[5.1 04-24-2019][Foundation] Modernize hashing in Foundation's Swift-only types #24369
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…*all* components The new definition diverges from the existing hashValue: it feeds all path components to the hasher, rather than just a limited subset. Hashing all the bits that are compared in == is necessary to ensure proper operation of the hash table.
This replaces the compiler-generated variant (based on hashValue) with a better implementation.
Note: URL does not implement Hashable.
I’m not sure why I was so convinced it wasn’t, but this certainly simplifies things.
…trary subset" This reverts commit b711ed9.
…bilize hashing The `ObjectIdentifier(object as AnyObject)` is not necessarily stable; this breaks reflexivity for ==, and it makes the hash encoding nondeterministic.
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airspeedswift
approved these changes
Apr 30, 2019
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This is cherry-picked from #23832 -- see there for an extended discussion.
This PR upgrades the Foundation overlay to use the new hashing API introduced in SE-0206. This gets rid of the deprecation warnings for
hashValueimplementations and brings the overlay in sync with current Swift best practices.Reviewed by: @itaiferber and @parkera
rdar://problem/43394032