mar 28, 2017, at 3:31 PM, Douglas Gregor <dgre...@apple.com> wrote: > > >> On Mar 28, 2017, at 11:21 AM, Michael Ilseman <milse...@apple.com >> <mailto:milse...@apple.com>> wrote: >> >> CC Doug Gregor, who git blame tells me wrote this part. >> >> Doug, this slightly predates noescape-by-default. Is this a bug or as >> intended? > > It’s a bug; the point here is that we can do recovery asynchronously, so it > should be @escaping. We missed the annotation when noescape-by-default landed. > > - Doug > >> >> >>> On Mar 28, 2017, at 8:49 AM, Elia Cereda via swift-users >>> <swift-users@swift.org <mailto:swift-users@swift.org>> wrote: >>> >>> Hi Dennis, >>> >>> Thanks for your answer. I can see that my message needs some more context: >>> RecoverableError is a protocol in the standard library that can be >>> implemented to opt in to the error recovery mechanism available on macOS. >>> attemptRecovery(optionIndex, resultHandler:) is one of the methods that >>> have to be implemented to conform to the protocol. >>> >>> Here you can find the other ones: >>> >>> /// Describes an error that may be recoverable by presenting several >>> /// potential recovery options to the user. >>> public protocol RecoverableError : Error { >>> >>> /// Provides a set of possible recovery options to present to the user. >>> public var recoveryOptions: [String] { get } >>> >>> /// Attempt to recover from this error when the user selected the >>> /// option at the given index. This routine must call handler and >>> /// indicate whether recovery was successful (or not). >>> /// >>> /// This entry point is used for recovery of errors handled at a >>> /// "document" granularity, that do not affect the entire >>> /// application. >>> public func attemptRecovery(optionIndex recoveryOptionIndex: Int, >>> resultHandler handler: (Bool) -> Swift.Void) >>> >>> /// Attempt to recover from this error when the user selected the >>> /// option at the given index. Returns true to indicate >>> /// successful recovery, and false otherwise. >>> /// >>> /// This entry point is used for recovery of errors handled at >>> /// the "application" granularity, where nothing else in the >>> /// application can proceed until the attempted error recovery >>> /// completes. >>> public func attemptRecovery(optionIndex recoveryOptionIndex: Int) -> >>> Bool >>> } >>> >>> As you can see, there are two attemptRecovery methods. In my mind the first >>> one was meant to be used for asynchronous operations, where you run some >>> recovering code in background and then report its result back to the caller. >>> >>> The problem is that the handler is not marked as @escaping and as such it >>> can only be used inside the body of attemptRecovery. I was wondering if >>> this was an oversight from the stdlib team or if this was a deliberate >>> design decision. >>> >>> I just saw that the method is still not marked as @escaping in master >>> (https://github.com/apple/swift/blob/master/stdlib/public/SDK/Foundation/NSError.swift#L105 >>> >>> <https://github.com/apple/swift/blob/master/stdlib/public/SDK/Foundation/NSError.swift#L105>), >>> so I’d like to know what its intended use case is, since the obvious one >>> (asynchronous recovery) is prevented by the missing annotation. >>> >>> Thanks, >>> Elia Cereda >>> >>>> Il giorno 28 mar 2017, alle ore 17:33, Dennis Weissmann >>>> <den...@dennisweissmann.me <mailto:den...@dennisweissmann.me>> ha scritto: >>>> >>>> Hey Elia, >>>> >>>> I'm currently on mobile and don't really know what you're talking about >>>> (what is RecoverableError?) but you say it's a block, and if the closure >>>> is optional, it is @escaping by default. >>>> >>>> Did you see >>>> https://lists.swift.org/pipermail/swift-users/Week-of-Mon-20160905/003185.html >>>> >>>> <https://lists.swift.org/pipermail/swift-users/Week-of-Mon-20160905/003185.html> >>>> >>>> - Dennis >>>> >>>> Sent from my iPhone >>>> >>>> On 23. Mar 2017, at 10:07 AM, Elia Cereda via swift-users >>>> <swift-users@swift.org <mailto:swift-users@swift.org>> wrote: >>>> >>>>> I'd like to bump this issue, since it has been some time and it hasn't >>>>> been addressed. >>>>> >>>>> Thanks, >>>>> Elia Cereda >>>>> >>>>> Il giorno 03 mar 2017, alle ore 21:33, Elia Cereda <eliacer...@gmail.com >>>>> <mailto:eliacer...@gmail.com>> ha scritto: >>>>> >>>>>> I’m wondering why the resultHandler block on >>>>>> RecoverableError.attemptRecovery(optionIndex, resultHandler:) is not >>>>>> marked @escaping? >>>>>> >>>>>> I’m trying to invoke some recovering code that executes asynchronously, >>>>>> then reports if it was successful or not and I thought that this was the >>>>>> right strategy. As far as I can tell, without @escaping that method >>>>>> loses all it’s purpose and becomes essentially equivalent to >>>>>> attemptRecovery(optionIndex:). >>>>>> >>>>>> So, I’d like to ask. >>>>>> 1. Is it a bug or that method is non-escaping on purpose? >>>>>> 2. If it is a bug, is there a workaround that can be applied pending a >>>>>> fix in a future version of Swift? >>>>>> 3. If it was a deliberate decision, what's the supported method of >>>>>> asynchronously invoking error recovery code? >>>>>> >>>>>> Seeing that this wasn’t changed in Xcode 8.3b2, I think it unlikely that >>>>>> this was an oversight. >>>>>> >>>>>> Thanks, >>>>>> Elia Cereda >>>>>> >>>>> _______________________________________________ >>>>> swift-users mailing list >>>>> swift-users@swift.org <mailto:swift-users@swift.org> >>>>> https://lists.swift.org/mailman/listinfo/swift-users >>>>> <https://lists.swift.org/mailman/listinfo/swift-users> >>> >>> _______________________________________________ >>> swift-users mailing list >>> swift-users@swift.org <mailto:swift-users@swift.org> >>> https://lists.swift.org/mailman/listinfo/swift-users >>> <https://lists.swift.org/mailman/listinfo/swift-users> >> >
_______________________________________________ swift-users mailing list swift-users@swift.org https://lists.swift.org/mailman/listinfo/swift-users
