SE-0268 adjusts the way the didSet property observers work so that they are more efficient. This doesn’t require a code change unless you were somehow relying on the previous buggy behavior; you’ll just get a small performance improvement for free.
Internally, this change makes Swift not retrieve the previous value when setting a new value in any instance where you weren’t using the old value, and if you don’t reference oldValue and don’t have a willSet Swift will change your data in-place.
If you do happen to be relying on the old behavior, you can work around it simply by referencing oldValue to trigger your custom getter, like this:
didSet {
_ = oldValue
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Other changes in Swift 5.3…
- Multi-pattern catch clauses
- Multiple trailing closures
- Synthesized Comparable conformance for enums
- self is no longer required in many places
- Type-based program entry points
- where clauses on contextually generic declarations
- Enum cases as protocol witnesses
- A new Float16 type
- Swift Package Manager gains binary dependencies, resources, and more
Download all Swift 5.3 changes as a playground Link to Swift 5.3 changes
