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Compiling the engine on Xcode 26 for iOS fails with fatal error: 'UIUtilities/UIDefines.h' file not found #171755

@danagbemava-nc

Description

@danagbemava-nc

Steps to reproduce

Note

Prerequisite: Xcode 26 beta (either 1 or 2)

  • Clone the flutter Repo
  • Add the .gclient file and sync
  • In the engine src directory run ./flutter/tools/gn --ios --unoptimized
  • Run ninja -C out/ios_debug_unopt

Expected results

The engine compiles successfully

Actual results

The engine fails to compile for iOS with fatal error: 'UIUtilities/UIDefines.h' file not found. More details in the logs section below. This happens with the arm64 version as well (i.e ninja -C out/ios_debug_unopt_arm64)

This works as expected with Xcode 16.4 but not Xcode 26 beta 1 or beta 2.

Code sample

N/A

Screenshots or Video

N/A

Logs

Logs
ninja -C out/ios_debug_unopt          
ninja: Entering directory `out/ios_debug_unopt'
[3147/6993] OBJC obj/flutter/shell/platform/darwin/ios/framework/Source/libcopy_and_verify_framework_module.FlutterUmbrellaImport.o
FAILED: obj/flutter/shell/platform/darwin/ios/framework/Source/libcopy_and_verify_framework_module.FlutterUmbrellaImport.o 
../../flutter/buildtools/mac-arm64/clang/bin/clang++ -MMD -MF obj/flutter/shell/platform/darwin/ios/framework/Source/libcopy_and_verify_framework_module.FlutterUmbrellaImport.o.d -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D_FORTIFY_SOURCE=2 -D_LIBCPP_DISABLE_AVAILABILITY=1 -D_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS -D_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS -D_DEBUG -I../.. -Igen -I../../flutter/third_party/libcxxabi/include -I../../flutter/build/secondary/flutter/third_party/libcxx/config -fno-strict-aliasing --target=arm64-apple-darwin -arch arm64 -fcolor-diagnostics -Wall -Wextra -Wendif-labels -Wno-missing-field-initializers -Wno-unused-parameter -Werror -Wno-unused-but-set-parameter -Wno-unused-but-set-variable -Wno-psabi -Wno-implicit-int-float-conversion -Wno-deprecated-copy -Wno-deprecated-literal-operator -Wno-unqualified-std-cast-call -Wno-non-c-typedef-for-linkage -Wno-range-loop-construct -Wunguarded-availability -Wno-deprecated-declarations -fdebug-prefix-map=/Users/nexus/dev/sdks/exem/flutter/engine/src/= -no-canonical-prefixes -fvisibility=hidden -Wstring-conversion -Wnewline-eof -O0 -g2  -F/Users/nexus/dev/sdks/exem/flutter/engine/src/out/ios_debug_unopt -fapplication-extension -isysroot ../../flutter/prebuilts/SDKs/iPhoneOS26.0.sdk -miphoneos-version-min=13.0  -c ../../flutter/shell/platform/darwin/ios/framework/Source/FlutterUmbrellaImport.m -o obj/flutter/shell/platform/darwin/ios/framework/Source/libcopy_and_verify_framework_module.FlutterUmbrellaImport.o
In file included from ../../flutter/shell/platform/darwin/ios/framework/Source/FlutterUmbrellaImport.m:11:
In file included from /Users/nexus/dev/sdks/exem/flutter/engine/src/out/ios_debug_unopt/Flutter.framework/Headers/Flutter.h:8:
In file included from /Users/nexus/dev/sdks/exem/flutter/engine/src/out/ios_debug_unopt/Flutter.framework/Headers/FlutterAppDelegate.h:8:
In file included from ../../flutter/prebuilts/SDKs/iPhoneOS26.0.sdk/System/Library/Frameworks/UIKit.framework/Headers/UIKit.h:9:
In file included from ../../flutter/prebuilts/SDKs/iPhoneOS26.0.sdk/System/Library/Frameworks/UIKit.framework/Headers/UIKitCore.h:9:
../../flutter/prebuilts/SDKs/iPhoneOS26.0.sdk/System/Library/Frameworks/UIKit.framework/Headers/UIKitDefines.h:10:9: fatal error: 'UIUtilities/UIDefines.h' file not found
   10 | #import <UIUtilities/UIDefines.h>
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
[3156/6993] ACTION //flutter/lib/snapshot:strong_platform(//build/toolchain/mac:ios_clang_arm)
ninja: build stopped: subcommand failed.

Flutter Doctor output

Doctor output
[!] Flutter (Channel master, 3.33.0-1.0.pre.850, on macOS 15.5 24F74 darwin-arm64, locale en-GH) [3.0s]
    • Flutter version 3.33.0-1.0.pre.850 on channel master at /Users/nexus/dev/sdks/exem/flutter
    ! Warning: `flutter` on your path resolves to /Users/nexus/dev/sdks/flutter/bin/flutter, which is not inside your current Flutter SDK checkout
      at /Users/nexus/dev/sdks/exem/flutter. Consider adding /Users/nexus/dev/sdks/exem/flutter/bin to the front of your path.
    ! Warning: `dart` on your path resolves to /Users/nexus/dev/sdks/flutter/bin/dart, which is not inside your current Flutter SDK checkout at
      /Users/nexus/dev/sdks/exem/flutter. Consider adding /Users/nexus/dev/sdks/exem/flutter/bin to the front of your path.
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 6bd4019f74 (3 hours ago), 2025-07-08 01:10:26 -0400
    • Engine revision 6bd4019f74
    • Dart version 3.9.0 (build 3.9.0-293.0.dev)
    • DevTools version 2.48.0-dev.0
    • Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations,
      enable-native-assets
    • If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and
      upgrades.

[✓] Android toolchain - develop for Android devices (Android SDK version 36.0.0) [3.5s]
    • Android SDK at /Users/nexus/Library/Android/sdk
    • Emulator version 35.5.10.0 (build_id 13402964) (CL:N/A)
    • Platform android-36, build-tools 36.0.0
    • ANDROID_HOME = /Users/nexus/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
      This is the JDK bundled with the latest Android Studio installation on this machine.
      To manually set the JDK path, use: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13368085-b895.109)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 26.0) [1,527ms]
    • Xcode at /Applications/Xcode-26.0.0-Beta.app/Contents/Developer
    • Build 17A5241e
    • CocoaPods version 1.16.2

[✓] Chrome - develop for the web [83ms]
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2024.3) [82ms]
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13368085-b895.109)

[✓] Android Studio (version 2023.3) [79ms]
    • Android Studio at /Users/nexus/Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 17.0.10+0-17.0.10b1087.21-11572160)

[✓] Android Studio (version 2024.3) [79ms]
    • Android Studio at /Users/nexus/Applications/Android Studio Meerkat Feature Drop 2024.3.2 Patch 1.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 21.0.6+-13368085-b895.109)

[✓] IntelliJ IDEA Ultimate Edition (version 2025.1.2) [79ms]
    • IntelliJ at /Applications/IntelliJ IDEA Ultimate.app
    • Flutter plugin version 86.0.2
    • Dart plugin version 251.25410.28

[✓] VS Code (version 1.101.2) [3ms]
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.112.0

[✓] Connected device (5 available) [7.4s]
    • sdk gphone64 arm64 (mobile) • emulator-5554             • android-arm64  • Android 16 (API 36) (emulator)
    • sdk gphone64 arm64 (mobile) • emulator-5556             • android-arm64  • Android 16 (API 36) (emulator)
    • Nexus (wireless) (mobile)   • 00008020-001875E83A38002E • ios            • iOS 18.5 22F76
    • macOS (desktop)             • macos                     • darwin-arm64   • macOS 15.5 24F74 darwin-arm64
    • Chrome (web)                • chrome                    • web-javascript • Google Chrome 138.0.7204.93

[✓] Network resources [1,119ms]
    • All expected network resources are available.

! Doctor found issues in 1 category.

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P1High-priority issues at the top of the work listengineflutter/engine related. See also e: labels.from: manual-qaIssue caught from manual QA processhas reproducible stepsThe issue has been confirmed reproducible and is ready to work onplatform-iosiOS applications specificallyr: solvedIssue is closed as solvedteam-iosOwned by iOS platform teamtriaged-iosTriaged by iOS platform team

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