Release Notes For Xcode 9 Beta 2 5l3v

= ), typedef, enum, or enumerator declarations that are declared in a class template will rename their uses whose qualifier includes an implicit template instantiations. (32325459) The “Extract Function” and “Extract Method” refactoring operations can be initiated from within a macro argument. (32379522)

g and Distribution When you build and run and encounter a provisioning issue, Xcode won’t prompt you to a device, revoke a certificate, or a provisioning profile if these repairs are necessary. (32366863)

 Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea Server

Xcode Server will not report integrations as being successful if they fail to generate the archive. (31957210)

Simulator Simulator.app menu keyboard shortcuts no longer get delivered to the device. (32094433) Accessibility elements in Simulator runtimes are not flipped vertically. (31948245) Simulator.app properly saves the location of windows between launches. (32303682) Clicking buttons in the Apple TV Remote in Simulator will not cause the window to move upward. (32314303) Booting simulators in Virtual Machines with less than 4G of memory will not result in an error dialog box. (31871122) Simulator will not fail in OpenCL when running on pre–2013 Mac hardware or Virtual Machines. (32293108) log collect can be executed in Simulator as a standard . (32531154)

UI Testing works in tvOS 11.0. (32371700) App launch will not time out in simulated watchOS 4.0 devices. (32314337) The launchctl command is available in Simulator. (32445544) /usr/bin/defaults is available in Simulator. (32628360)

Activating Siri in a simulated tvOS device will not cause the device to restart. (32284246)

Documentation Viewer ing sample code in the documentation viewer once again works in Xcode 9 beta. (32538902)


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Xcode 9 beta 2 Relea Known Issues in Xcode 9 beta 2 – IDE General Deleting a project file from your disk while that project is open in Xcode will cause a crash. (31849539) Application installation can fail with “Failed to acquire termination assertion when installing placeholder for BUNDLE-IDENTIFIER” (32339359) Workaround: Exit the application and try again. This should only occur if the app is being installed while it is active. s using a phone number as the Apple ID cannot sign in to Xcode. (32917618)

Source Editor The source editor in this beta version of Xcode 9.0 doesn’t yank.. (30083567) When recording UI tests in the Xcode source editor, tokens may not correctly resolve to source code that can compile. (29391589) Xcode 9’s new source editor does not yet code folding. (29396003) Xcode 9’s new source editor does not yet discontiguous or columnar selection. (30738532) Xcode 9’s new source editor does not yet printing. (30852651) Xcode 9’s new source editor does not yet displaying and navigating to issue notes. (31491175) Xcode 9’s new source editor does not yet render invisible characters. (7612691) Scroll position is not preserved in the Source Editor when switching to or from the Version Editor modes (Comparison, Blame, or Log). (30400751) Editing a multi-line string in Swift may cause lines within the string and later in the file to lose syntax coloring until the string is valid and the affected lines are modified. (32148117)


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Xcode 9 beta 2 Relea Interface Builder

Using a Swift image literal within prepareForInterfaceBuilder() causes the IBDesignablesAgentCocoaTouch to crash, because live views are compiled in a different bundle. (28676479) Workaround: Use UIImage(named:inBundle:compatibleWithTraitCollection:) for all image lookups, and specify the bundle for the calling class. Simulated Metrics overrides other than Freeform size have no effect on the canvas. (28806592) Opening a tvOS storyboard can have a severe impact on system performance due to excessive memory use by the IBAppleTVTool. (32542011) Workaround: Open a terminal and run the command: defaults write com.apple.dt.Xcode IBLaunchPlatformToolsWithLimitedLaunchdJobs -bool NO, and then relaunch Xcode. In tvOS Interface Builder documents, the canvas always renders in light mode, even when switching to dark mode. (32543311) The default autolayout margins for tvOS are incorrect. (32393914)

Asset Catalog Jpeg assets in asset catalogs are not found on iOS 10 or earlier for apps built with Xcode 9. API calls for accessing the image such as UIImage.imageNamed: return nil. (32524123) Workaround: Use png resources or limit app testing to devices running iOS 11 or later.

Debugging You may see two entries for the same Apple TV devices in the Run Destinations list or the Devices window. (32118508) Workaround: On the Apple TV, press the Menu button to leave the Remote App and Devices settings screen. You may experience connection issues with wireless development immediately after detaching your device from USB. (31966846) Workaround: Enable airplane mode on your device for 10 seconds and then disable airplane mode to re-establish your connection. Entering the wrong pin in the Devices Window when wirelessly pairing Apple TV will continue to request a new pin. (32408330) Workaround: Click on the pin code and press the delete key.  Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea Symbols may not be ed from devices paired over the network. (31304833)

Workaround: Before enabling wireless development, plug in the device and wait for it to finish preparing debugger . The value of of an NSMutableSet aren’t shown when the variable is turned down in the Xcode Variables View, as they are for an NSSet. This occurs when debugging on macOS 10.13, iOS 11, tvOS 11, and watchOS 4. (32307219) Workaround: Control-click the variable in the Variables View to and choose ‘Print Description of’ to print the NSMutableSet in the Xcode Debug Console, or use the po command at the debugger prompt. No standard out content is printed to Xcode’s console for a process whose launch was waited for prior to being attached by the debugger. (10275573) Debugged processes may hang on launch if the “Use Terminal” console option is used. (31707955) Workaround: Select “Use Xcode” in the scheme options. Watch development may not work when using wireless development. (32341381) Workaround: Attach the paired iPhone via USB. The first time you run a Complication from Xcode in Simulator it may continually exit the first time you configure that Complication. (29858029) Workaround: Re-run the scheme in Xcode. Sometimes when debugging a Messages Extension on a device, Messages doesn’t automatically start a new conversation and start using the extension. (31096267) Workaround: Manually start a new conversation and select the extension. After building and running a Watch app from Xcode your app might not install, launch, and attach. (32180669) Workaround: Reboot Apple Watch and iPhone, then reconnect your iPhone to your Mac to show the trust dialog on Apple Watch. It may take a few minutes for the trust dialog to appear after rebooting the device and connecting it to the Mac. If a project uses any frameworks that have code written in Go, it will not be possible to run or debug the app. (31451900) Workaround: Use Xcode 8.2 or remove the dependency on such frameworks.


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Xcode 9 beta 2 Relea When debugging processes that use Swift, the Xcode Memory Debugger, the Leaks instruments, and ‘leaks’ command may report incorrect (false-positive) leaks of small malloc blocks, and may confuse strong versus weak references. (29780048) GPU performance counters are disabled on Nvidia GPUs. (32497239) In the GPU Frame Debugger, Frame captures using nested argument buffers (such as argument buffers encoded to another argument buffer) are not ed. (31245702) In the GPU Debugger, Argument buffers don’t have the correct formatting in the buffer viewer. (31254766) In the GPU Frame Debugger, the filters will always filter for ANY when there multiple filter , regardless of what is selected. (32455262) In the GPU Frame Debugger, Argument encoders created before the start of a frame capture will crash the app while capturing. (32415645) Workaround: Create argument encoders within the captured workload or release them before capturing. Changes to a breakpoint’s options (conditions, ignore count) will not have any effect if they are made after the breakpoint has been disabled. (32384113) Workaround: After changing breakpoint options, toggle the breakpoint to have the conditions take effect.


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Xcode 9 beta 2 Relea Playgrounds

Live views for iOS and tvOS playgrounds may appear distorted on macOS 10.13. (32386253) The liveTouchBar property of Playground is not ed. (31073754) The live view of iOS and tvOS playgrounds may fail to display when the playground is first run. (32358116) Workaround: Stop playground execution and rerun. Xcode 9’s new source editor does not yet resizing the playgrounds results area. (32358302) Dragging and dropping auxiliary resources into the “Sources” or “Resources” folders of a playground inside the structure navigator will fail if the directory does not exist on disk. (32359267) Workaround: Manually create a “Sources” or “Resources” directory inside the playground prior to dragging and dropping resources into the auxiliary folders. macOS playground execution may hang in the “Running” state with no results produced. This is more prevalent when changing pages. (32429211) Workaround: Stop playground execution and rerun. If issue persists, close and reopen Xcode. The New playground page contextual menu item does not create a new page. (32164810)

Testing xcodebuild test can intermitently fail with ’Error Domain=IDEPseudoTerminalDomain Code=5

“(null)”. (32358724) Workaround: Try the test again. xcodebuild test can intermitently fail with ’Error Domain=FBSOpenApplicationErrorDomain

Code=6 “Application failed preflight checks” (32446986) Workaround: Try the test again. xcodebuild test can intermittently fail with ‘Error Domain=DTServiceHubClient Code=–11

“unable to local DTServiceHub to bless simulator connection”’. (32354498) Workaround: Try the test again. xcodebuild test can intermittently fail with “Test runner for (null) will finish with error: Could

not obtain the bundle identifier for ‘…’”. (32658562)


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Xcode 9 beta 2 Relea Workaround: Try the test again.

xcodebuild test can intermittently fail with ‘DTXProxyChannel error 1’. (29500302)

Workaround: Try the test again. xcodebuild test can intermittently fail with ‘Domain=XCTestManagerErrorDomain Code=12

“Failed to get main window after 30 retries”’. (29122169) Workaround: Try the test again. xcodebuild test can intermittently fail with ‘Assertion failed: (staticHeader.header_magic ==

DTX_MESSAGE_MAGIC)’. (32670023) Workaround: Try the test again. xcodebuild test can intermittently fail with “Test operation failure: Lost connection to

testmanagerd”. (32445523) Workaround: Try the test again or reduce the number of devices being used to test in parallel. When using the new build system, performance testing baselines are treated as if missing which may result in spurious test failures. (31328476) Workaround: Use the legacy build system when running performance tests. UI tests that target the Touch Bar will not function on macOS 10.13. (32417038) cdtool is not found when running Xcode 8 after installing Simulator Runtime DLC from newer

versions of Xcode. (32683150) Workaround: Move aside the corresponding simruntime from /Library/Developer/CoreSimulator/Profiles/Runtimes and then restart CodeSimulatorService and other Xcode apps: sudo mkdir /Library/Developer/CoreSimulator/Profiles/Runtimes/Backup sudo mv /Library/Developer/CoreSimulator/Profiles/Runtimes/{,Backup/}iOS 10.3.simruntime sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService

Then restart Xcode, Simulator, Instruments, etc. UI Testing in tvOS 11.0 often fails with “Assertion Failure: App accessibility isn’t loaded” (32684493) Workaround: Run the test again.


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Xcode 9 beta 2 Relea xcodebuild test can intermittently fail with ’Error Domain=FBSOpenApplicationErrorDomain

Code=6 “Application failed preflight checks”. (27258971) Workaround: Try the test again.

Devices The Apple Watch button may be missing in Devices and Simulators window’s debug console. (32365458) Workaround: Disconnect and reconnect the device and toggle the Show/Hide button to get the button to show up.

Refactoring Some complex protocols may not be completely inserted when applying the fix for “Do you want to add protocol stubs?” For example, with Swift.Collection, where multiple associated types and requirements are inherited from parent protocols, may not work properly. (31078629) Workaround: Use the “Fix” button or manually add any additional missing protocol stubs. Constructors for locally defined types, such as a struct defined inside a function body, cannot be refactored. (31695776) When extracting a code snippet that uses locally defined types, for instance, an enum defined in a function body, the extracted function may use that type as a parameter, leading to uncompilable code. (32288968) References to declarations in static_assert statements are not renamed. (32323618) Renaming does not affect symbols found inside macro expansions. (31989492) Renaming Swift enum cases with associated values will not rename their argument labels. (32126363) Renaming a Swift class or protocol exported to Objective-C will not rename any references that use a forward @class declaration and do not include the generated MODULE-Swift.h header. (32275117) Workaround: #include the generated MODULE-Swift.h header in your .m file. Renaming a type that has the same name as the Objective-C header file it is declared in will rename all the #imports of that header except any that are inside the bridging header. (32305693) Workaround: Rename the #import in the bridging header manually.


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Xcode 9 beta 2 Relea Rename will not update references to an Objective-C ivar inside Interface Builder documents. (32314491) Renaming an Objective-C class property will not update the getter or setter class methods. Instance properties are not affected. (32376404) Workaround: Rename the getter and/or setter method separately. Renaming a call or reference to a memberwise initializer does not rename the corresponding member properties. (32383812) Workaround: Manually rename member properties from their definition or references. The extracted function or method might be placed between a comment that precedes the source function and a token that precedes the comment and that is on the same line as that comment. (32219809) When renaming files, Xcode sometimes shows an error alert saying that the file has been saved by another application. (31968242) Workaround: Click the alert’s “Save Anyway” button to correctly save the renamed file. Renaming the Objective-C setter for a property causes a crash. (32313554) Workaround: Rename from the property declaration or a reference to it, the getter, or associated instance variable. Renaming Swift IBActions sometimes incorrectly renames occurrences in Interface Builder files. (32316577) Workaround: Rename any incorrect occurrences from the editor. Undo does not work while renaming. (32429491) Workaround: Manually edit the new name, or use Cancel.

Swift Migration References to the AVCaptureDevice.defaultDevice(withMediaType:) function are not renamed to AVCaptureDevice.default(for:). After migration, the compiler will error with: error: type 'AVCaptureDevice' has no member 'defaultDevice'

(32431567) Workaround: Manually rename the function.


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Xcode 9 beta 2 Relea Some APIs have changed to accept [NSAttributeKey: Any] dictionaries instead of [String: Any], such as NSString.size(withAttributes:) and NSString.draw(at:, withAttributes:). These changes may produce errors after migration is completed. (32431618) Workaround: Change the type to match the expected parameters in the variable declaration. After migration, invalid references to notification names such as .NSTableView.selectionDidChangeNotification or NSNotification.Name.NSTableView.selectionDidChangeNotification may result in

errors such as: error: type 'NSNotification.Name' has no member 'NSTableView'

(32466196) Workaround: To fix the error, remove the leading dot or leading NSNotification.Name. prefix. After migration, the compiler may error with: error: value of type 'Substring' has no member 'rangeOfCharacter'

(32431949) Workaround: Wrap the value, on which rangeOfCharacter is called, with String(…). Some APIs that previously accepted a String parameter have changed to accept an enum type of a raw String type in Swift 4. In some situations, the migrator does not add code to properly wrap the String value. (32431165) Workaround: Wrap the string value with the expected enum type, such as: TheEnumType(rawValue: <string value>)

The migration may not properly convert APIs which changed from an optional String to an enum, producing errors such as: error: cannot convert value of type 'String?' to specified type '<SomeEnumType>'

(32431736) Workaround: Add code to wrap the String value with: SomeEnumType(rawValue: ..)


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Xcode 9 beta 2 Relea The migrator does not properly distinquish between single-tuple and multiple-argument function types as described in SE–0110, causing additional mismatched type errors with the closure types that are ed to Standard Library functions expecting tuple objects. (32431899) Workaround: Manually fix the closure types to accept values of tuples instead of separate argument values. When using a String to index a Dictionary that has NSAttributedStringKey as key, the compiler may return an error of the form: error: ambiguous reference to member 'subscript'

(32432013) Workaround: Manually wrap the key object with NSAttributedStringKey(rawValue: ..) The migrator does not properly handle cases where an API changes nullability and the right side of an if let statement becomes non-optional. This will produce errors such as: error: initializer for conditional binding must have Optional type, not ' '

(32476453) Workaround: Change the if let statement to make it an assignment with let instead. When using $0 and $1 in a closure that is ed to a function expecting a closure with a single tuple argument, the compiler may error after migration with: error: closure tuple parameter '(TYPE, TYPE)' does not destructuring with implicit parameters

(32489893) Workaround: Change $0 and $1 references to $0.0 and $0.1 respectively. After migration, the compiler may return an error of the form: error: 'Integer' is unavailable

(32432481) Workaround: Replace Integer with BinaryInteger. When ing a closure with a single underscore argument ({ _ in …}) to a function expecting multiple arguments, after migration the compiler may return an error of the form:


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Xcode 9 beta 2 Relea error: cannot convert value of type '(_) -> ()' to expected argument type

(32301091) Workaround: To fix the error, change the single argument to the correct number of arguments such as { (_,_) in …} When ing a closure to map with two function arguments, after migration the compiler may return an error of the form: error: 'map' produces '[T]', not the expected contextual result type ' '

(32432752) Workaround: Change the closure signature to accept a tuple argument of two elements when using map. When comparing a String to a string_enum type, the migrator may not properly adjust code to for SDK changes. The compiler may return an error of the form: error: binary operator '==' cannot be applied to operands of type 'NSToolbarItem.Identifier' and 'String'

(32432253) Workaround: Change the side of the comparison with the enum value to add .rawValue, so that the comparison works with strings on both sides.

Project Navigator Dragging the files into a project from the Finder may move or copy the underlying file. (31042020) Workaround: Hold down Command-Option while dragging to only create a reference, and leave the filesystem as is. Creating a “Group from Selection” may not associate the correct directory with the new group. (31684063) Workaround: Re-associate the group in the file inspector.


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Xcode 9 beta 2 Relea Source Control

When configuring or viewing your GitHub , Xcode may present a keychain prompt for an SSH key phrase. Click Allow or Always Allow to resolve this issue. (32017088) Changing a remote name in SCM inspector may crash Xcode. (32260828) Editing the address of a GitHub enterprise has no effect. (32300885) The new SCM history may load with no content. (32335760) Workaround: Force a reload of the view by clicking away and clicking back, or press Command-Control-W to reload. If an SSH key is configured in Xcode for a GitHub or GitHub Enterprise , and that key is removed from the file system, Xcode will not notice. (32355529) Xcode may not always prompt to trust the fingerprint of an SSH host(32444878) Workaround: Clone a repository from the same host over SSH using Git command-line tool

Build System The new build system may not define all of the environment variables that the standard build system defines when launching shell scripts. If the new build system is not supplying an environment variable which your scripts use, please file a bug with the name of the environment variable, the expected value you saw under the old build system, and a brief explanation about your usage of the variable. (24541618) The new build system does not yet building MLKit documents. (30177607) When using the new build system and using “DWARF with dSYM File” debugging information, the build may do unnecessary work to extract the dSYM on each build iteration, degrading build performance. (30668974) Workaround: Only enable “DWARF with dSYM File” for the “Release” configuration. With the new build system, switching between building the “Debug” and “Release” configuration of a project may result in unnecessary content rebuilding. (30924058) The new build system does not yet any of the Product > Perform Action > Compile, Analyze, Preprocess, or Assemble operations for single-files. (31072405) Interface Builder live views do not yet build using the new build system, and instead will use the old build system. (31433718)


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Xcode 9 beta 2 Relea The new build system does not yet building projects with Message Pack or Sticker Pack targets in them. (31508349) The new build system does not yet projects which have on-demand resources enabled. (31508570) When using the new build system, the total number of build tasks reported in the activity area may not be computed correctly, and will continue to increase during the build. (31855141) When using the new build system, some CopyPNG build steps may fail to build if there are no command line developer tools selected. (32386162) Workaround: Ennsure there are active tools by going to Xcode > Preferences > Locations > Command Line Tools and selecting a valid tool installation. When using the new build system, it is not possible to use the clean action in the IDE in a project or workspace that uses the “legacy” or “custom” build locations. (32296417) XIB and Storyboard files which use platform-specific naming conventions (e.g. “MyView~ipad.xib”) may cause the new build system to emit an “unable to build node” error. (32409101) Autocreated schemes are no longer available to xcodebuild until they’ve been marked as shared, or edited in any way, in Xcode. (9659122) The new build system does not yet any of the Edit > Convert > To Current Swift Syntax…, To Modern Objective-C Syntax…, or To Objective-C ARC… operations. (32464746) The new build system does not yet remove files, such as headers, produced by prior builds which are no longer produced by the current project configuration. (30961839) The new build system does not yet use of “Custom Paths” in build settings or shell script environment variables. (32615100) The new build system only copies the first localized resource in some situations. (32618863)

g and Distribution When exporting an ad-hoc or enterprise IPA, Swift symbol stripping will not be performed if you do not enable app thinning or recompile from bitcode. (31737836) Workaround: Enable app thinning or recompile from bitcode while exporting your app. Automatic provisioning may not work if you have ed multiple teams on your server, and you may be presented with an error about team credentials being incorrect. This will be resolved in an beta. (32426399)


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Xcode 9 beta 2 Relea SceneKit

SceneKit particles do not render in the SceneKit Editor when running on macOS 10.12 or earlier. (32352255)

Server Attempting to edit an Xcode Server bot may incorrectly display an error: “<Scheme> does not match this workspace” even though it does. (31957021) Workaround: Click “Cancel” to dismiss the dialog. Xcode Server will sometimes report ‘Failed to build workspace with scheme .’ as an integration issue on the integration summary tab. (31957360) Workaround: Check the integration’s build logs for the actual error. Removing Server.app after configuring Xcode Server with Xcode 9 will stop the Xcode Server service. (31820819) Workaround: Do not remove Server.app, or after removing manually start Xcode Server again from the Server & Bots preference pane or using the xcscontrol command-line tool. Bots created in an earlier version of Xcode may appear to be configured to test in parallel but actually run tests sequentially. (32365638) Workaround: Edit the bot to toggle testing in parallel on and off again, and run a new integration.

Simulator Installation failures in Simulator may be reported incorrectly as IPC failures: “(ipc/mig) server died”. (31646737) Workaround: Open Console.app to read through the devices system log for more information on the root cause. The relevant error message should be logged by installd. IOSurface.framework is not yet present in the iOS Simulator SDK. (32160941) ATTR_CMNEXT_LINKID is not available when running Simulator on macOS 10.12.5 or earlier.

(32181698) Though volume and mute button events are sent to the simulated device, the volume is not adjusted. (32118558, 32117708) When running several simulators simultaneously you may exceed the maximum number of processes or maximum open file limits. If this happens attempts to start new processes or open  Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea more files will fail. You can recover by shutting down some simulators or closing open programs. macOS 10.13 automatically scales these limits based on available system memory. On earlier releases these limits are fixed values. These limits can be increased by using launchctl. For more information, choose Help > Simulator Help and navigate to Troubleshoot Simulator > Insufficient resources. (31179087) Booting many simulator devices in rapid succession can exhaust system resources without warning, preventing new processes from spawning. (31723508) Workaround: Close simulator windows or quit Simulator.app to shutdown devices for immediate recovery. Do not Force Quit Simulator.app as that will not shutdown the devices. For more information, choose Help > Simulator Help and navigate to Troubleshoot Simulator > Insufficient resources. Use of ATTR_CMNEXT_LINKID with the getattrlist(2) family of functions in the iOS, tvOS, and watchOS simulators requires macOS 10.12.6 Beta 2 or newer. (32226044) Some simulator devices may remain booted after running xcodebuild test. (32187594) Workaround: Run xcrun simctl shutdown booted after running xcodebuild test. Installing Xcode 9 on macOS 10.12.5 or earlier can cause Xcode 8’s Simulator, Interface Builder, and Playgrounds to stop functioning after launching Console.app. (31641958) Workaround: Update to macOS 10.12.6. Simulator windows fail to minimize when running on macOS 10.13 Beta. (32319153) Resizing a Simulator window will sometimes produce visible jitter or a flash to black. (32330985) Workaround: Disabling ‘Debug > Optimize Rendering for Window Scale’ should alleviate some of this problem, but it will cost more U usage. Simulator will crash on launch on older (circa 2010) Mac hardware, and may fail on some pre– 2013 Macs and on Virtual Machines. (32227092, 32293108) Workaround: You can force the use of OpenGL instea of OpenCL by setting the following defaults option: defaults write com.apple.CoreSimulator.IndigoFramebufferServices FramebufferRendererHint 3

Trying to uninstall an app in Simulator using xcrun simctl uninstall will fail and hang. (30586964)


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Xcode 9 beta 2 Relea Workaround: Use xcrun simctl erase to completely reset the device to its initial state, or delete the app from the device’s home screen in Simulator.app

Interacting with the ringer switch in a simulated iOS device does not show a response in the UI. (32398343) Simulator devices will show as all black on some hardware. (32436030) Workaround: Try defaults write com.apple.CoreSimulator.IndigoFramebufferServices FramebufferRendererHint 1

to force use of Metal. If that doesn’t work, try 2 (force use of OpenCL). You can remove this workaround once the issue is fixed by running defaults delete com.apple.CoreSimulator.IndigoFramebufferServices

App installation can fail if a file in the app bundle is read-only. (32589563) Workaround: Use chmod u+w to add write permission to the file that is tripping up installation. Xcode 9’s Simulator.app may take 10 seconds to quit after launching Xcode 8. (32586683) Workaround: Quit Xcode 9 and all of its related apps before switching to Xcode 8. CoreNFC is not testable in Simulator. (32619896)


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Xcode 9 beta 2 Relea Resolved in Xcode 9 beta 2 — Apple LLVM and Swift Compilers Swift Compiler In Swift 4, closures that are invoked immediately are no longer type-checked as escaping closures. (SR–4735) (31910280)


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Xcode 9 beta 2 Relea Known Issues in Xcode 9 beta 2 — Apple LLVM and Swift Compilers Swift Compiler The Swift compiler diagnoses attempts to use NSCoding with a class that doesn’t have a simple Objective-C runtime name. The names of these classes are fragile and may be affected by unrelated changes. For example, the runtime name of a private class depends on the name of the containing source file.(32314195) Workaround: Use the @objc attribute to explicitly specify a runtime name instead. If you archive the class under its current “mangled” name, the compiler will provide a fix-it to use it. Attempting to use the Accelerate framework from Swift may generate linker errors about missing simd symbols such as: error: Couldn't lookup symbols: __T04simd6float4VN").

(32457742) Workaround: Manually add “import simd” to the Swift file. The Foundation protocol NSItemProviderReading introduces a new required initializer on NSString and other common Foundation types: required init(itemProviderData data: Data, typeIdentifier: String)

This new requirement on subclasses of these types in Swift is temporary and will be removed in a future seed. (32302018) The Swift compiler will crash in Swift 4.0 mode if a target’s bridging header contains an Objective-C class with generic parameters. This also applies to the debugger, which always runs in Swift 4.0 mode. (32463543) The Swift compiler will crash if a key path literal is written with a protocol type as its root type. (SR–4917) (32254554) Image literals result in an immediate run-time exit when used outside the main application target. (26873717) Workaround: Continue using NSImage or UIImage APIs to create images in non-application targets. When an NSDictionary is bridged into Swift as a Dictionary with AnyHashable keys, then using Swift integer values to index the dictionary may fail to find objects inside the dictionary.  Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea For example:

// Objective-C NSDictionary *makeDict() { return @{@(NSOrderedAscending): @"ascending"}; } // Swift let dict = makeDict() // Fails to find key in dictionary dict[NSComparisonResult.orderedAscending.rawValue]

(29026017) Workaround: Explicitly construct an NSNumber instance for the lookup key to the dictionary. // Swift dict[NSNumber(value: NSComparisonResult.orderedAscending.rawValue)]

The Swift compiler may crash during the “Merge MyApp.swiftmodule” build step.(30851899) Workaround: Disable the “Precompile Bridging Header” build setting for this target. Some exclusive access to memory enforcement conflicts may not be diagnosed when one of the accesses is performed in a non-escaping closure. (32020710) Dynamic checks for exclusivity enforcement are not enabled by default and are not ed in optimized builds. They can be enabled in unoptimized builds by changing the Build Setting “Exclusive Access to Memory” to “Full Enforcement.” (32273018) Constraining an associated type B to be a subtype of another associated type A (as in the code sample below) results in a compiler crash. In Swift 3.1 this code was accepted, but failed to constrain B in any way; however, the Swift 3.1 compiler would crash if a type conforming to the protocol used different types for A and B. protocol Base { associatedtype A: AnyObject } protocol Sub: Base { associatedtype B: A }

(SR–4981) (32409449) Workaround: Use the new feature explicitly requiring the two associated types to be the same (associatedtype B where B == A), or drop the requirement on B for compatibility with Swift 3.1.


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Xcode 9 beta 2 Relea Key path literals do not work when referring to computed properties of generic types. This includes generic properties declared by protocols and non-final class properties. (31768590) Non-object types marked with __attribute__((swift_wrapper(enum))), imported into Swift, then subsequently ed to an Objective-C or C function will be mangled. This also applies to NS_STRING_ENUM. For example, in a C header: typedef const char * MyEnumeration __attribute__((swift_wrapper(enum))); extern const MyEnumeration MyEnumerationValue1; extern const MyEnumeration MyEnumerationValue2; void myFunction(MyEnumeration input);

And then called from Swift: myFunction(.value1)

(32407790) Workaround: Avoid marking non-object types with this attribute. Typing a string interpolation segment such as “(foo)” outside of a string literal may cause the Swift compiler to crash. (32315365) Swift code that uses key paths may trigger “pointer not aligned at address” linker warnings. These are harmless and can be ignored. (32318829)


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Xcode 9 beta 2 Relea Swift Standard Library

for the PartialKeyPath type is not fully implemented. Attempting to look up a PartialKeyPath on a value of its root type, as in foo[keyPath: partialKeyPath], will give an incorrect “has no subscript ” error. (32237567) Sequences of labelled key/value pairs cannot be used with the Dictionary.merge method. The most prominent of these is Dictionary itself. (SR–4969) (32352586) Workaround: Map your labelled sequence to an unlabeled one: d1.merging(d2.lazy.map { ($0.key,$0.value) }) { $1 }

Not every method available on String is available on the Substring type such as precomposedStringWithCanonicalMapping. (32382183) Workaround: Wrap a String constructor around the Substring. For example: String(substr.precomposedStringWithCanonicalMapping)

In some cases there are extra String copies being made when using the Substring type which may slightly impact performance. (32469150)


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Xcode 9 beta 2 Relea New in Xcode Xcode 9 beta – IDE General Xcode 9.0 s running multiple concurrent versions of the Xcode app and of any associated tools such as Simulator. Xcode 9.0 can not be run at the same time as earlier versions. (23140937) -runFirstLaunch, a new flag in xcodebuild interactively checks the status of the license

agreement and install any packages required for launching Xcode. (23529342) A file with a base name of FooTest or FooTests is now considered a counterpart of a file with a base name of Foo for navigation and the Assistant Editor. (28981734)

Source Editor When text is selected, typing a opening delimiter adds a matching closing delimiter at the end of the selection. Auto-matched delimiters include " ", ( ), [ ], { }. (29164633) You can now increase and decrease the source editor font using Command-plus and Command-minus. (21423189) Added a picker to the Fonts & Colors pane in Preferences to modify the source editor line spacing. (30571596) You can now choose from 3 cursors to use in the source editor. (31813260)


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Xcode 9 beta 2 Relea Interface Builder

UIView layout margins now have an option in the Size inspector to enable leading and trailing

margins to respect RTL languages at runtime. (30086042) Interface Builder s the vertical baseline-to-baseline constraints added in iOS 11 that update spacing based on changes in the Dynamic Type size. (30086144) Interface Builder now renders navigation bars, tab bars, and toolbars on the canvas in the same way they appear at runtime. (30983209) To use the new usesAutomaticRowHeights property of NSTableView in Interface Builder, choose “Automatic (Auto Layout)” from the Size inspector and set the Row Height value. The value is used as part of the auto layout calculation. (29511510) Interface Builder now warns when a view’s constraints can cause localization problems, such as truncation and clipping. (32141216) Interface Builder no longer compiles for iOS 6. Documents with older deployment targets can still be read, and their frames can be transitioned to iOS 7 and later. (28726486) Interface Builder uses UIView.safeAreaLayoutGuide as a replacement for the deprecated Top and Bottom layout guides in UIViewController. To use the new safe area, select Safe Area Layout Guides in the File inspector for the view controller, and then add constraints between your content and the new safe area anchors. This prevents your content from being obscured by top and bottom bars, and by the overscan region on tvOS. Constraints to the safe area are converted to Top and Bottom when deploying to earlier versions of iOS. (29323293) Interface Builder s setting textContentType on classes conforming to the UITextInputTraits protocol. This improves the ability of AutoFill to populate with appropriate data, including name and on iOS 11. (25019432) When a constraint is selected, the inspector now allows choosing a different first or second item to anchor it to. Depending on the constraint type, siblings and containers are available. Constraint constants are automatically updated to preserve current positioning. (17535216)

Asset Catalog Asset catalogs now named colors, which can be referenced in Interface Builder documents. (28900538) Asset catalogs now high-efficiency image formats, including .avci, .heic, and .heif file extensions. (29959599)


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Xcode 9 beta 2 Relea Main Thread Checker

Main Thread Checker is a new runtime tool that finds calls to APIs in AppKit, UIKit, and WebKit that must be made from the main thread, but are made on other threads. These calls are reported as runtime issues. Main Thread Checker is automatically enabled during debugging and can be disabled in the Diagnostics tab of the Scheme editor. (29951764)

Undefined Behavior Sanitizer Undefined Behavior Sanitizer is a new runtime tool that finds several types of undefined behavior in C languages, including integer overflows, invalid casts, and alignment violations. It has low overhead and can be enabled in the Diagnostics tab of the Scheme editor. Undefined Behavior Sanitizer is compatible with all other sanitizers. (15425728) Undefined Behavior Sanitizer can optionally detect nullability annotation violations at runtime. Go to Build Settings then set “Enable Nullability Annotation Checks” to “Yes” in the Undefined Behavior Sanitizer section. (30619298)

Address Sanitizer Address Sanitizer has been extended to check for cases when the scope of a variable has ended, but the underlying memory is used. It also has a new optional check that detects cases where memory backing a local variable is used after the function has returned. This check, for the use of stack memory after return, can be enabled in the Diagnostics tab of the Scheme editor. (32308829) Address Sanitizer is now compatible with Malloc Scribble. (32359908)

Thread Sanitizer Thread Sanitizer has been extended to catch higher-level races on Objective-C and Swift collections, such as writing to a mutable array from different threads without using proper synchronization. (26798589) Thread Sanitizer has been extended to catch when multiple threads call mutating methods on the same struct without synchronization. It will also catch many cross-thread violations of Swift’s rule requiring exclusive access to memory. (30455576)


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Xcode 9 beta 2 Relea Debugging

iOS devices and Apple TV can now be debugged over the network. For more information, see the topics in Xcode Help > Run and debug > Network debugging. (10968305) Memory graph files exported by Xcode or generated by the leaks command line tool will now save allocation backtraces if malloc stack logging is enabled. This makes the backtraces available for all the tools that memgraph files (leaks, vmmap, Xcode). (25399716) The View Debugger now s visual debugging of SpriteKit and SceneKit scenes. SpriteKit nodes are shown in the view hierarchy. For SceneKit scenes, select the SCNScene in the debug navigator to open the snapshot in the SceneKit editor. Changes in the SceneKit editor when it is in runtime debugging mode can be saved and do not change your app. (29169315) Choosing an action in the breakpoint editor sets it as the default action. (14560556) Xcode shows a visual indicator in the icon for a breakpoint that has a condition, an ignore count, one or more actions, or automatic continue enabled. (9023163) Added Quick Look for variables of type PDFDocument. (30108359) Added variables Quick Look for CIContext on 10.13 and later. (30390167) Added Quick Look for variables of type CIRenderTask on macOS 10.13 and later. (30911954) Added Quick Look for variables of type NSImageRep. (13257754) Adds Quick Look for variables of type CALayer. (31161558) Enhanced Quick Look for variables of type CIImage on macOS 10.13 and later. (30390177) The View Debugger now includes view controllers in the heirarchy and includes debugging information in the inspector. (16261359)


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Xcode 9 beta 2 Relea Project Navigator

Groups in the Project Navigator are now more closely associated with directories in the file system: Dragging files between groups in the Project Navigator now moves the files in the filesystem, and updates any associated SCM working copies. Creating, renaming, and deleting groups now performs the corresponding changes in the connected directory in the filesystem, if one is defined. Removing a group’s connection to a directory in the filesystem can now be done in the file inspector by clicking on the clear (X) button. Changing an association to a file or group can be now be done quickly by dragging and dropping the file or folder onto the “Location” section of the file inspector. (28612132)


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Xcode 9 beta 2 Relea Source Control

Xcode 9 includes a brand new Source Control navigator where you can easily see the working copies for your project or workspace. Each working copy lists branches, tags and remotes, and you can quickly see the currently checked out branch and push/pull counts for those branches. The gear and contextual menus allow you to create branches and tags, configure remotes, and perform tasks like checking out a revision or branch and merging changes between branches. New history and review files editors are displayed when clicking on a branch or tag in the Source Control navigator. You’ll see a full history for your branch or tag, including avatars, author and commit information and each commit is annotated with the branches and tags that correspond to that commit. A new SCM inspector allows you to see more details on a commit and double clicking a commit reveals the Review Files Editor (which shows all the files that were modified as part of a commit and the changes that were made). (29054970) Xcode 9 integrates with GitHub. You can easily manage your from the Xcode preferences window, including for two-factor authentication, and configure an SSH key to be used when performing Source Control operations against GitHub. (28775680) Xcode 9 includes for one-click clone from GitHub.com in Xcode when viewing repositories in your Web Browser. (32294826) Xcode 9 will no longer show repositories that you have cloned source code from in the past in the Preferences/s window. Instead, you can manage your GitHub and GitHub Enterprise s. (30191709) Xcode 9 includes a brand new Clone… window that integrates directly with GitHub to show you favorite, private/personal and organizational repositories for all of your s. For each repository, you’ll see metadata and be able to view the project Ree, and clone with oneclick. (30960520) Xcode 9 will now automatically fetch from remote tracking branches and mark files that have been updated in the project navigator, and show push/pull counts in the Source Control navigator. (31839384) The Source Control pane in Preferences includes configuring Git and SVN ignore file lists, and for configuring your Git author information. (10544339)

Build System New Build System Xcode 9 includes a new build system written from scratch in Swift. It is designed for higher reliability, and it catches project configuration problems which the standard build system does not. The performance of the build system (not including compilers, linkers, and other build tools)


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Xcode 9 beta 2 Relea has been dramatically improved. This new build system is built on top of the Swift open source llbuild project. In Xcode 9.0, the new build system is disabled by default, but it can be enabled for a project or workspace in the settings accessed with the Workspace Settings… or Project Settings… menu item in the File menu. ing the -UseNewBuildSystem=YES flag to xcodebuild will also force it to use the new build system for a command-line build. The new build system will become the default build system in a future version of Xcode. (19209225) While the new build system is highly compatible with existing projects, some projects may require changes when adopting it. Expected changes are due to the following: The new build system is more strict about detecting and producing an error if a cycle is detected between elements in the build, as cycles can cause unnecessary rebuilds, degrading build performance. To resolve this issue, ensure that all files are produced earlier in the build than when they are used. For example, if a target both produces an output and depends on other targets which use that output, move the production of the output into its own target which can be run earlier in the build. It is an error for any individual file in the build to be produced by more than one build command. For example, you may not declare the same output file from two shell script phases in separate targets, if they are both built at once (since the build system has no way to decide which to use). To resolve this, factor out any such tasks into a single target that can be depended upon by anyone requiring it. If an output file which is generated by a shell script is used as an input elsewhere in the build (for example, to another shell script), then that output must be declared as an explicit output by the script which generates it; otherwise the build system may attempt to search for the file before it has been generated, causing the build to fail. The traditional header map which was generated when the “Always Search Paths” (ALWAYS_SEARCH__PATHS) setting was YES is not ed by the new build system. Instead, projects should set ALWAYS_SEARCH__PATHS to NO and should migrate to using modern header include syntax: Add any needed header files which are in the project repository to the Xcode project, to ensure they are available for use in #include (via the project wide header map). Use quote-style include ("foo.h") for project headers, and reserve angle-bracket include ( ) for system headers. The new build system will undefined_arch as the value for the ARCH environment variable when running shell script build phases. The value was previously not well defined. Any shell scripts which were depending on this value should instead be written to behave correctly for all defined architectures being built, available via the ARCHS environment variable.  Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea The new build system does not the standard “clean” behavior, instead ing “clean build folder”.

The module.modulemap file that Xcode generates for a target containing Swift and defining a module now includes requires objc so it can be used by languages other than Objective-C (such as C++). (28650820) Autocreated schemes are no longer saved to disk unless they’ve been edited. This helps prevent the accumulation of schemes for targets which are deleted, or are added to other schemes. (30266825) Xcode’s project modernization workflow will recommend enabling the build setting “Implicit Objective-C Literal Conversions” (CLANG_WARN_OBJC_LITERAL_CONVERSION) to warn about implicit conversions from Objective-C literals to values of incompatible type. (32150034) Xcode’s project modernization workflow will recommend enabling the build setting “Implicit Non-Literal Null Conversions” (CLANG_WARN_NON_LITERAL_NULL_CONVERSION) to warn about non-literal expressions that evaluate to zero being treated as a null pointer. (32169031) The new “Strip Swift Symbols” (STRIP_SWIFT_SYMBOLS) build setting, which is enabled by default, adjusts the level of symbol stripping so that when the linked product of the build is stripped, all Swift symbols are removed. This significantly reduces the size of Swift frameworks. If the lack of Swift symbols causes problems, such as when using dladdr(), this setting can be disabled. To view the exported symbols from file that has been stripped, use “xcrun dyldinfo export” instead of nm. (31306055) The build setting “Separate Strip” (SEPARATE_STRIP) is no longer displayed in the build settings editor, and it is no longer ed. Xcode always strips binaries in a separate task and no longer instructs the linker to perform the strip. (31584192) A new build setting for the swift compiler, “Precompile Bridging Header” (SWIFT_PRECOMPILE_BRIDGING_HEADER), has been added. This is enabled by default, and adds a new step in mixed-source builds called ‘PrecompileSwiftBridgingHeader’, that improves overall build time. If unexpected errors occur during this step, disabling the build setting will omit this step. (31851450) There is a new build setting “Swift 3 @objc Inference” [SWIFT_SWIFT3_OBJC_INFERENCE] which controls how the Swift compiler infers @objc for declarations. By default it will use the declared Swift version in the target to perform this inference, but this setting can be used to explicitly direct the Swift compiler to use either Swift 3 to Swift 4 inference rules. (32121595) When a project is opened, Xcode will detect if any build files in targets in the project represent file references which are not present in that project’s group tree. Any such references will be added to a file group named “Recovered References”, which will be created if necessary. These references should be manually reorganized in the project as appropriate. (22924751)


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Xcode 9 beta 2 Relea The name of the build Intermediates folder in a build location is now Intermediates., which prevents Spotlight from indexing the contents of this folder. This change improves Xcode build times. (29336306)

Localization Export and import of localizations via XLIFF now s stringsdict files, including for using the correct plural variants per language. (16785521) A template for stringsdict files is now included in Xcode. (15483459)

Core Data The data model editor presents a unified interface for Core Data’s new fetch indexes feature as well as its existing property index and entity compound index features. Older data models are translated into fetch index form for editing, and saved to the old file format when necessary. Compiling a data model with a Deployment Target lower than iOS 11, watchOS 4, macOS 10.13, or tvOS 11 continues to generate a compatible compiled form. (30843153) The data model editor s the new URI attribute type. (31205307) The data model editor s the new UUID attribute type. (31205342) An attribute in a data model can now be marked as preserved after deletion, to the Core Data persistent history tracking feature. (31204966) An entity can have its Core Spotlight display name expression specified directly in the data model. (31619747) When generating code for Swift 4, data model code generation has been updated to use Swift structs when possible. Code generation for Swift 3 is unchanged. (27512827)

g and Distribution The distribution workflow has been enhanced to manual g. Manual g allows you to specify the precise set of distribution g certificates and provisioning profiles that you want to use when distributing your app. xcodebuild -exportArchive also s manual g, with new additions to the ExportOptions plist format for specifying a gStyle, a gCertificate, and a provisioningProfiles dictionary. See xcodebuild -help for the full list of ed ExportOptions keys. When automatically g for distribution, Xcode will now create and use only Xcodemanaged distribution provisioning profiles. This behavior is functionally analogous to automatic g for development, and means that Xcode will no longer create or modify any of your manually created distribution provisioning profiles. Xcode-managed distribution provisioning profiles are ed for all distribution methods except for Developer ID distribution.  Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea xcodebuild -exportArchive now fully s automatic g, including creating and

updating g assets, if you the -allowProvisioningUpdates flag.

In addition, when Xcode detects that you must create a new distribution g certificate, it will now prompt you for permission to create one and provide you with a convenient means to export the g certificate for safekeeping or for sharing with other team . Revoking distribution g certificates is no longer ed within the distribution workflow. The distribution workflow also no longer requires you to specify a team if your app was signed when you built your archive. Finally, the distribution workflow now outputs several additional files alongside your exported app: a DistributionSummary plist, a Packaging log, and an ExportOptions plist. The DistributionSummary plist describes the content of your exported app, including information about its signature; whether it includes symbols and bitcode; and its embedded content. The Packaging log is akin to a build log, and contains all of the commands used to transform the archived application into a packaged app for distribution. The ExportOptions.plist encapsulates all of the choices you made throughout the distribution workflow. It can be ed to xcodebuild -exportArchive to automate distribution of your app for continuous integration. (29054761) xcodebuild can now communicate with the Apple developer website to create and update

provisioning profiles, g certificates, and app IDs for targets that use automatic g. To enable this behavior, first add your Apple ID in Xcode’s s preferences window, and then the -allowProvisioningUpdates flag to xcodebuild when building. (27572834) Xcode s a new build setting, CODE_SIGN_STYLE, which can be used to override a target’s g style to Automatic or Manual when using xcodebuild. (28077832) When exporting a Swift app for a platform that s App Thinning, the distribution workflow shows a new option “Strip Swift Symbols” that controls whether Swift symbols should be stripped out of the Swift standard libraries. This significantly reduces the size of the Swift libraries. If the lack of Swift symbols causes problems, such as when using dladdr(), this setting can be disabled. (31669406)

Testing Xcode Server and xcodebuild now running tests in parallel on multiple devices and simulators. Bots can be configured to enable or disable parallel testing on devices, and by default bots will prefer to test in parallel. The output produced by xcodebuild when testing in parallel has been updated (any automated tooling relying on this output may need to be updated). (14254639) When running tests, xcodebuild will no longer launch Simulator. (27385435)


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Xcode 9 beta 2 Relea XCTest includes a new teardown block API for cleaning up test state after your test completes. (28097197) XCTest includes a new API that can be used to wait on an XCUIElement existing before proceeding. (28483267) XCTest now includes for targeting multiple applications in a single UI test, including monitoring application state and making a backgrounded application the frontmost application. (28948745) XCTest types that are closely associated with a particular class such as XCUIElement.Type are available as nested types in Swift 4. (29000570) Schemes with Code Coverage enabled (in the Test action) will now always build with Code Coverage, including for the Run and Launch actions. This reduces the need to build multiple versions of the application. s who require code coverage to be off for their non-test actions can explicitly use a separate scheme with coverage disabled. (31848014) XCTest includes XCTActivity, a new API for grouping UI test activity together in test reports and logging. (30401267) XCTest includes XCTAttachment, a new API for bundling diagnostic test resources such as rich logging along with your test results. (30478677) XCTest now includes new scheme-level configuration options for disabling automatic screenshots, and new API for capturing screenshots of partial, individual or multiple displays. (21327915) UI testing now s targeting LSUIElements-based applications. (21344280) Xcode 9 includes significant improvements to UI testing around performance when targeting applications built and installed by Xcode. XCTest now includes firstMatch for restricting query execution in UI tests. (22980005, 29544176) Tests can now be configured to run tests in a specific language and region using a scheme setting in Xcode. (28897796) By default, xcodebuild tests on multiple destinations simultaneously. To disable this feature, provide the -disable-concurrent-testing command line argument. (31964004) When Code Coverage is enabled in the Test action of a scheme, Xcode will no longer place the build intermediates and products from the Test action into a separate build location, and will instead use the same location as the Run action. Enabling Code Coverage for the Test action now also enables it for the build performed by the Run action. This causes a build for the Run action to take approximately 3% longer, but allows the Test and Run actions to share build products and intermediates, reducing overall build times when alternating between these actions. (32079317)  Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea When viewing coverage results for a test action invocation in Xcode, you will now see a numerical value for the coverage percentage too. (21531774)

Crashes Organizer The Crashes Organizer will symbolicate unsymbolicated logs when selected using local .dSYMs indexed by Spotlight. (22550064)

Templates In Xcode 9, the template macro expansion subsystem has been reworked. Improvements include: A new standard macro named FILEHEADER has been added that is the content for the standard file header comment. Macros can now be defined in of other macros. For example the new FILEHEADER macro is defined in of macros like FILENAME and COPYRIGHT. COPYRIGHT, in turn is defined in of ORGANIZATIONNAME and YEAR. Macro expansions can apply modifiers. This was faked in the old implementation by setting special macros that were made by turning other macros into identifiers or xml-safe variants, but now these modifiers can be used with any macro. The syntax is ___MACRONAME:modifier___. Multiple modifiers can be chained like ___MACRONAME:modifier1,modifier2___

Custom macro definitions and overrides can now be supplied. For more information, choose Help > Xcode Help and see the topics in Appendixes > Text Macros. (5775785)


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Xcode 9 beta 2 Relea Server

Xcode Server now s automatic and manual provisioning configurations for your project. For schemes that contain targets that use the automatic g style, an agent or of the developer team can add your server to your team from the updated bot editor. If your scheme requires manually specified certificates or profiles, they can be easily shared with the server from the new g tab in the bot editor. (15437174) Xcode Server now s configuring additional arguments that will be ed to xcodebuild when integrations run. (23578597) Xcode Server now s sending an “all clear” email notification when all issues being tracked by a bot have been resolved. (26179348) Xcode Server no longer requires the macOS Server app. Configure your server and bots using the Server & Bots tab in Xcode’s Preferences. (28211693) For additional information, see Xcode Server and Continuous Integration Guide. Bots can now be configured to run tests in a specific language and region. (30382604) Bots now configuration of an Export Options Plist that will be used when exporting an installable product from an archive. (31895193)


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Xcode 9 beta 2 Relea Simulator

Simulator shows a device bezel with buttons that send send the appropriate event to the device. (14020158) Simulator now s face-up and face-down orientations on ed devices. (11393667) Simulator now sets a touch radius on simulated touch input. (22561885) Simulator.app now respects the system screenshot directory instead of always saving screenshots to the desktop. (26127809) Simulator.app can now attach to simulators started from the command line and detach from simulators without shutting them down. To detach when closing a device window or quitting the app, hold down Control. You will be asked whether to shutdown or detach. A checkbox is provided to make whichever behavior you choose the default. To change the default, repeat the same procedure. (31004084) Simulator now provides a Share Extension. Photos and videos are imported into the device photo library. Locations or pins from Maps.app set the device’s simulated location. App bundles are installed. URLs are opened in Safari. Choose “All Simulators” to install to multiple simulators simultaneously. (31150602) Simulator now s edge swipe gestures when the device bezel is visible. Begin your gesture just outside the screen region. (31558767) Simulator.app now s running multiple devices simultaneously. As a result the separate “Simulator (Watch).app” has been removed. (5687722) To simulate moving the Apple Watch digital crown when the bezel is shown, move the pointer over the crown and use the macOS vertical scroll gesture. (31990733)


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Xcode 9 beta 2 Relea Resolved in Xcode Xcode 9 beta – IDE General A bug where code completion would not work in a new source file, or in a source file which had been renamed or moved, has been fixed. (29615992)

Interface Builder Fixed an issue where Objective-C annotations like NS_REFINED_FOR_SWIFT caused IBInspectable to not be recognized on a property. (30509152) Interface Builder now shows correct bar heights (status bar, top bar, bottom bar) when picking landscape for a device in the device configuration bar. (6799670)

Debugging Fixed an issue causing Quick Look of Swift URL variables to fail. (26549268) Fixed an issue causing Quick Look of Swift Data variables to fail. (26549284) Fixed an issue causing Quick Look of Swift CGImage variables to fail. (29001240)

Testing Many common errors impacting the reliability and reproducibility of testing with Simulator devices have been addressed. (32018540) XCTest APIs using NSUInteger are imported into Swift 4 as Int rather than UInt, bringing it into alignment with other system frameworks. (29589664) XCTest will now always capture a screenshot at the time of a test assertion when running a UI test. (28853076)

Crashes Organizer A number of stability, reliability, presentation, performance, and correctness fixes have been made to the Crashes Organizer. (29500046)

Source Control Xcode will no longer produce or update unwanted .xcscmblueprint files for your project or working copy. (31137015) Xcode 9 will now correctly show files as renamed in the commit sheet. (32049321)  Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea Build System

The TEMP_FILES_DIR build setting is properly exported to shell script build phases. (6652373)

Localization Xcode now uses “\n” and “\t” instead of literal newlines and tabs to represent newline and tab characters in generated strings files. (22981479) Xcode localization import/export now handles strings files with line endings other than the standard linefeed character. (30552675) Xcode no longer produces an error when exporting for localization when a localized resource is a member of more than one target. Instead, Xcode assumes that the resource should just be exported once, and that any imported translations will be shared among targets it is a member of as well. (19059103) Xcode now s XLIFF export for source files that use encodings other than UTF–8. (18944510)

Server Copy/paste and cmd+F now works as expected from the logs tab of an integration report. (14140192) You can now copy and paste when working with the Xcode Server logs. (26605066) Xcode Server now s two-factor authentication when ing your server to your development team, and no longer requires use of an app-specific . (27002415) A frequent hang in Xcode when connecting to Xcode Server has been resolved. (30338854) When an upgrade integration runs after installing a new version of Xcode, Xcode Server will now correctly indicate any changes in SDK versions. (30983641)


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Xcode 9 beta 2 Relea New in Xcode Xcode 9 beta – Apple LLVM and Swift Compilers Apple LLVM Compiler Incremental Link-Time Optimization (LTO) is 1.5x faster with the default debug information level in large projects, and is 3x faster at incremental builds. (22867330) Warnings for incomplete umbrella headers in module maps now trigger even when the umbrella header is part of a submodule. (22623686) Redefinition errors caused by repeated includes of non-modular headers now show the include stack that lead to the repeated include. (24116019) The new compiler flag -Wunguarded-availability warns for unguarded uses of Objective-C APIs that were introduced in a system whose version is newer than the deployment target version. A new Objective-C expression @available has been introduced to perform system version checking at runtime. An if statement with an @available condition can be used to guard uses of newer APIs: if (@available(macOS 10.13, iOS 11, *)) { // The compiler will not warn es of APIs from macOS 10.13 // or iOS 11 here }

C or C++ code can use the new __builtin_available builtin whose semantics are equivalent to @available. The -Wunguarded-availability flag is off by default to prevent unexpected warnings in existing projects. Its less strict sibling -Wunguarded-availability-new is on by default, and warns about unguarded uses of APIs only when they were introduced in or after macOS 10.13, iOS 11, tvOS 11 or watchOS 4. (7184689) When using code-completion for setters of block properties that use a typedef instead of specifying the block type directly, the placeholder for the block parameter will expand to the correct block declaration. (21981862) Xcode provides code-completion results for missing C++11 constructs and keywords. The following constructs are included in the code-completion results: static_assert alignas

The following keywords / special identifiers are included in the code-completion results:  Copyright © 2017 Apple Inc. All rights reserved.

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Xcode 9 beta 2 Relea constexpr final

noexcept override thread_local

The __auto_type keyword is included in code-completion results for code that uses C or Objective-C. (29219185) Xcode provides code-completion results for from dependent classes. For example: template void appendIfTrue(std::vector &dest, const T &value) { dest. // Xcode will now show relevant completion results after '.' }

Note that code-completion results won’t be provided when the member expression includes a dependent base. For example: template void appendIfTrue(std::vector<std::vector > &dest, const T &value) { dest.at(0). // Xcode *will not* have the relevant completion results // for the of std::vector here }

(29818301) The compiler will warn about performSelector calls which have a selector which could refer to a method returning a structure, union, or vector type. (12056271) The compiler warning -Wstrict-prototypes can be used to report warnings about nonprototype functions, block declarations, and types in C and Objective-C. (15060615) The description for the “expected identifier” error includes the uses of C++ keywords in Objective-C++ code that would have been accepted in plain Objective-C code. An example of one such error is shown below: error: expected identifier; 'new' is a keyword in Objective-C++ @protocol new ^

(20626062) The command-line option -iframeworkwithsysroot has been added which allows one to specify a framework include path that will be prefixed with the system root path (-isysroot). (21316352)


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Xcode 9 beta 2 Relea The compiler will reject Objective-C methods with a vector parameter or return value when compiling code for the i386 target for releases prior to macOS 10.11 or iOS 9. (21662309)

The compiler includes the state of the #pragma pack directive when including a pre-compiled header. (21359084)

Swift Language Archival and serialization API is built in to Swift, with a focus on type-safe conversions from external formats directly into native Swift types, and interoperability with common formats like JSON and plist. The Encodable and Decodable protocols (along with Codable, which implies both), allow types to participate in encoding and decoding mechanisms. public struct Person : Codable { let name: String let email: String }

(SE–0166) Encoders and Decoders allow for type-safe conversion to and from the JSON and property list

formats. Combined with the default Codable implementation, many types can natively convert to and from these formats, with no additional encoding or decoding work. For example: import Foundation let johnny = Person(name: "Johnny Appleseed", email: " [email protected]") let encoder = JSONEncoder() let data = try encoder.encode(johnny) // => {"name": "Johnny Appleseed", // "email": " [email protected]"} let decoder = JSONDecoder() let person = try decoder.decode(Person.self, from: data) print(person.name) // => Johnny Appleseed

(SE–0167) Swift 4 brings for new type safe key path literals. They are formed via syntax that looks like this: \BaseType.propertyName. The backslash is very important as it disambiguates between executing a property, and simply referencing it. When the BaseType can be inferred it can be elided producing expressions that look like: \.propertyName. Key path expressions produce instances from the hierarchy of KeyPath types (where BaseType is the dynamic type of the base, and PropertyType the type of named property):


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Xcode 9 beta 2 Relea KeyPath – readonly key path WritableKeyPath – read/write key path that can mutate a value type directly (similar to

inout/mutating) ReferenceWritablePath – read/write key path that can mutate reference types These new KeyPaths exist alongside the existing string #keyPath expressions introduced last year. #keyPath remains available for use with legacy String-based API. (SE–0161) Xcode 9 s both Swift 3.2 and Swift 4.0, as controlled by the “Swift Language Version” build setting. These two language modes are implemented using the same compiler and standard library, which allows you to link together targets using Swift 3 with targets using Swift 4. This means that in most cases migration from Swift 3.2 to Swift 4 can be done on a targetby-target basis. While Swift 3.2 and Swift 4.0 are intended to be compatible, the differences in how they view Cocoa and Cocoa Touch APIs can lead to inconsistencies, which may limit how a library built with Swift 3.2 can be used by a client target built with Swift 4.0 (or vice versa). This most commonly occurs as being absent from a type; in certain situations the client may be forbidden from subclassing certain classes or adopting certain protocols. Neither Swift 3.2 nor Swift 4.0 linking with targets compiled with any earlier versions of Swift, including Swift 3.1 (shipped with Xcode 8.3). As usual, if the compiler or SourceKit crashes, please file a bug report with your project and sources attached. If you are mixing Swift 3 and Swift 4 in your project please mention that in the description of the issue. (31104045) A new Substring type has been introduced. In Swift 4, slicing a String returns a Substring. In Swift 3.2, slicing a String continues to return a String, but the Substring operation can still be called through type context i.e. myString[i….] as Substring. Substring presents an almost-identical API as that of String. A new protocol, StringProtocol, is available to write generic code that applies to either String or Substring.

(32260315) String now conforms to BidirectionalCollection and RangeReplaceableCollection.

(32360041) You can now write multi-line string literals. A """ followed by a new line starts the literal, and a """ on a new line ends it. Every line after the initial quote must start with the same whitespace as the closing quote, which will be stripped out on compilation. (SE–0168) A dictionary can be created from a sequence of keys and values, and can merge keys and values into an existing dictionary. For example:


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Xcode 9 beta 2 Relea let asciiTable = Dictionary(uniqueKeysWithValues: zip("abcdefghijklmnopqrstuvwxyz", 97…)) // ["w": 119, "n": 110, "u": 117, "v": 118, "x": 120, "q": 113, …] let vegetables = ["tomato", "carrot", "onion", "onion", "carrot", "onion"] var vegetableCounts = Dictionary(zip(vegetables, repeatElement(1, count: Int.max)), uniquingKeysWith: +) vegetableCounts.merge([("tomato", 1)], uniquingKeysWith: +) // ["tomato": 2, "carrot": 2, "onion": 3]

(SE–0165) Filtering a set of a dictionary produces a result with the same type as the receiver. To transform the values of a dictionary, keeping the same keys, use the mapValues(_:) method. For example: let vowels: Set = ["a", "e", "i", "o", "u"] let asciiVowels = asciiTable.filter({ vowels.contains($0.key) }) asciiVowels["a"] // 97 asciiVowels["b"] // nil let asciiHexTable = asciiTable.mapValues({ "0x" + String($0, radix: 16) }) // ["w": "0x77", "n": "0x6e", "u": "0x75", "v": "0x76", // "x": "0x78", …]

(SE–0165) When using a key as a dictionary subscript, a default value to be returned can be supplied if the key is not present in the dictionary. For example: for veg in ["tomato", "cauliflower"] { vegetableCounts[veg, default: 0] += 1 } // ["tomato": 3, "carrot": 2, "onion": 3, "cauliflower": 1]

(SE–0165) Use the init(grouping:by:) initializer to convert an array or other sequence into a dictionary, grouped by a particular trait. let buttons = // an array of button instances let buttonsByStatus = Dictionary(grouping: buttons, by: { $0.isEnabled }) // How many enabled buttons? print("Enabled:", buttonsByStatus[true]?.count ?? 0)


Page 50 of 61

Xcode 9 beta 2 Relea (SE–0165)

Dictionaries and Sets have a visible capacity property and a reserveCapacity(_:) method similar to Array, and a Dictionary’s keys and values properties are represented by specialized collections. (SE–0165) It is now an error to perform a second access to a variable while it is being modified. Such accesses lead to code that is harder both for programmers and the compiler to understand. For example, the following code attempts to read from the variable array while the sort method is mutating it. This is now illegal: var array: [Int] = … array.sort { $0 < array[0] }

This rule is enforced by a combination of compile-time and run-time checks. Static checks are used for most local variables, constants, and parameters. In Swift 4 mode, static failures are errors and will block code from successfully compiling. In general, developers will need to rearrange their code (for example, by adding a local copy) to prevent these conflicting accesses. In Swift 3 mode, static failures are merely a warning, but this will be strengthened to an error in a future release of Swift, so developers should take action to fix any of these warnings they find. Dynamic checks are used for global variables, static type properties, class instance properties, and local variables that have been captured in an @escaping closure. In Swift 4 mode, failing a dynamic check will cause a trap, much like integer overflow does. In Swift 3 mode, failing a dynamic check merely causes a warning to be printed to stderr. The compile-time and run-time checks enforce the rule for accesses that occur within the same thread. Thread Sanitizer will be able to catch most (but not all) violations that occur from different threads. The common idiom of exchanging two elements of a collection using swap violates this rule. To this pattern, there is now a swapAt method on all mutable collections. (SE–0176) In Swift 4.0, extensions to the same type that are in the same file share an access control scope. If the type that they extend is also in the same file, they share its access control scope. This means that private declared in the type’s declaration can be accessed from extensions, and private declared in one extension can be accessed from other extensions and from the type’s declaration. (SE–0169) More generic algorithms are made possible by a new family of integer protocols: Numeric, containing arithmetic operators BinaryInteger, representing any number-like things FixedWidthInteger, the most concrete of them all, adding the concept of overflow to


Page 51 of 61

Xcode 9 beta 2 Relea arithmetic operations

Heterogeneous comparisons are now allowed, eliminating the need for numericCast in comparisons. For example, (42 as UInt) > (0 as Int) just works. With the introduction of smart shifts, it is possible to shift a value by a negative amount, numericCasts are also not necessary. The result type is the type of the shifted value. toIntMax() and init(_:IntMax) have been deprecated – numericCast converts directly

between different integer types without going through the maximum width integer. (SE–0104) Subscript declarations can now be defined to have generic parameter lists. Example: extension MyContainer { subscript (key: T) { … } }

(SE–0148) SQLite APIs can now be imported into Swift under the module name SQLite3. (18640410) Sequence has an associated type Element that is equivalent to Iterator.Element. The value

of this associated type can be inferred from existing Sequence conformance. Code that already declares a type of Element may need to be altered to resolve conflicts. (32186094) Slicing a raw buffer no longer results in the same raw buffer type. Specifically, Unsafe[Mutable]BufferPointer.SubSequence now has type [Mutable]RandomAccessSlice . Therefore, indexing into a raw buffer slice is no longer zero-based. This is required for raw buffers to fully conform to generic Collection. Changing the slice type resulted in the following behavioral changes: ing a region within a buffer to another function that takes a buffer can no longer be done via subscript: Incorrect: takesRawBuffer(buffer[i..<j]) This now requires explicit initialization, using a rebasing: initializer, which converts from a slice to a zero-based Unsafe[Mutable]RawBufferPointer: Correct: takesRawBuffer(UnsafeRawBufferPointer(rebasing: buffer[i..<j])) Subscript assignment directly from a buffer no longer compiles: Incorrect: buffer[n..<m] = smaller_buffer This now requires creation of a slice from the complete source buffer: Correct: buffer[n..<m] = smaller_buffer.suffix(from: 0)  Copyright © 2017 Apple Inc. All rights reserved.

Page 52 of 61

Xcode 9 beta 2 Relea UnsafeRawBufferPointer’s slice type no longer has a nonmutating subscript setter. So

asg into a mutable let buffer no longer compiles: Incorrect: let slice = buffer[n..<m] slice[i..<j] = buffer[k..

The assigned buffer slice now needs to be a var. Correct: var slice = buffer[n..<m] slice[i..<j] = buffer[k..

(SE–0138 Addendum) All Core Foundation types implicitly conform to the Equatable and Hashable protocols. This change applies in both Swift 3.2 and Swift 4.0. If you were previously adding these conformances in an extension, conditionalize the extension by using the following pattern: #if swift(>=3.2) // Equatable and Hashable are provided by Swift. #else extension TheCFTypeICareAbout: Hashable { static func ==(left: TheCFTypeICareAbout, right: TheCFTypeICareAbout) -> Bool { return CFEqual(left, right) } var hashValue: Int { return CFHash(self) } } #endif

(SR–2388) In Swift 4.0, if an Objective-C class has a designated initializer that can’t be imported into Swift, any Swift subclasses of that class will not inherit any convenience initializers. (31563662) A new protocol RangeExpression is now used to unify all range types (such as CountableRange, ClosedRange), and new one-sided ranges (such as PartialRangeUpTo) have been added. Any type that conforms to RangeExpression can now be used to slice a collection. For example:


Page 53 of 61

Xcode 9 beta 2 Relea let numbers = [10, 20, 30, 40, 50, 60] if let i = numbers.index(of: 40) { print(numbers[..
Countable partial ranges can be used as sequences. For example: let alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" let asciiTable = zip(65…, alphabet) for (code, letter) in asciiTable { print(code, letter) } // "65 A" // "66 B" // "67 C" // … // "89 Y" // "90 Z"

(32260581) Protocol composition types can now contain one or more class type , forming a classconstrained protocol composition. For example: protocol Paintable { func paint() } class Canvas { var origin: CGPoint } class Wall : Canvas, Paintable { func paint() { … } } func render(_: Canvas & Paintable) { … } render(Wall())

Note that class-constrained protocol compositions can be written and used in both Swift 3 and Swift 4 mode. Generated headers for Swift APIs will map class-constrained protocol compositions to Objective-C protocol-qualified class types in both Swift 3 and Swift 4 mode (for instance,


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Xcode 9 beta 2 Relea NSSomeClass & SomeProto & OtherProto in Swift becomes NSSomeClass <SomeProto, OtherProto> in Objective-C).

Objective-C APIs which use protocol-qualified class types differ in behavior when imported by a module compiled in Swift 3 mode and Swift 4 mode. In Swift 3 mode, these APIs will continue to import as protocol compositions without a class constraint (eg, SomeProto & OtherProto). In Swift 4 mode, protocol-qualified class types import as class-constrained protocol compositions, for a more faithful mapping of APIs from Objective-C to Swift. Note that the current implementation of class-constrained protocol compositions lacks three features outlined in the Swift evolution proposal: In the evolution proposal, a class-constrained protocol composition is permitted to contain two different classes as long as one is a superclass of the other. The current implementation only allows multiple classes to appear in the composition if they are identical. In the evolution proposal, associated type and class inheritance clauses are generalized to allow class-constrained protocol compositions. The current implementation does not allow this. In the evolution proposal, protocol inheritance clauses are allowed to contain a class, placing a requirement that all conforming types are a subclass of the given class. The current implementation does not allow this. These missing aspects of the proposal can be introduced in a future release without breaking source compatibility with existing code. (SE–0156) NSNumber is more strict about the result of bridging some of its values to corresponding Swift value types. Specifically, using an as? cast will return nil if the value stored by NSNumber does not fit into the requested Swift value type. For example, NSNumber(2) as? Bool will return nil, but NSNumber(1) as? Bool will return true. If you wish to force a cast and ignore this behavior, use the appropriate conversion function on NSNumber instead. For example, myNumber.boolValue. (SE–0170)

Swift Compiler Protocols and associated types can now contain where clauses that provide additional restrictions on associated types. For example:


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Xcode 9 beta 2 Relea protocol StringRepresentable: RawRepresentable where RawValue == String { } protocol RawStringWrapper { associatedtype Wrapped: RawRepresentable where Wrapper.RawValue == String }

(SE–0142) The Swift compiler now lazily and implicitly imports outer modules when importing a submodule after Swift finishes parsing the bridging header. This is a behavior change from previous releases where the import happened eagerly. As a result, some bridging headers that might have relied on the eager implicit import (such as by directly using a type defined in the outer module) will no longer compile; they will need to either forward-declare such definitions or explicitly import the outer module. (30615193) In order for default argument expressions to be inlined into the caller in a future version of Swift, they must not reference any declarations that have less access than the enclosing function. For example: // Before private func computeTheBestInteger() -> Int { return 4 } public func useAnInteger(_ x: Int = computeTheBestInteger().absoluteValue) { print(x) }

There are multiple ways to modify existing code to satisfy this condition: Option 1: Change the non-public reference to be public. public func computeTheBestInteger() -> Int { return 4 } public func useAnInteger(_ x: Int = computeTheBestInteger().absoluteValue) { print(x) }

Option 2: Add a helper function.


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Xcode 9 beta 2 Relea private func computeTheBestInteger() -> Int { return 4 } public func defaultXForUseAnInteger() -> Int { return computeTheBestInteger().absoluteValue } public func useAnInteger(_ x: Int = defaultXForUseAnInteger()) { print(x) }

Option 3: Use a sentinel. private func computeTheBestInteger() -> Int { return 4 } public func useAnInteger(_ xOrNil: Int? = nil) { let x = xOrNil ?? (computeTheBestInteger().absoluteValue) print(x) }

(32189807) In Swift 4 mode, a declaration is inferred to be @objc where it is required for semantic consistency of the programming model. Specifically, it is inferred when: The declaration is an override of an @objc declaration The declaration satisfies a requirement in an @objc protocol The declaration has one of the following attributes: @IBAction, @IBOutlet, @IBInspectable, @GKInspectable, or @NSManaged Additionally, in Swift 4 mode, dynamic declarations that don’t have @objc inferred based on the rules above will need to be explicitly marked @objc. Swift 3.2 retains the more-permissive Swift 3 rules for inference of @objc within subclasses of NSObject. However, the compiler will emit warnings about places where the Objective-C entry points for these inference cases are used, such as in a #selector or #keyPath expression, via messaging through AnyObject, or direct uses in Objective-C code within a mixed Swift and Objective-C project. The warnings can be silenced by adding an explicit @objc. Uses of these entry points that are not statically visible to the compiler can be diagnosed at runtime by setting the environment variable SWIFT_DEBUG_IMPLICIT_OBJC_ENTRYPOINT to a value between 1 and 3 then testing the application. (SE–0160) In Swift 4 mode, Swift’s type system properly distinguishes between functions that take one tuple argument, and functions that take multiple arguments. (SE–0110)

Swift Package Manager


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Xcode 9 beta 2 Relea A package can declare the minimum version of the Swift tools (including the Swift package manager) that are needed in order to use the package. (SE–0152)

The package manifest API has been improved as documented in SE–0158: Package Manager Manifest API Redesign. Packages using the old API can still be parsed, but by using the new “minimum tools version” functionality described above, new versions of package manifests can opt into the new API. (SR–3949) A package can choose whether the Swift source files in it should be compiled using Swift 3 or Swift 4 syntax. (SE–0151) A package can explicitly declare the products that the package vends to its clients (previously, they were inferred based on the targets in the package) as described in SE–0146: Package Manager Product Definitions. (SR–3606) Custom directory layouts are ed for the source files in a package. Specifically, each target in a package can specify the path of the directory that contains the source files for that target. (SE–0162, SR–29) In order to custom directory layouts, the location of the LinuxMain.swift file that lists the unit test targets for use on Linux is more flexible. Specifically, the Swift Package Manager will look for LinuxMain.swift in any directory that contains a test target directory, and in any ancestor thereof (up to the package root directory). (31585721) Package dependencies can now refer to a branch name instead of a tagged version. This is only intended for dependencies on packages that are closely coupled with all of their clients. Tagged versions of a package must not depend on any branches. (SE–0150, SR–666) The package edit command has a --path option that lets s manage their own checkout of the remote package, ing “top-of-tree” development of a related set of packages. (SE–0149, SR–3709) The pinning feature has been removed. In its place, packages now produce a Package.resolved file containing resolved dependency versions, which can optionally be committed to Git to share those versions. When present, dependency resolution will prefer the recorded dependency versions. The swift package fetch command has been replaced with a swift package resolve command. Related dependency resolution behaviors have been improved. (SE–0175) On macOS, package manifest interpretation and package builds now occur in a sandbox which prevents network access and file system modification. This helps mitigate the effect of maliciously crafted manifests. (31107213) The swift package edit command resolves package dependencies before putting the package into edit mode, so that any dependency resolution errors are detected before changes are made. (29772779)  Copyright © 2017 Apple Inc. All rights reserved.

Page 58 of 61

Xcode 9 beta 2 Relea The --branch option of the swift package edit command is optional. If no branch is provided, the Git repository is put into “detached head” state. (30120243)

The package manager emits clearer and more informative error messages for many problems. (29772725) On macOS, building a package only requires the Xcode Command Line Tools, not the full Xcode IDE, to be installed. Running unit tests still requires the Xcode IDE to be installed. (30813768) The error message that is shown when package dependencies cannot be satisfied now explains which dependency requirements are in conflict. (SR–4072, SR–4237) Generated Xcode projects use stable and readable object identifiers for objects such as targets, allowing Xcode schemes to continue referencing the same objects even when the project is regenerated with modified contents. (31019219) Cloned package dependencies will have read-only file permissions, reducing the risk of unintentional changes. When a package is put into edit mode, write permission is added for the files in that package. (31286403) C targets are now linked statically by default. This can be controlled using the type argument to a .library() initializer in the new product API. (29730882)


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Xcode 9 beta 2 Relea Resolved in Xcode Xcode 9 beta – Apple LLVM and Swift Compilers Apple LLVM Compiler The -Wdocumentation warning allows the use of \param and \returns documentation directives in the documentation comment for a declaration with a function or a block pointer type. (24978538) The compiler does not warn about unreachable __builtin_unreachable() statements. (28397146) The compiler is aware of editor placeholders that are inserted by Xcode when inserting a codecompletion result. It can provide better diagnostics and recover better when parsing files with editor placeholders. Several errors that were caused by editor placeholders are now suppressed in live-issues in Xcode. (31581400) The compiler will not crash when building with clang modules and using different -Werror flags for different source files. (32338950) The compiler will not crash when building with clang modules and using a precompiled header. (32359950)


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Xcode 9 beta 2 Relea Swift Compiler

A crash in the Swift compiler when an Objective-C property is redeclared with a different type or nullability has been resolved. This may lead to certain Objective-C being imported differently than before, including some properties being imported as read-only (if the setter is not consistent with the original property), and others no longer being imported as methods. (30785976) Covariant method overrides in classes are now fully ed, fixing many crashes and compile-time assertions when defining or calling such methods. For example: class Bed {} class Nook : Bed {} class Cat { func eat(snack: T) {} func play(game: String) {} func sleep(where: Nook) {} } class Dog : Cat<(Int, Int)> { // 'T' becomes concrete override func eat(snack: (Int, Int)) {} // 'game' becomes optional override func play(game: String?) {} // 'where' becomes a superclass override func sleep(where: Bed) {} }

SR–1529

Swift Package Manager The package manager properly errors if there is a parsing issue in the manifest of an edited package. (31085712)


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