Tuesday, April 1, 2025

Xcode 16.3

Clang now defines TARGET_OS_* conditionals as built-in macros based on the provided target triple.
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Searching in the documentation viewer may start an indexing process which makes no progress. This may result in missing search results and increased CPU usage.
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Fixed: Foundation encoders/decoders user info dictionaries now require Sendable values. This may cause build errors even in the Swift 5 language mode in small edge cases where the userInfo property is set to a value like init(myCustomInitializer:) where the initializer is defined in an extension on Dictionary with a Value == Any constraint.
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Instruments 16.3 includes a new Processor Trace Instrument which uses hardware-supported, low-overhead CPU execution tracing to accurately reconstruct execution of the program.
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In Xcode when you are in a test context you are now able to query for your test plan name and scheme name in the environment with the keys XCODE_TEST_PLAN_NAME and XCODE_SCHEME_NAME.
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xcodebuild supports constraining the tests run through tests actions by tags. Use -only-testing-tags to include tests identified by a tags and -skip-testing-tags to omit tests identified by tags.

There are also lots of C++ and Swift/C++ improvements. It does not look like the issues with linking to certain frameworks on older versions of macOS (FB14667312) or calling async functions bridged from Objective-C (134442168) have been fixed yet.

Xcode Releases:

It is identical to RC2 that came out a couple of days ago.

Matt Massicotte (via Christian Tietze):

No, dynamic isolation is not bad.

But, I think we can also agree that static isolation is preferable. If you find yourself using dynamic isolation solely because it is a familiar pattern, that’s something to think about more deeply. Static isolation is a safer, clearer way to express what you need. That doesn’t mean you can always or even should start with it. Adopting concurrency will be a long process. Dynamic isolation is a very handy tool for getting there, I just don’t think it should typically be an end-state.

Rob Napier:

I’m wondering if there are changes to how DynamicActorIsolation works in Xcode 16.3. I’m seeing crashes due to running on a background thread that I don’t have with 16.2. The closure in question isn’t intended to be MainActor even though it’s defined in a View. With DynamicActorIsolation turned on, it seems to be getting MainActor assertions added, even if I mark it Sendable.

Paul Hudson:

If you upgraded to Xcode 16.3, be warned: there appears to be a simulator bug that causes network access to fail regularly. It doesn’t affect devices, just the simulator. You can work around it by using URLSession(configuration: .ephemeral) rather than URLSession.shared.

Previously:

Update (2025-04-02): Sean Heber:

Xcode 16.3 is seemingly refusing to remember the width of the canvas panel where SwiftUI previews live between tab switches and it is driving me bonkers and I’ve only had this version of Xcode a few hours.

C++ Programming Language Instruments Mac macOS 15 Sequoia Programming Swift Concurrency Swift Programming Language Testing Xcode