Update toolchains for Xcode 26.3 and Swift 6.2.4

.github/actions/build-xcframework/action.yml

@@ -5,7 +5,7 @@ inputs:
   xcode-version:
     description: 'Xcode version to use'
     required: false
-    default: '16.4'
+    default: '26.3'
   tag-name:
     description: 'Tag name for release URLs (empty for manual builds)'
     required: false

.github/actions/uitests/action.yml

@@ -5,7 +5,7 @@ inputs:
   xcode-version:
     description: 'Xcode version to use'
     required: false
-    default: '16.4'
+    default: '26.3'
   platform:
     description: 'Platform to test (ios or macos)'
     required: true

.github/workflows/compatibility_tests.yml

@@ -13,7 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-15]
-        xcode-version: ["16.4"]
+        xcode-version: ["26.3"]
         release: [2024]
     # Limit to self-hosted to reduce action cost
     runs-on:
@@ -42,7 +42,9 @@ jobs:
       - name: Run compatibility tests on OpenSwiftUI + macOS
         run: |
           set -o pipefail
+          # Swift 6.2 can duplicate-link swift-syntax macro prebuilts; Swift 6.3 fixes this.
           NSUnbufferedIO=YES swift test \
+            --disable-experimental-prebuilts \
             --filter OpenSwiftUICompatibilityTests \
             --build-path .build-compatibility-test-debug \
             2>&1 | xcbeautify --renderer github-actions --preserve-unbeautified
@@ -51,7 +53,9 @@ jobs:
       - name: Run compatibility tests on SwiftUI + macOS
         run: |
           set -o pipefail
+          # Swift 6.2 can duplicate-link swift-syntax macro prebuilts; Swift 6.3 fixes this.
           NSUnbufferedIO=YES swift test \
+            --disable-experimental-prebuilts \
             --filter OpenSwiftUICompatibilityTests \
             --build-path .build-compatibility-test-debug \
             2>&1 | xcbeautify --renderer github-actions --preserve-unbeautified
@@ -63,7 +67,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-15]
-        xcode-version: ["16.4"]
+        xcode-version: ["26.3"]
         release: [2024]
         ios-version: ["18.5"]
         include:
@@ -97,26 +101,35 @@ jobs:
       - name: Run compatibility tests on OpenSwiftUI + iOS
         run: |
           set -o pipefail
-          NSUnbufferedIO=YES xcodebuild test \
+          # Swift 6.2 can duplicate-link swift-syntax macro prebuilts; Swift 6.3 fixes this.
+          # Xcode 26.3 + iOS 18.5 fails to launch arm64 SwiftPM package test
+          # runners with CoreSimulator codesigning errors; force the x86_64
+          # simulator slice until that launch path is fixed.
+          NSUnbufferedIO=YES xcodebuild -IDEPackageEnablePrebuilts=NO test \
             -scheme OpenSwiftUI \
             -configuration Debug \
-            -destination "platform=iOS Simulator,OS=${{ matrix.ios-version }},name=${{ matrix.ios-simulator-name }}" \
+            -destination "platform=iOS Simulator,OS=${{ matrix.ios-version }},name=${{ matrix.ios-simulator-name }},arch=x86_64" \
             -only-testing:OpenSwiftUICompatibilityTests \
             -skipMacroValidation \
             -skipPackagePluginValidation \
+            ONLY_ACTIVE_ARCH=YES \
             2>&1 | xcbeautify --renderer github-actions --preserve-unbeautified
         env:
           OPENSWIFTUI_COMPATIBILITY_TEST: 0
       - name: Run compatibility tests on SwiftUI + iOS
         run: |
           set -o pipefail
-          NSUnbufferedIO=YES xcodebuild test \
+          # Swift 6.2 can duplicate-link swift-syntax macro prebuilts; Swift 6.3 fixes this.
+          # See the OpenSwiftUI iOS compatibility step above: force x86_64 to
+          # avoid the arm64 package test runner launch/codesigning failure.
+          NSUnbufferedIO=YES xcodebuild -IDEPackageEnablePrebuilts=NO test \
             -scheme OpenSwiftUI \
             -configuration Debug \
-            -destination "platform=iOS Simulator,OS=${{ matrix.ios-version }},name=${{ matrix.ios-simulator-name }}" \
+            -destination "platform=iOS Simulator,OS=${{ matrix.ios-version }},name=${{ matrix.ios-simulator-name }},arch=x86_64" \
             -only-testing:OpenSwiftUICompatibilityTests \
             -skipMacroValidation \
             -skipPackagePluginValidation \
+            ONLY_ACTIVE_ARCH=YES \
             2>&1 | xcbeautify --renderer github-actions --preserve-unbeautified
         env:
-          OPENSWIFTUI_COMPATIBILITY_TEST: 1
+          OPENSWIFTUI_COMPATIBILITY_TEST: 1

.github/workflows/ios.yml

@@ -13,7 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-15]
-        xcode-version: ["16.4"]
+        xcode-version: ["26.3"]
         release: [2024]
         ios-version: ["18.5"]
         include:
@@ -48,20 +48,27 @@ jobs:
       - name: Build test target in debug mode
         run: |
           set -o pipefail
+          # Xcode 26.3 + iOS 18.5 fails to launch arm64 SwiftPM package test
+          # runners with CoreSimulator codesigning errors. Build the x86_64
+          # simulator slice to match the test command below until that is fixed.
           NSUnbufferedIO=YES xcodebuild build \
             -scheme OpenSwiftUI \
             -configuration Debug \
-            -destination "platform=iOS Simulator,OS=${{ matrix.ios-version }},name=${{ matrix.ios-simulator-name }}" \
+            -destination "platform=iOS Simulator,OS=${{ matrix.ios-version }},name=${{ matrix.ios-simulator-name }},arch=x86_64" \
             -skipMacroValidation \
             -skipPackagePluginValidation \
+            ONLY_ACTIVE_ARCH=YES \
             2>&1 | xcbeautify --renderer github-actions --preserve-unbeautified
       - name: Run test target in debug mode
         run: |
           set -o pipefail
+          # See the build step above: force x86_64 to avoid the arm64 package
+          # test runner launch/codesigning failure on this Xcode/iOS pair.
           NSUnbufferedIO=YES xcodebuild test \
             -scheme OpenSwiftUI \
             -configuration Debug \
-            -destination "platform=iOS Simulator,OS=${{ matrix.ios-version }},name=${{ matrix.ios-simulator-name }}" \
+            -destination "platform=iOS Simulator,OS=${{ matrix.ios-version }},name=${{ matrix.ios-simulator-name }},arch=x86_64" \
             -skipMacroValidation \
             -skipPackagePluginValidation \
+            ONLY_ACTIVE_ARCH=YES \
             2>&1 | xcbeautify --renderer github-actions --preserve-unbeautified

.github/workflows/macos.yml

@@ -13,7 +13,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-15]
-        xcode-version: ["16.4"]
+        xcode-version: ["26.3"]
         release: [2024]
     # Limit to self-hosted to reduce action cost
     runs-on:
@@ -43,7 +43,9 @@ jobs:
       - name: Build and run tests in debug mode with coverage
         run: |
           set -o pipefail
+          # Swift 6.2 can duplicate-link swift-syntax macro prebuilts; Swift 6.3 fixes this.
           NSUnbufferedIO=YES swift test \
+            --disable-experimental-prebuilts \
             -c debug \
             --filter OpenSwiftUITests \
             --filter OpenSwiftUICoreTests \

.github/workflows/stdout_renderer.yml

@@ -12,17 +12,13 @@ jobs:
   # stdout_renderer_linux:
   #   name: Run stdout renderer on Linux
   #   runs-on: ubuntu-22.04
-  #   container: swift:6.1.0-jammy
+  #   container: swift:6.2.4-jammy
   #   env:
   #     OPENSWIFTUI_WERROR: 0
   #     OPENSWIFTUI_SWIFT_LOG: 1
   #     OPENSWIFTUI_SWIFT_CRYPTO: 1
   #   steps:
   #     - uses: actions/checkout@v4
-  #     - name: Toolchain fix patch
-  #       run: |
-  #         # Fix swift-corelibs-foundation#5211
-  #         .github/scripts/fix-toolchain.sh
   #     - name: Run stdout renderer example
   #       run: Renderer/Stdout/run-example.sh
 
@@ -32,7 +28,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-15]
-        xcode-version: ["16.4"]
+        xcode-version: ["26.3"]
         release: [2024]
     runs-on:
       - self-hosted

.github/workflows/ubuntu.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        swift_version: ["6.1.0"]
+        swift_version: ["6.2.4"]
     runs-on: ubuntu-22.04
     env:
       OPENSWIFTUI_WERROR: 0 # Disable it to avoid enable OAG's werror and hit conflicts
@@ -24,10 +24,6 @@ jobs:
     container: swift:${{ matrix.swift_version }}-jammy
     steps:
       - uses: actions/checkout@v4
-      - name: Toolchain fix patch
-        run: |
-          # Fix swift-corelibs-foundation#5211
-          .github/scripts/fix-toolchain.sh
       - name: Building and running tests in debug mode with coverage
         run: |
           swift test \
@@ -44,4 +40,4 @@ jobs:
       - uses: codecov/codecov-action@v3
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
-          verbose: true
+          verbose: true

.github/workflows/uitests.yml

@@ -149,7 +149,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-15]
-        xcode-version: ["16.4"]
+        xcode-version: ["26.3"]
         release: [2024]
         ios-version: ["18.5"]
         renderer:
@@ -253,7 +253,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos-15]
-        xcode-version: ["16.4"]
+        xcode-version: ["26.3"]
         release: [2024]
         renderer:
           - name: SwiftUI Renderer