Share gradient stop calculations with Kotlin Multiplatform

.github/workflows/test-all.yml

@@ -41,8 +41,8 @@ jobs:
     if: github.repository == 'react/react-native'
     outputs:
       any_code_change: ${{ steps.filter_exclusions.outputs.any_code_change == 'true' || github.event_name != 'pull_request' }}
-      should_test_android: ${{ steps.filter_exclusions.outputs.should_test_android == 'true' || github.event_name != 'pull_request' }}
-      should_test_ios: ${{ steps.filter_exclusions.outputs.should_test_ios == 'true' || github.event_name != 'pull_request' }}
+      should_test_android: ${{ steps.filter_exclusions.outputs.should_test_android == 'true' || steps.filter_inclusions.outputs.react_shared == 'true' || github.event_name != 'pull_request' }}
+      should_test_ios: ${{ steps.filter_exclusions.outputs.should_test_ios == 'true' || steps.filter_inclusions.outputs.react_shared == 'true' || github.event_name != 'pull_request' }}
       debugger_shell: ${{ steps.filter_inclusions.outputs.debugger_shell }}
     steps:
       - name: Checkout
@@ -85,6 +85,9 @@ jobs:
         id: filter_inclusions
         with:
           filters: |
+            # Shared Kotlin and its build configuration affect both platforms.
+            react_shared:
+              - 'packages/react-native/ReactShared/**'
             debugger_shell:
               - 'packages/debugger-shell/**'
               - 'scripts/debugger-shell/**'

.github/workflows/test-kmp.yml

@@ -1,4 +1,4 @@
-name: Test Kotlin Multiplatform foundation
+name: Test Kotlin Multiplatform pilot
 
 on:
   workflow_dispatch:
@@ -7,7 +7,37 @@ on:
       - '.github/workflows/test-kmp.yml'
       - '.github/actions/setup-gradle/**'
       - '.github/actions/setup-xcode/**'
+      - '.github/actions/setup-node/**'
+      - '.github/actions/yarn-install/**'
+      - 'Gemfile'
+      - 'Gemfile.lock'
+      - 'build.gradle.kts'
+      - 'gradle.properties'
+      - 'gradle/wrapper/**'
+      - 'settings.gradle.kts'
+      - 'yarn.lock'
+      - 'packages/rn-tester/Podfile'
+      - 'packages/rn-tester/RCTTest/**'
+      - 'packages/rn-tester/RNTesterPods.xcodeproj/**'
+      - 'packages/rn-tester/RNTester/RNTester.xctestplan'
       - 'packages/react-native/ReactShared/**'
+      - 'packages/react-native/ReactAndroid/build.gradle.kts'
+      - 'packages/react-native/ReactAndroid/gradle.properties'
+      - 'packages/react-native/gradle/libs.versions.toml'
+      - 'packages/react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/style/ColorStop.kt'
+      - 'packages/react-native/ReactAndroid/src/test/java/com/facebook/react/uimanager/style/ColorStopTest.kt'
+      - 'packages/react-native/React/Fabric/Utils/RCTGradientUtils.*'
+      - 'packages/react-native/React/Fabric/RCTConversions.h'
+      - 'packages/react-native/Libraries/NativeAnimation/RCTAnimationUtils.*'
+      - 'packages/react-native/ReactCommon/react/renderer/graphics/**'
+      - 'packages/react-native/ReactCommon/react/utils/FloatComparison.h'
+      - 'packages/react-native/ReactCommon/react/utils/ManagedObjectWrapper.*'
+      - 'packages/react-native/React/React-RCTFabric.podspec'
+      - 'packages/react-native/scripts/react_native_pods.rb'
+      - 'packages/react-native/scripts/cocoapods/kmp.rb'
+      - 'packages/react-native/Package.swift'
+      - 'packages/react-native/package.json'
+      - 'packages/react-native/settings.gradle.kts'
   push:
     branches:
       - main
@@ -16,7 +46,37 @@ on:
       - '.github/workflows/test-kmp.yml'
       - '.github/actions/setup-gradle/**'
       - '.github/actions/setup-xcode/**'
+      - '.github/actions/setup-node/**'
+      - '.github/actions/yarn-install/**'
+      - 'Gemfile'
+      - 'Gemfile.lock'
+      - 'build.gradle.kts'
+      - 'gradle.properties'
+      - 'gradle/wrapper/**'
+      - 'settings.gradle.kts'
+      - 'yarn.lock'
+      - 'packages/rn-tester/Podfile'
+      - 'packages/rn-tester/RCTTest/**'
+      - 'packages/rn-tester/RNTesterPods.xcodeproj/**'
+      - 'packages/rn-tester/RNTester/RNTester.xctestplan'
       - 'packages/react-native/ReactShared/**'
+      - 'packages/react-native/ReactAndroid/build.gradle.kts'
+      - 'packages/react-native/ReactAndroid/gradle.properties'
+      - 'packages/react-native/gradle/libs.versions.toml'
+      - 'packages/react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/style/ColorStop.kt'
+      - 'packages/react-native/ReactAndroid/src/test/java/com/facebook/react/uimanager/style/ColorStopTest.kt'
+      - 'packages/react-native/React/Fabric/Utils/RCTGradientUtils.*'
+      - 'packages/react-native/React/Fabric/RCTConversions.h'
+      - 'packages/react-native/Libraries/NativeAnimation/RCTAnimationUtils.*'
+      - 'packages/react-native/ReactCommon/react/renderer/graphics/**'
+      - 'packages/react-native/ReactCommon/react/utils/FloatComparison.h'
+      - 'packages/react-native/ReactCommon/react/utils/ManagedObjectWrapper.*'
+      - 'packages/react-native/React/React-RCTFabric.podspec'
+      - 'packages/react-native/scripts/react_native_pods.rb'
+      - 'packages/react-native/scripts/cocoapods/kmp.rb'
+      - 'packages/react-native/Package.swift'
+      - 'packages/react-native/package.json'
+      - 'packages/react-native/settings.gradle.kts'
 
 permissions:
   contents: read
@@ -26,6 +86,227 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
+  test-shared:
+    runs-on: macos-26
+    timeout-minutes: 45
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+      - name: Set up JDK 17
+        uses: actions/setup-java@v5
+        with:
+          java-version: '17'
+          distribution: 'zulu'
+      - name: Set up Xcode for Kotlin Native
+        uses: ./.github/actions/setup-xcode
+        with:
+          xcode-version: '26.4.1'
+      - name: Set up Gradle
+        uses: ./.github/actions/setup-gradle
+      - name: Set up Ruby and CocoaPods
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.2.0'
+          bundler-cache: true
+      - name: Check CocoaPods linking configurations
+        run: bundle exec ruby packages/react-native/ReactShared/scripts/test-cocoapods-linking.rb
+      - name: Cache Kotlin Native toolchain
+        uses: actions/cache@v5
+        with:
+          path: ~/.konan
+          key: kmp-native-${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('packages/react-native/ReactShared/*.gradle.kts', 'packages/react-native/ReactShared/gradle.properties', 'packages/react-native/ReactShared/gradle/wrapper/gradle-wrapper.properties') }}
+      - name: Test shared code on JVM and iOS
+        id: shared
+        working-directory: packages/react-native/ReactShared
+        run: >-
+          ./gradlew
+          jvmTest iosSimulatorArm64Test
+          linkDebugFrameworkIosArm64 linkReleaseFrameworkIosArm64
+          linkDebugFrameworkIosSimulatorArm64 linkReleaseFrameworkIosSimulatorArm64
+          linkDebugFrameworkIosX64 linkReleaseFrameworkIosX64
+          --stacktrace --console=plain
+      - name: Compare the Apple adapter with native gradients
+        if: ${{ !cancelled() && steps.shared.outcome == 'success' }}
+        working-directory: packages/react-native/ReactShared
+        run: ./scripts/test-apple-gradient.sh
+      - name: Compare optimized Apple gradients
+        if: ${{ !cancelled() && steps.shared.outcome == 'success' }}
+        working-directory: packages/react-native/ReactShared
+        env:
+          RCT_KMP_BUILD_TYPE: Release
+        run: ./scripts/test-apple-gradient.sh
+      - name: Test packaged XCFramework consumption
+        if: ${{ !cancelled() && steps.shared.outcome == 'success' }}
+        working-directory: packages/react-native/ReactShared
+        run: ./scripts/test-apple-distribution.sh
+      - name: Test independent Kotlin runtime coexistence
+        if: ${{ !cancelled() && steps.shared.outcome == 'success' }}
+        working-directory: packages/react-native/ReactShared
+        run: python3 scripts/test-kotlin-coexistence.py
+      - name: Measure native gradient costs
+        if: ${{ !cancelled() && steps.shared.outcome == 'success' }}
+        working-directory: packages/react-native/ReactShared
+        run: python3 scripts/benchmark-apple-gradient.py
+      - name: Measure clean and incremental shared builds
+        if: ${{ !cancelled() && steps.shared.outcome == 'success' }}
+        working-directory: packages/react-native/ReactShared
+        run: python3 scripts/benchmark-kmp-build.py
+      - name: Upload test reports
+        if: always()
+        uses: actions/upload-artifact@v6
+        with:
+          name: kotlin-multiplatform-test-results
+          path: |
+            packages/react-native/ReactShared/build/reports/tests
+            packages/react-native/ReactShared/build/test-results
+            packages/react-native/ReactShared/build/apple-distribution/**/*.json
+            packages/react-native/ReactShared/build/apple-distribution/**/*.log
+            packages/react-native/ReactShared/build/apple-distribution/**/consumer.xcresult
+            packages/react-native/ReactShared/build/kotlin-coexistence/**/*.json
+            packages/react-native/ReactShared/build/kotlin-coexistence/**/*.log
+            packages/react-native/ReactShared/build/apple-gradient-benchmark/**/*.json
+            packages/react-native/ReactShared/build/apple-gradient-benchmark/**/*.log
+            packages/react-native/ReactShared/build/kmp-build-benchmark/**/*.json
+            packages/react-native/ReactShared/build/kmp-build-benchmark/**/*.log
+          if-no-files-found: warn
+
+  test-android-consumers:
+    name: Android Maven and npm source consumers
+    runs-on: 8-core-ubuntu
+    timeout-minutes: 90
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+      - name: Set up Node
+        uses: ./.github/actions/setup-node
+      - name: Install JavaScript dependencies
+        uses: ./.github/actions/yarn-install
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - name: Set up JDK 17
+        uses: actions/setup-java@v5
+        with:
+          java-version: '17'
+          distribution: 'zulu'
+      - name: Set up Gradle
+        uses: ./.github/actions/setup-gradle
+      - name: Install Android build SDK
+        id: android-sdk
+        run: |
+          python3 - <<'PY'
+          import os, pathlib, re, shutil, subprocess, tomllib
+          versions = tomllib.loads(pathlib.Path('packages/react-native/gradle/libs.versions.toml').read_text())['versions']
+          sdkmanager = shutil.which('sdkmanager') or str(pathlib.Path(os.environ['ANDROID_HOME']) / 'cmdline-tools/latest/bin/sdkmanager')
+          packages = subprocess.check_output([sdkmanager, '--list'], text=True)
+          base = 'platforms;android-' + versions['compileSdk']
+          # Recent SDKs use a minor version in their package ID (for example android-37.0).
+          platform = next((name for name in [base + '.0', base] if re.search(r'^\s*' + re.escape(name) + r'\s*\|', packages, re.M)), None)
+          if platform is None:
+              raise SystemExit('No Android SDK package matches compileSdk ' + versions['compileSdk'])
+          subprocess.run([sdkmanager, platform, 'build-tools;' + versions['buildTools']], check=True)
+          with open(os.environ['GITHUB_OUTPUT'], 'a') as output:
+              output.write('ndk=' + versions['ndkVersion'] + '\n')
+          PY
+      - name: Enable emulator hardware acceleration
+        run: |
+          echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
+          sudo udevadm control --reload-rules
+          sudo udevadm trigger --name-match=kvm
+      - name: Build and run packaged Android consumers
+        uses: reactivecircus/android-emulator-runner@v2
+        with:
+          api-level: 35
+          target: google_apis
+          arch: x86_64
+          ndk: ${{ steps.android-sdk.outputs.ndk }}
+          cmake: 3.30.5
+          cores: 4
+          disable-animations: true
+          script: python3 packages/react-native/ReactShared/scripts/test-android-consumers.py --output-dir "$RUNNER_TEMP/kmp-android-consumers" --abi x86_64 --device emulator-5554
+      - name: Upload consumer reports
+        if: always()
+        uses: actions/upload-artifact@v6
+        with:
+          name: kmp-android-consumers
+          path: |
+            ${{ runner.temp }}/kmp-android-consumers/*.log
+            ${{ runner.temp }}/kmp-android-consumers/*.json
+          if-no-files-found: warn
+
+  test-apple-app:
+    name: RNTester KMP ${{ matrix.platform }} (${{ matrix.linkage }})
+    runs-on: macos-26
+    timeout-minutes: 90
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - platform: simulator
+            linkage: libraries
+          - platform: simulator
+            linkage: static
+          - platform: simulator
+            linkage: dynamic
+          - platform: device
+            linkage: libraries
+          - platform: catalyst
+            linkage: libraries
+    env:
+      RCT_KMP_APP_OUTPUT_DIR: ${{ github.workspace }}/packages/react-native/ReactShared/build/apple-app-results
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+      - name: Set up Node
+        uses: ./.github/actions/setup-node
+      - name: Install JavaScript dependencies
+        uses: ./.github/actions/yarn-install
+      - name: Select the Hermes compiler package
+        run: node scripts/releases/use-hermes-prebuilt.js
+      - name: Install the selected Hermes compiler
+        uses: ./.github/actions/yarn-install
+      - name: Set up JDK 17
+        uses: actions/setup-java@v5
+        with:
+          java-version: '17'
+          distribution: 'zulu'
+      - name: Set up Xcode for Kotlin Native
+        uses: ./.github/actions/setup-xcode
+        with:
+          xcode-version: '26.4.1'
+      - name: Set up Gradle
+        uses: ./.github/actions/setup-gradle
+      - name: Set up Ruby and CocoaPods
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.2.0'
+          bundler-cache: true
+      - name: Cache Kotlin Native toolchain
+        uses: actions/cache@v5
+        with:
+          path: ~/.konan
+          key: kmp-native-${{ runner.os }}-${{ runner.arch }}-${{ hashFiles('packages/react-native/ReactShared/*.gradle.kts', 'packages/react-native/ReactShared/gradle.properties', 'packages/react-native/ReactShared/gradle/wrapper/gradle-wrapper.properties') }}
+      - name: Build and validate the KMP source application
+        run: |
+          if [[ '${{ matrix.linkage }}' != libraries ]]; then
+            export USE_FRAMEWORKS='${{ matrix.linkage }}'
+          fi
+          ./packages/react-native/ReactShared/scripts/test-apple-app.sh '${{ matrix.platform }}'
+      - name: Upload application test reports
+        if: always()
+        uses: actions/upload-artifact@v6
+        with:
+          name: kmp-app-${{ matrix.platform }}-${{ matrix.linkage }}
+          path: |
+            ${{ env.RCT_KMP_APP_OUTPUT_DIR }}/*.log
+            ${{ env.RCT_KMP_APP_OUTPUT_DIR }}/*.json
+            ${{ env.RCT_KMP_APP_OUTPUT_DIR }}/*.txt
+            ${{ env.RCT_KMP_APP_OUTPUT_DIR }}/*.xcresult
+            ${{ env.RCT_KMP_APP_OUTPUT_DIR }}/Podfile*
+            ${{ env.RCT_KMP_APP_OUTPUT_DIR }}/project.pbxproj
+          if-no-files-found: warn
+
   smoke:
     runs-on: macos-26
     timeout-minutes: 45

build.gradle.kts

@@ -72,6 +72,7 @@ nexusPublishing {
 tasks.register("clean", Delete::class.java) {
   description = "Remove all the build files and intermediate build outputs"
   dependsOn(gradle.includedBuild("gradle-plugin").task(":clean"))
+  dependsOn(gradle.includedBuild("react-native-shared").task(":clean"))
   subprojects.forEach {
     if (
         it.project.plugins.hasPlugin("com.android.library") ||
@@ -103,6 +104,7 @@ tasks.register("clean", Delete::class.java) {
 tasks.register("build") {
   description = "Build and test all the React Native relevant projects."
   dependsOn(gradle.includedBuild("gradle-plugin").task(":build"))
+  dependsOn(gradle.includedBuild("react-native-shared").task(":jvmTest"))
 }
 
 tasks.register("publishAllToMavenTempLocal") {

packages/react-native/Package.swift

@@ -9,6 +9,10 @@
 import Foundation
 import PackageDescription
 
+if ProcessInfo.processInfo.environment["RCT_USE_KMP"] == "1" {
+  fatalError("RCT_USE_KMP=1 currently supports CocoaPods source builds only. Run RCT_USE_KMP=1 pod install in the iOS app; the SwiftPM prebuild does not include ReactNativeShared.")
+}
+
 let BUILD_FROM_SOURCE = false
 
 // Removing the legacy TurboModule and component interop layers is opt-in while those