Marked objects as Sendable or explicitly not Sendable #8
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Package.swift
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| @@ -65,6 +65,7 @@ let defaultSwiftSettings: [SwiftSetting] = | |||
| .enableUpcomingFeature("ExistentialAny"), | |||
| .enableUpcomingFeature("InternalImportsByDefault"), | |||
| .enableUpcomingFeature("MemberImportVisibility"), | |||
| .unsafeFlags(["-Xfrontend", "-require-explicit-sendable"]), | |||
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We can't unconditionally add this flag here; these flags are always enabled. This one should only be added for development.
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Forgot to remove it! Thanks for the reminder.
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We can still have it so we can enable it during development though - here's an example: https://github.com/apple/swift-nio-ssl/blob/main/Package.swift#L59-L73
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Okay, let me add this then.
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I don't think we need to add it back behind a flag. It was helpful when we were doing lots of strict concurrency work, but we're very unlikely to flip that flag back on now that the work has been done.
| @@ -49,7 +49,7 @@ struct AsyncSequenceOfOne<Element: Sendable, Failure: Error>: AsyncSequence, Sen | |||
| } | |||
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| @usableFromInline | |||
| struct AsyncIterator: AsyncIteratorProtocol { | |||
| struct AsyncIterator: AsyncIteratorProtocol, Sendable { | |||
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In general, iterators aren't Sendable
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Should I mark it as not Sendable even though it currently conforms to Sendable then?
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The fact it implicitly conforms to Sendable right now because its implementation ticks all the boxes doesn't mean it should be Sendable when you consider the semantics. In general, all iterators keep some internal state to know what the next item should be. If an iterator is shared between different tasks, then it becomes undeterministic which task gets which element, which isn't good.
Also, I left the comment on this iterator but this should be true for all other iterators marked as Sendable on this PR.
Performed the necessary changes to enable compiler flag
-require-explicit-sendable.