That's awesome. It looks like `(planned) Open and closed enums` is exactly what I'm looking for.
Would it help if I created a concrete proposal for that or is it something the Swift team already has brewing? Sent from my iPhone > On Feb 7, 2017, at 22:01, Michael Ilseman <[email protected]> wrote: > > BTW, this will likely be part of the eventual design of “open”/resilient > enums ala > https://github.com/apple/swift/blob/master/docs/LibraryEvolution.rst#enums. > There, the goal is to reduce both ABI and source breakage caused by this sort > of thing. It seems like for your purposes, you’re less inclined to care about > ABI breakage than source breakage, though that may change in the future. > > > >> On Feb 7, 2017, at 7:12 AM, Tanner Nelson via swift-evolution >> <[email protected]> wrote: >> >> Hello Swift Evolution, >> >> I'd like to propose that a warning be emitted when default cases are omitted >> for enums from other modules. >> >> What this would look like: >> >> OtherModule: >> ``` >> public enum SomeEnum { >> case one >> case two >> } >> >> public let global: SomeEnum = .one >> ``` >> >> executable: >> ``` >> import OtherModule >> >> switch OtherModule.global { >> case .one: break >> case .two: break >> ^~~~~ ⚠︎ Warning: Default case recommended for imported enums. Fix-it: >> Add `default: break` >> } >> ``` >> >> Why: >> >> Allowing the omission of a default case in an exhaustive switch makes the >> addition of a new case to the enum a breaking change. >> In other words, if you're exhaustively switching on an enum from an imported >> library, the imported library can break your code by adding a new case to >> that enum (which the library authors may erroneously view as an >> additive/minor-bump change). >> >> Background: >> >> As a maintainer of a Swift framework, public enums have been a pain point in >> maintaining semver. They've made it difficult to implement additive features >> and have necessitated the avoidance of enums in our future public API plans. >> >> Related Twitter thread: >> https://twitter.com/tanner0101/status/796860273760104454 >> >> Looking forward to hearing your thoughts. >> >> Best, >> Tanner >> >> Tanner Nelson >> Vapor >> +1 (435) 773-2831 >> >> >> >> >> >> >> >> _______________________________________________ >> swift-evolution mailing list >> [email protected] >> https://lists.swift.org/mailman/listinfo/swift-evolution >
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