https://developer.apple.com/documentation/xcode-release-notes/xcode-16_3-release-notes

Xcode 16.3 Beta 3 Release Notes

Xcode 16.3 Beta 3 Release Notes
Update your apps to use new features, and test your apps against API changes.
Overview
Xcode 16.3 beta 3 includes SDKs for iOS 18.4, iPadOS 18.4, tvOS 18.4, watchOS 11.4, macOS Sequoia 15.4, and visionOS 2.4. The Xcode 16.3 beta 3 release supports on-device debugging in iOS 15 and later, tvOS 15 and later, watchOS 7 and later, and visionOS. Xcode 16.3 beta 3 requires a Mac running macOS Sequoia 15.2 or later.
General
Resolved Issues
Fixed: Clipboard Viewer is not included with Additional Tools for Xcode 16.3 beta. (142986262)
Known Issues
Using the -stack_size linker flag for an app bundle target may fail. Set ENABLE_DEBUG_DYLIB=NO as a workaround. (135877478) (FB15112909)
Downloads of the Predictive Code Completion model may look like they have failed right after they have almost reached 100% completion. (144245083)
Workaround: Retry enabling Predictive Code Completion from Xcode Settings or restart your computer.
Distribution
Known Issues
The app store has began to enforce all app groups prefixed with ‘group.’ are registered in a provisioning profile. During distribution, Xcode will fail to sign with the correct profile if you have used this machine to distribute before. This issue still occurs even if you have set the REGISTER_APP_GROUPS build setting, which ensures your project contains the correct app groups. (145875812)
Workaround: Before distributing your app validate on developer.apple.com that your app’s bundle id has the correct app group assignments. Next, remove related profiles from ~/Library/Developer/Xcode/UserData/Provisioning Profiles and $HOME/Library/MobileDevice/Provisioning Profiles. Finally, attempt to upload again and the app store should accept your app.
Foundation
Resolved Issues
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. (113200224)
Fixed: Passing Sendable Formatter subclasses across isolation boundaries in Swift may incorrectly cause compiler errors indicating that the type is not Sendable (144869425)
Frameworks
Resolved Issues
Fixed: Using the ManagedApp framework with the the iOS or visionOS SDK will fail to compile. (145665850)
Instruments
Resolved Issues
Fixed an issue where Call Tree view would occasionally cause application crashes. (146034535)
Playgrounds
Resolved Issues
Fixed: A playground that imports a module from a shared workspace may fail to run. (143923367)
Simulator
Resolved Issues
Fixed: In order to use iPad Air (M3) or iPad (A16) in the simulator with Xcode 16.2, download both the iPhone 16e, iPad Air (M3), and iPad (A16) Device Support and the iOS 18.3.1 Simulator Runtime from Xcode > Settings > Components. iPad Air (M3) and iPad (A16) are not currently compatible with iOS 18.4 beta 2. (143996162)
Testing and Automation
Known Issues
UI tests and unit testing using USES_XCTRUNNER=YES may see a UIKit warning about adopting scenes. This warning can be ignored. (142567138)
Updates in Xcode 16.3 Beta 2
AppIntents
Resolved Issues in Xcode 16.3 Beta 2
Fixed: OpenIntent required parameters incorrectly being marked as an error (143909972)
Apple Clang Compiler
Resolved Issues in Xcode 16.3 Beta 2
Fixed: In rare cases compiler generated code for Intel x86 processors may overwrite function parameters on the stack. (143354182)
CarPlay Simulator
New Features in Xcode 16.3 Beta 2
CarPlay Simulator allows you to go between simulated automaker backup camera UI and CarPlay via car button in CarPlay Simulator UI. (125863514)
Debugging
Resolved Issues in Xcode 16.3 Beta 2
Fixed: In some cases LLDB may not correctly handle breakpoints or symbolication of libraries loaded in simulator processes. (144655033)
Devices
New Features in Xcode 16.3 Beta 2
Xcodebuild now has a command to prepare debug symbols for an device without needing to have run Xcode. Pass -prepareDeviceSupport and a -destination predicate to prepare an unlocked and attached device. (124411614)
GameKit
Resolved Issues in Xcode 16.3 Beta 2
Fixed: Adding a new leaderboard to an existing leaderboard set that already contains a leaderboard won’t function as expected. (144418655)
Fixed: Game Progress Manager is now compatible with macOS, iOS, iPadOS, tvOS and visionOS. (145687441)
Instruments
New Features in Xcode 16.3 Beta 2
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. This tool provides metrics like duration, number of cycles, and instructions retired for every function executed on the CPU. Timeline in Instruments presents execution flame graph, while detail views provide aggregate-level data like Call Tree or aggregated metrics (min, max, count, sum), divided by function. Traces can be recorded using the new Processor Trace template on supported devices: M4 Mac, M4 iPad, and iPhone 16/16 Pro. Tracing on the device requires additional configuration in the System Settings. (131079807)
Interface Builder
Resolved Issues in Xcode 16.3 Beta 2
Fixed: iPhone 16e does not appear in the Interface Builder device bar. (144352490)
Simulator
Resolved Issues in Xcode 16.3 Beta 2
Fixed: In order to use iPhone 16e in the simulator with Xcode 16.2, download both the iPhone 16e, iPad Air (M3), and iPad (A16) Device Support and the iOS 18.3.1 Simulator Runtime from Xcode > Settings > Components. iPhone 16e is not currently compatible with iOS 18.4 beta. (143996070)
Fixed: Xcode and LLDB encounter a delay of 30 seconds or more when starting a debug session for a process in a Simulator device. The debug console may display a warning stating that LLDB is unable to read from the host’s in-memory shared cache. During this delay, the simulated app will remain invisible or unresponsive. (145105465)
Fixed: Simulator runtimes may complete download but not show as usable from Xcode. (145242743)
Fixed: Incorrect icons are used for recently released iPad hardware in Xcode’s run destination menu and devices window. (145902433)
Source Editor
Resolved Issues in Xcode 16.3 Beta 2
Fixed an issue where expanding short macros inside the Source Editor may crash Xcode. (142656554)
Swift/C++ Interoperability
Resolved Issues in Xcode 16.3 Beta 2
Fixed: Xcode targets using Swift/C++ interoperability and having a deployment target of less than iOS 16 or tvOS 16 may not build for iOS or tvOS simulators. (141232269)
Testing and Automation
New Features in Xcode 16.3 Beta 2
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. (132936523)
When using a Swift.org toolchain, Xcode now prefers the copy of Swift Testing in that toolchain for building and running tests if one is available for the current platform. (144709027) (FB16490332)
Resolved Issues in Xcode 16.3 Beta 2
Fixed: Swift Testing and XCTest tests and suites written in Swift which are surrounded by #if conditions may not be shown in Xcode’s Test navigator or source editor. (117387631)
Fixed: Resolved an issue where Swift Testing may produce spurious warnings when try #require() is used to cast a value of class type to another class. (144624300)
Updates in Xcode 16.3 Beta
General
Resolved Issues in Xcode 16.3 Beta
Fixed: Using LD_CLIENT_NAME could cause a runtime crash where the debug dylib could not be found on some platforms. The workaround setting ENABLE_DEBUG_DYLIB=NO should no longer be necessary in this case. (144577495)
Apple Clang Compiler
New Features in Xcode 16.3 Beta
Clang now defines TARGET_OS_* conditionals as built-in macros based on the provided target triple. This extension can be disabled with the flag -fno-define-target-os-macros. (111414452)
You can now annotate C++ methods using API Notes. (131387880)
You can now annotate C++ classes declared within other classes using API Notes. (132083354)
The default C++ language standard for the Apple Clang compiler is now C++14 with GNU language extensions.
The following C++26 features have been implemented:
Unevaluated strings (P2361R6)
constexpr cast from void*(P2738R1)
On the ignorability of standard attributes (P2552R3)
User-generated static_assert messages (P2741R3)
Placeholder variables with no name (P2169R4)
Template parameter initialization (P2308R1)
Remove Deprecated Arithmetic Conversion on Enumerations (P2864R2)
Clarifying rules for brace elision in aggregate initialization (P3106R1)
Pack Indexing (P2662R3)
= delete("should have a reason"); (P2573R2)
Attributes for Structured Bindings (P0609R3)
Disallow Binding a Returned Glvalue to a Temporary (P2748R5)
Trivial infinite loops are not Undefined Behavior (P2809R3)
Deleting a Pointer to an Incomplete Type Should be Ill-formed (P3144R2)
Ordering of constraints involving fold expressions (P2963R3)
The following C++23 features have been implemented:
Deducing this (P0847R7)
Change scope of lambda trailing-return-type (P2036R3)
Relaxing some constexpr restrictions (P2448R2)
A type trait to detect reference binding to temporary (P2255R2)
Static and explicit object member functions with the same parameter-type-lists (P2797R0)
The following C++20 features have been implemented:
Class types as non-type template parameters (P0732R2)
Immediate functions (consteval) (P1073R3) (144371212)
C++ Standard Library
New Features in Xcode 16.3 Beta
The following C++26 features have been implemented:
Concatenation of strings and string_views (P2591R5)
Member visit (P2637R3)
Printing Blank Lines with println (P3142R0)
Interfacing stringstreams with string_view (P2495R3)
Add tuple protocol to complex (P2819R2)
The following C++23 features have been implemented:
Pipe support for user-defined range adaptors (P2387R3)
out_ptr - a scalable output pointer abstraction (P1132R8)
std::ranges::contains_subrange (std::ranges::contains has been implemented in a previous release) (P2302R4)
ranges::find_last(), ranges::find_last_if(), and ranges::find_last_if_not() (P1223R5)
Poison Pills are Too Toxic (P2602R2)
The following C++20 features have been implemented:
The Mothership has Landed: Adding <=> to the Library (P1614R2)
Symmetry for spaceship (P0905R1)
std::atomic_ref (P0019R8)
Add wait/notify to atomic_ref<T> (P1643R1)
Missing constexpr in std::optional and std::variant (P2231R1)
Performance improvements:
The performance of growing std::vector has been improved for trivially relocatable types.
Many types are considered trivially relocatable now, including std::vector and std::string.
The performance of std::ranges::fill and std::ranges::fill_n has been improved for std::vector<bool>::iterators, resulting in a performance increase of up to 1400x.
The std::mismatch and std::ranges::minmax algorithms have been optimized for integral types, which can lead massive performance improvements (up to 100x).
The std::set_intersection and std::ranges::set_intersection algorithms have been optimized to O(log N) instead of O(N) in certain best-case scenarios.
std::stable_sort uses radix sort for integral types now, which can improve the performance up to 10x in the best case. (144568843)
Deprecations in Xcode 16.3 Beta
The following items have been deprecated or removed:
Implemented the “Remove Deprecated strstreams From C++26” paper (P2867R2). The _LIBCPP_ENABLE_CXX26_REMOVED_STRSTREAM macro has been added to restore the old behavior. This compatibility macro will be removed in a future release.
Implemented the “Remove wstring_convert From C++26” paper (P2872R3). The _LIBCPP_ENABLE_CXX26_REMOVED_WSTRING_CONVERT macro has been added to restore the old behavior. This compatibility macro will be removed in a future release.
Implemented the “Disallow User Specialization of allocator_traits” paper (P2652R2).
The base template for std::char_traits has been removed. If you are using std::char_traits with types other than char, wchar_t, char8_t, char16_t, char32_t or a custom character type for which you specialized std::char_traits, your code will stop working. The Standard does not mandate that a base template is provided, and such a base template is bound to be incorrect for some types, which could previously cause unexpected behavior while going undetected.
LWG3430 has been implemented which disallows implicit conversion of the source arguments to std::filesystem::path when constructing std::basic_*fstream. This effectively removes the possibility to directly construct a std::basic_*fstream from a std::basic_string_view, a input-iterator or a C-string, instead you can construct a temporary std::basic_string. This change has been applied to C++17 and later.
libc++ no longer supports std::allocator<const T> and containers of const-qualified element type, such as std::vector<const T> and std::list<const T>. This used to be supported as an undocumented extension. If you were using std::vector<const T>, replace it with std::vector<T> instead. The _LIBCPP_ENABLE_REMOVED_ALLOCATOR_CONST macro can be defined to temporarily re-enable this extension. This compatibility macro will be removed in a future release. To assist with the clean-up process, consider running your code through Clang Tidy, with std-allocator-const enabled.
libc++ no longer supports relational comparison for std::chrono::weekday. The relational comparison operators were provided as an undocumented extension. If you were using relational comparison on std::chrono::weekday, compare the results of c_encoding() or iso_encoding() instead. The _LIBCPP_ENABLE_REMOVED_WEEKDAY_RELATIONAL_OPERATORS macro can be defined to temporarily re-enable this extension. This compatibility macro will be removed in a future release.
The C++20 synchronization library (<barrier>, <latch>, std::atomic::wait, etc.) has been deprecated in language modes prior to C++20. If you are using these features prior to C++20, please update to -std=c++20. In a future release, the synchronization library will become unavailable in language modes prior to C++20.
The operators in the rel_ops namespace have been deprecated as a part of the paper P0768R1 “Library Support for the Spaceship (Comparison) Operator”.
The _LIBCPP_ENABLE_NARROWING_CONVERSIONS_IN_VARIANT compatibility macro that changed the behavior for narrowing conversions in std::variant has been removed.
The _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS and _LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_VOID_SPECIALIZATION compatibility macros have been removed.
The _LIBCPP_ENABLE_CXX17_REMOVED_FEATURES and _LIBCPP_ENABLE_CXX20_REMOVED_FEATURES compatibility macros have been removed.
Several incidental transitive includes have been removed from libc++. If you see errors related to missing std:: entities in your code after upgrading, ensure you have all required includes. (144887966)
Debugging
New Features in Xcode 16.3 Beta
Rendering of LLDB and Swift REPL error diagnostics is improved. Inline diagnostics can now directly point to command input without echoing the command first. 
 (138057894)
GameKit
New Features in Xcode 16.3 Beta
GameKit provides social-gaming network features that you use to enhance engagement in your game. Starting in Xcode 16.3, you can update your game’s leaderboards and achievements locally in Xcode. Use Xcode to pull your existing configuration from App Store Connect. Once you’ve made changes, you can push updates to App Store connect. You can also test your leaderboards and achievements in Xcode by enabling Debug Mode. Update the progress for a leaderboard or achievement and the system sends an update to your app so you can verify that the leaderboard or achievement changed as expected in real time. (110809856)
Instruments
New Features in Xcode 16.3 Beta
Call Trees now allow for listing all the samples aggregated to a node by context clicking on it and selecting ‘Show (Self) Samples’ (89381694)
Double clicking on an interval in the timeline while holding Option modifier will now filter and zoom-in to the interval location. (140099146) (FB15872554)
Clicking on a selected track will now expand it’s height to fit all the plots. (143853314)
Resolved Issues in Xcode 16.3 Beta
Fixed: Gesture handling for timeline events has been simplified. Single click now selects an item, while double click sets the inspection range of a trace to interval location. Triple click gesture handling has been removed. (91116149)
Fixed: Threads are no longer named based on backtraces attributed to that thread. This improves performance of Instruments and ensures consistency of thread names with other tools. (107272376)
Fixed an issue where xctrace would crash when recording CPU Counters template containing unavailable PMU events. (127001356) (FB13752225)
Fixed an issue where Allocations Instrument would misattribute source location of an allocation in the disassembly view. (127261727)
Fixed: Improved collapsing behavior of the Heaviest Stack Trace by ensuring that prominent frames with source information are no longer hidden. (136160536)
Fixed: Source Viewer performance has been improved and will no longer be slower than the initial load of the Call Tree view. (138136953)
Deprecations in Xcode 16.3 Beta
Removed support for profiling Notification Center Widget Extensions. (138192293)
Localization
New Features in Xcode 16.3 Beta
The String Catalog Editor now displays the number of strings in the file (or the number of strings that match the active filter). (122523913)
The String Catalog Editor now emits errors for more cases of contradictory format specifiers in varied strings. (128285700)
Resolved Issues in Xcode 16.3 Beta
Fixed non-determinism in choosing string values when multiple targets share an InfoPlist.strings file. Additionally, more info plist keys may be extracted to InfoPlist.xc/strings files automatically. Keys such as CFBundleDisplayName will now be auto-extracted as “Don’t Translate” when they come from targets such as frameworks that typically do not display these values in the UI. (116603462)
Fixed: Format specifiers in String Catalog strings now have simplified rules for inferring argument numbers in order to avoid unexpected crashes at runtime. In most cases, the string “%@ has %lld books” is inferred to be equivalent to “%1$@ has %2$lld books”. In Xcode 16.3, this also applies to plural variations. An exception continues to be plural variations inside substitutions, which begin assigning implicit argument numbers starting with the substitution’s own assigned argument in the Attributes Inspector. To change behavior away from the default, use explicit argument numbers in strings (e.g. “%1$@ has %2$lld books”). (128509959)
Fixed: It is now a formal build error to place an xcstrings file inside an lproj directory. mul.lproj is an exception to this, since Xcode uses it to track String Catalogs associated with IB files in Base.lproj. (133238564)
Fixed: String Catalogs now remember sort order per editor. (133752416) (FB14780987)
Fixed: Xcode now remembers the preferred column order for String Catalogs. (135439846) (FB15056367)
Fixed: Jumping from strings in source code to entries in the String Catalog now also works for App Intent / Shortcut phrases. (138472363)
Fixed: Within buildable folders, .strings files are now properly grouped together with same-named Base-localized IB files and will share target membership. (139114187)
Fixed: Resolved various issues that could occur when localizable files are inside buildable folders. (139114232)
Predictive Code Completion
Resolved Issues in Xcode 16.3 Beta
Fixed: Expanded the amount of in-project context that will be used when providing suggestions for Predictive Code Completion. (141363041)
Fixed an issue that could cause some suggestions in Predictive Code Completion to contain unnecessary symbols or placeholder text. (141952159)
Previews
Resolved Issues in Xcode 16.3 Beta
Fixed: In some project configurations, switching between Previews in different targets could show an error in the canvas that would not go away until a manual build was triggered. (138953897)
Fixed: Previews for a file in a static library or static package target could fail if they depended on a dynamic library or framework also built in the same project. (140224924) (FB15892343)
Fixed: SWIFT_ENABLE_OPAQUE_TYPE_ERASURE is now off by default for all debug builds. If you were previously turning it off in your project, you can remove that override. Previews now enables this selectively and recompiles the edited file with this setting only when running a preview. (140442875)
Fixed: Previews is only able to work for unoptimized builds compiled with -Onone and SWIFT_COMPILATION_MODE=incremental, which are the default for debug builds. Previews now provides better error messaging and instructions if you attempt to Preview in a file that is built with different settings. (140803231)
Fixed: Previews in static libraries that used @availability annotations would fail with a symbol not found error. This should now be resolved but if you continue to experience this please file a new feedback with fresh diagnostics since we’ve added new logging for triage. (140898299) (FB16037528)
Fixed: Previews offers two great benefits: a way to quickly see a configuration of a view without needing to build and run, and an execution environment for rapidly verifying changes. ‘Automatically Refresh Previews’ provides the fastest execution environment. Disabling it will fall back to a slower execution environment that may work for your project configuration, while providing a speed benefit that should still be significantly faster overall than build and run. If disabling Automatically Refresh Previews resolves issues you experience in previews for your project configuration, please file a feedback with fresh previews diagnostics before and after toggling the setting. We’ve added new logging to help further triage issues. (141724767)
Fixed: In some project configurations on-device Previews could fail if you switched between files until you manually triggered a project rebuild. (142443659)
Fixed: In some project configurations Previews would show a blank canvas instead of a helpful error message if there were no previews found for this target. Remember to check that your preview is built for the run destination you are targeting if you use conditional compilation to hide previews.
If you double checked your configuration and still believe the preview should be found, please file a feedback. If possible, also please include a simplified reproduction of the problem to help triage your specific setup. New diagnostics and logging have been added so fresh feedback will include important details. (143507303)
Fixed: As a general note, in addition to other correctness fixes in Xcode and our paired OS releases, diagnostics collection has been improved to help resolve remaining issues with the previews pipeline. If you have experienced timeouts or strange crashes in your code when using the new Previews execution engine, please see if your issues are resolved. If not, please file new feedback with fresh diagnostics to provide the latest information. (143628687)
RealityKit
Resolved Issues in Xcode 16.3 Beta
Fixed: EntityAction, ForceEffectProtocol, and RealityRenderer methods that take closures are now marked as always executing on the main actor. Closures passed to EntityAction and ForceEffectProtocol are now marked as always executing on the main actor, and closures passed to RealityRenderer are now marked as executing without isolation. (133462227)
Simulator
Resolved Issues in Xcode 16.3 Beta
Fixed: Simulator no longer discards key up events for keys when the command key is held. (63086391) (FB7697257)
Fixed: simctl now supports –json-fd and –json-output command line arguments for directing JSON output to a destination other than stdout. (141441027)
Source Editor
New Features in Xcode 16.3 Beta
Editing JSON in Xcode now supports JSON5 syntax, including comments. (117205049)
Resolved Issues in Xcode 16.3 Beta
Fixed an issue that sometimes caused horizontal scroll bars to be hidden from view when the Minimap was enabled. (102106707)
Fixed an issue where Code Completion may present a symbol as from the incorrect framework after using Jump to Definition. (137079926)
Swift/C++ Interoperability
New Features in Xcode 16.3 Beta
You can now call C++ functions that use char8_t type from Swift. (39988329)
You can now use Swift static variables from C++. (115564118)
You can now use Swift structs and enums declared within other Swift types from C++. (118793469)
C++ Standard Library Hardening now takes effect for Swift usages of C++ types such as std::span. (126570011)
Swift overlay for the C++ standard library is now available when targeting Mac Catalyst. (126938813)
C enums now automatically conform to Swift Hashable protocol. (129713687)
You can now conform C++ types to Swift protocols using the new SwiftConformsTo: API Notes attribute. (131388824)
You can now access Swift subscript operators with multiple parameters from C++. (133539699)
You can now initialize a C++ std::map or std::unordered_map from a Swift Dictionary. (133691563)
Mutable C++ containers such as std::vector now automatically conform to Swift MutableCollecton. (134531554)
C++ std::string now conforms to Swift Comparable. (135184553)
You can now annotate C++ functions and methods that return SWIFT_SHARED_REFERENCE types with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED to explicitly define the ownership convention when called from Swift. The Swift compiler will now emit a warning for such C++ functions and methods that are not annotated with these ownership conventions. (135306908)
C++ std::set and unordered_set now conform to Swift ExpressibleByArrayLiteral. (137126325)
C++ std::map and unordered_map now conform to Swift ExpressibleByDictionaryLiteral. (137126474)
You can now initialize a Swift String from a C++ std::string_view. (138417835)
You can now annotate C++ functions and methods returning SWIFT_SHARED_REFERENCE types with SWIFT_RETURNS_RETAINED or SWIFT_RETURNS_UNRETAINED using the new SwiftReturnOwnership: API Notes attribute. Set its value to retained or unretained, respectively, to explicitly specify the ownership convention of the returned value. (141007510)
Compiler now produces an error when a public member of a C++ type and a private member of the type are imported into Swift with the same name. For example, a private field name and a method getName() annotated as SWIFT_COMPUTED_PROPERTY will have a name conflict when they are imported into Swift and will result in an error. SWIFT_NAME attribute can be used to import them differently. (144736093)
Test Report
New Features in Xcode 16.3 Beta
The Test Report now displays XCUIElementQuery suggestions for UI elements selected using the Automation Explorer at a point of test failure. (131473847)
Testing and Automation
New Features in Xcode 16.3 Beta
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. (66632690)
When a Swift Testing issue is recorded from an unknown context, such as a detached Task, the error message shown in Xcode now includes a description of the issue and the backtrace indicates where it occurred, for easier diagnosis. (131564494)
The XCTest APIs related to UI automation testing have been moved to a new, standalone framework named XCUIAutomation. XCTest re-exports XCUIAutomation so import XCTest continues to import the APIs of both frameworks. You can use XCUIAutomation APIs from XCTest tests and any helper or utility functions they call. (137059728)
Swift Testing now includes Test Scoping Traits, a set of APIs for defining custom traits which can run code before or after tests or suites they’re applied to. For example, you can implement a trait which assigns a task local value for the duration of a test:
   struct MockAPICredentialsTrait: TestTrait, TestScoping {
     func provideScope(for test: Test, testCase: Test.Case?, performing function: @Sendable () async throws -> Void) async throws {
       let mockCredentials = APICredentials(apiKey: "...")
       try await APICredentials.$current.withValue(mockCredentials) {
         try await function()
       }
     }
   }
   
   extension Trait where Self == MockAPICredentialsTrait {
     static var mockAPICredentials: Self {
       Self()
     }
   }
   
   @Test(.mockAPICredentials)
   func example() {
     // ...validate API usage, referencing `APICredentials.current`...
   }
See the proposal SWT-0007 for more details. (138099506)
#expect(throws:) and #require(throws:) now return the error that was thrown so that tests can inspect them further. (138235250)
Swift Testing now allows specifying a range of expected counts when calling confirmation(). (138499457)
Resolved Issues in Xcode 16.3 Beta
Fixed: XCTAttachment does not support attaching directories on iOS, watchOS, tvOS, or visionOS. (31157453)
Fixes an issue with running parallel Tests on macOS run destinations where it never finishes. (125369004)
Fixed: The xcodebuild flags -only-testing and -skip-testing now accept identifiers for Swift Testing tests and suites. (127329947)
Fixed an issue when pressing up/down/left/right hardware keyboard buttons in text views. (132717800) (FB14538574)
Fixed: XCTest UI Recording has been enhanced to offer a more refined code generation process when capturing application events. This feature now also allows for recording any application, not just the application under development. XCTest UI Recording is available for all platforms except for visionOS. (138064709)
Fixed: If an error is thrown by the prepare(for:) method of a custom Swift Testing trait type, the test runner now records the error as an issue instead of crashing. (140813092)
Xcode Cloud
New Features in Xcode 16.3 Beta
You can now share environment variables across multiple workflows and use them in your custom build scripts. Learn about Shared Environment Variables. (76150704)
xcresulttool
New Features in Xcode 16.3 Beta
In Xcode 16, xcresulttool introduced new commands, including: get test-results summary, get test-results tests, get test-results test-details, get test-results activities, get test-results insights, get build-results, get log, export attachments, and export metrics. Please run xcresulttool help <command> [<subcommand>] to get more details for these commands as well as the output format. In Xcode 16.3 there are the following additions:
Command that outputs performance metrics in JSON format: xcresulttool get test-results metrics --path <path> [--compact] [--test-id <test-id>] A test identifier (test-id) can be used to specify a Test Case or a Test Suite. All the available metrics will be included if no test-id is provided.
Command that outputs information about the available content in a .xcresult bundle, including code coverage, diagnostics, test results and logs: xcresulttool get content-availability --path <path> [--compact]
Command that compares the content of two result bundles. Optional flags allow you to customize the outputted results: xcresulttool compare <comparison-path> ... --baseline-path <baseline-path> [--summary] [--test-failures] [--tests] [--build-warnings] [--analyzer-issues]
All the commands that use test-id as an argument now accept both testIdentifier and testIdentifierURL values. Identifier URL (testIdentifierURL) is a recommended way of identification for Test Cases and Test Suites as it resolves identifier ambiguity across multiple testing targets. (129712945)
Deprecations in Xcode 16.3 Beta
Some parts of xcresulttool API are deprecated and will be removed in the future. Upon removal they can be used with --legacy flag provided. Please use the new commands from above instead. List of deprecated commands:
 xcresulttool get [object] --legacy --path <path> [--id <id>] [--version <version>] [--format <format>]
 xcresulttool export [object] --legacy --path <path> --output-path <output-path> [--id <id>] --type <type> [--version <version>]
 xcresulttool graph --legacy --path <path> [--id <id>] [--version <version>]
(144104308)