>From what I can tell the hash values of elements in a Set don't come into play during encoding/decoding: they're merely serialized as the sequence of their elements. https://github.com/apple/swift/blob/2e5817ebe15b8c2fc2459e08c1d462053cbb9a99/stdlib/public/core/Codable.swift#L4073-L4097
On Wed, Aug 16, 2017 at 4:06 PM Robert Bennett via swift-evolution < [email protected]> wrote: > How do unstable hash values play with Codable? If you encode and save a > Set, might you have problems interacting with it in the future? (This is > more a Codable question than Hashable, but I figure I might as well ask > here) > > On Aug 16, 2017, at 7:02 PM, Matthew Johnson via swift-evolution < > [email protected]> wrote: > > > On Aug 16, 2017, at 5:59 PM, Rudolf Adamkovic via swift-evolution < > [email protected]> wrote: > > That's great. Thanks! > > > Yes, excellent news! I am *really* looking forward to seeing this > proposal make it into an Xcode release! > > > R+ > > On 17 Aug 2017, at 00:46, John McCall <[email protected]> wrote: > > On Aug 16, 2017, at 6:35 PM, Rudolf Adamkovič via swift-evolution < > [email protected]> wrote: > > This is fantastic news! Any chance of this landing in Swift 4.x instead of > 5? > > > It it likely to be available in 4.1, but not 4.0. > > John. > > > R+ > > On 17 Aug 2017, at 00:29, Chris Lattner via swift-evolution < > [email protected]> wrote: > > Proposal Link: > https://github.com/apple/swift-evolution/blob/master/proposals/0185-synthesize-equatable-hashable.md > > The review of SE-0185 “Synthesizing Equatable and Hashable conformance” > ran from August 9…15, 2017. Feedback for the feature was glowingly > positive, and the proposal is accepted. The core team discussed the > concerns raised in the feedback thread for the proposal. Here are some > rough notes (not intended to be exhaustive), but it is important to > recognize that the proposal follows the design of the auto-synthesized > Codable proposal, and that many of these same points were discussed when it > came up: > > - The core team feels that adding compiler magic for this case is > reasonable because it solves an important user need, and doesn’t preclude > the introduction of a more general feature (e.g. like a macro system, or > Rust's ‘deriving’ feature) in the future. When/if that feature is designed > and built, the compiler magic can be replaced with standard library magic. > > - The hash value of a type is not intended to be stable across rebuilds or > other changes to the code. It is ok to change if fields are reordered, the > standard library changes the hash function, etc. Tony pointed this out > on-thread, saying: The stdlib documentation for hashValue states "Hash > values are not guaranteed to be equal across different executions of your > program. Do not save hash values to use during a future execution.” > > - The code synthesized is meant to feel like a default implementation that > you’re getting for free from a (constrained) extension on the protocol. > This is why conformance to the protocol itself is all that is required, not > something like “AutoEquatable”. > > Many thanks to Tony Allevato for driving forward this proposal. The patch > just needs final code review now - I think we’re all looking forward to > this landing, congrats! > > Chris Lattner > Review Manager > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution > > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution > > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution > > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution >
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