Update `flutter_tools` internals related to Gradle/XCode to set `--local-engine-host`. (#132346)

Partial work towards https://github.com/flutter/flutter/issues/132245.

I made a minor refactor to test-only code because it was too confusing
to have 2 optional parameters that are technically required together,
but otherwise all other changes *should* be pass throughs. That being
said, I can't say I totally understand the Gradle stuff so I could use a
hand double checking that.

packages/flutter_tools/gradle/src/main/groovy/flutter.groovy

@@ -164,6 +164,7 @@ class FlutterPlugin implements Plugin<Project> {
     private File flutterRoot
     private File flutterExecutable
     private String localEngine
+    private String localEngineHost
     private String localEngineSrcPath
     private Properties localProperties
     private String engineVersion
@@ -324,6 +325,13 @@ class FlutterPlugin implements Plugin<Project> {
             }
             localEngine = engineOut.name
             localEngineSrcPath = engineOut.parentFile.parent
+
+            String engineHostOutPath = project.property('local-engine-host-out')
+            File engineHostOut = project.file(engineHostOutPath)
+            if (!engineHostOut.isDirectory()) {
+                throw new GradleException('local-engine-host-out must point to a local engine host build')
+            }
+            localEngineHostOut = engineHostOut.name
         }
         project.android.buildTypes.all this.&addFlutterDependencies
     }
@@ -1027,6 +1035,7 @@ class FlutterPlugin implements Plugin<Project> {
                 flutterExecutable this.flutterExecutable
                 buildMode variantBuildMode
                 localEngine this.localEngine
+                localEngineHost this.localEngineHost
                 localEngineSrcPath this.localEngineSrcPath
                 targetPath getFlutterTarget()
                 verbose this.isVerbose()
@@ -1235,6 +1244,8 @@ abstract class BaseFlutterTask extends DefaultTask {
     @Optional @Input
     String localEngine
     @Optional @Input
+    String localEngineHost
+    @Optional @Input
     String localEngineSrcPath
     @Optional @Input
     Boolean fastStart
@@ -1313,6 +1324,9 @@ abstract class BaseFlutterTask extends DefaultTask {
                 args "--local-engine", localEngine
                 args "--local-engine-src-path", localEngineSrcPath
             }
+            if (localEngineHost != null) {
+                args "--local-engine-host", localEngineHost
+            }
             if (verbose) {
                 args "--verbose"
             } else {

packages/flutter_tools/lib/src/android/gradle.dart

@@ -401,6 +401,7 @@ class AndroidGradleBuilder implements AndroidBuilder {
       command.add('-Plocal-engine-repo=${localEngineRepo.path}');
       command.add('-Plocal-engine-build-mode=${buildInfo.modeName}');
       command.add('-Plocal-engine-out=${localEngineInfo.engineOutPath}');
+      command.add('-Plocal-engine-host-out=${localEngineInfo.engineHostOutPath}');
       command.add('-Ptarget-platform=${_getTargetPlatformByLocalEnginePath(
           localEngineInfo.engineOutPath)}');
     } else if (androidBuildInfo.targetArchs.isNotEmpty) {
@@ -726,6 +727,7 @@ class AndroidGradleBuilder implements AndroidBuilder {
       command.add('-Plocal-engine-repo=${localEngineRepo.path}');
       command.add('-Plocal-engine-build-mode=${buildInfo.modeName}');
       command.add('-Plocal-engine-out=${localEngineInfo.engineOutPath}');
+      command.add('-Plocal-engine-host-out=${localEngineInfo.engineHostOutPath}');
 
       // Copy the local engine repo in the output directory.
       try {

packages/flutter_tools/lib/src/artifacts.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:file/memory.dart';
+import 'package:meta/meta.dart';
 import 'package:process/process.dart';
 
 import 'base/common.dart';
@@ -287,10 +288,12 @@ class EngineBuildPaths {
 class LocalEngineInfo {
   const LocalEngineInfo({
     required this.engineOutPath,
+    required this.engineHostOutPath,
     required this.localEngineName,
   });
 
   final String engineOutPath;
+  final String engineHostOutPath;
   final String localEngineName;
 }
 
@@ -302,12 +305,23 @@ abstract class Artifacts {
   /// If a [fileSystem] is not provided, creates a new [MemoryFileSystem] instance.
   ///
   /// Creates a [LocalEngineArtifacts] if `localEngine` is non-null
-  factory Artifacts.test({String? localEngine, FileSystem? fileSystem}) {
-    fileSystem ??= MemoryFileSystem.test();
-    if (localEngine != null) {
-      return _TestLocalEngine(localEngine, fileSystem);
-    }
-    return _TestArtifacts(fileSystem);
+  @visibleForTesting
+  factory Artifacts.test({FileSystem? fileSystem}) {
+    return _TestArtifacts(fileSystem ?? MemoryFileSystem.test());
+  }
+
+  /// A test-specific implementation of artifacts that returns stable paths for
+  /// all artifacts, and uses a local engine.
+  ///
+  /// If a [fileSystem] is not provided, creates a new [MemoryFileSystem] instance.
+  @visibleForTesting
+  factory Artifacts.testLocalEngine({
+    required String localEngine,
+    required String localEngineHost,
+    FileSystem? fileSystem,
+  }) {
+    return _TestLocalEngine(
+        localEngine, localEngineHost, fileSystem ?? MemoryFileSystem.test());
   }
 
   static Artifacts getLocalEngine(EngineBuildPaths engineBuildPaths) {
@@ -811,6 +825,7 @@ class CachedLocalEngineArtifacts implements Artifacts {
        localEngineInfo =
          LocalEngineInfo(
            engineOutPath: engineOutPath,
+           engineHostOutPath: _hostEngineOutPath,
            localEngineName: fileSystem.path.basename(engineOutPath)
          ),
        _cache = cache,
@@ -1365,12 +1380,12 @@ class _TestArtifacts implements Artifacts {
 }
 
 class _TestLocalEngine extends _TestArtifacts {
-  _TestLocalEngine(String engineOutPath, super.fileSystem) :
-    localEngineInfo =
-      LocalEngineInfo(
-        engineOutPath: engineOutPath,
-        localEngineName: fileSystem.path.basename(engineOutPath)
-      );
+  _TestLocalEngine(
+      String engineOutPath, String engineHostOutPath, super.fileSystem)
+      : localEngineInfo = LocalEngineInfo(
+            engineOutPath: engineOutPath,
+            engineHostOutPath: engineHostOutPath,
+            localEngineName: fileSystem.path.basename(engineOutPath));
 
   @override
   bool get isLocalEngine => true;

packages/flutter_tools/lib/src/ios/mac.dart

@@ -72,6 +72,7 @@ class IMobileDevice {
   /// Create an [IMobileDevice] for testing.
   factory IMobileDevice.test({ required ProcessManager processManager }) {
     return IMobileDevice(
+      // ignore: invalid_use_of_visible_for_testing_member
       artifacts: Artifacts.test(),
       cache: Cache.test(processManager: processManager),
       processManager: processManager,

packages/flutter_tools/test/commands.shard/hermetic/assemble_test.dart

@@ -192,7 +192,7 @@ void main() {
     ));
     await commandRunner.run(<String>['assemble', '-o Output', 'debug_macos_bundle_flutter_assets']);
   }, overrides: <Type, Generator>{
-    Artifacts: () => Artifacts.test(localEngine: 'out/host_release'),
+    Artifacts: () => Artifacts.testLocalEngine(localEngine: 'out/host_release', localEngineHost: 'out/host_release'),
     Cache: () => Cache.test(processManager: FakeProcessManager.any()),
     FileSystem: () => MemoryFileSystem.test(),
     ProcessManager: () => FakeProcessManager.any(),

packages/flutter_tools/test/general.shard/android/android_gradle_builder_test.dart

@@ -1187,7 +1187,7 @@ unknown crash
         logger: logger,
         processManager: processManager,
         fileSystem: fileSystem,
-        artifacts: Artifacts.test(localEngine: 'out/android_arm'),
+        artifacts: Artifacts.testLocalEngine(localEngine: 'out/android_arm', localEngineHost: 'out/host_release'),
         usage: testUsage,
         gradleUtils: FakeGradleUtils(),
         platform: FakePlatform(),
@@ -1200,6 +1200,7 @@ unknown crash
           '-Plocal-engine-repo=/.tmp_rand0/flutter_tool_local_engine_repo.rand0',
           '-Plocal-engine-build-mode=release',
           '-Plocal-engine-out=out/android_arm',
+          '-Plocal-engine-host-out=out/host_release',
           '-Ptarget-platform=android-arm',
           '-Ptarget=lib/main.dart',
           '-Pbase-application-name=io.flutter.app.FlutterApplication',
@@ -1266,7 +1267,7 @@ unknown crash
         logger: logger,
         processManager: processManager,
         fileSystem: fileSystem,
-        artifacts: Artifacts.test(localEngine: 'out/android_arm64'),
+        artifacts: Artifacts.testLocalEngine(localEngine: 'out/android_arm64', localEngineHost: 'out/host_release'),
         usage: testUsage,
         gradleUtils: FakeGradleUtils(),
         platform: FakePlatform(),
@@ -1279,6 +1280,7 @@ unknown crash
           '-Plocal-engine-repo=/.tmp_rand0/flutter_tool_local_engine_repo.rand0',
           '-Plocal-engine-build-mode=release',
           '-Plocal-engine-out=out/android_arm64',
+          '-Plocal-engine-host-out=out/host_release',
           '-Ptarget-platform=android-arm64',
           '-Ptarget=lib/main.dart',
           '-Pbase-application-name=io.flutter.app.FlutterApplication',
@@ -1345,7 +1347,7 @@ unknown crash
         logger: logger,
         processManager: processManager,
         fileSystem: fileSystem,
-        artifacts: Artifacts.test(localEngine: 'out/android_x86'),
+        artifacts: Artifacts.testLocalEngine(localEngine: 'out/android_x86', localEngineHost: 'out/host_release'),
         usage: testUsage,
         gradleUtils: FakeGradleUtils(),
         platform: FakePlatform(),
@@ -1358,6 +1360,7 @@ unknown crash
           '-Plocal-engine-repo=/.tmp_rand0/flutter_tool_local_engine_repo.rand0',
           '-Plocal-engine-build-mode=release',
           '-Plocal-engine-out=out/android_x86',
+          '-Plocal-engine-host-out=out/host_release',
           '-Ptarget-platform=android-x86',
           '-Ptarget=lib/main.dart',
           '-Pbase-application-name=io.flutter.app.FlutterApplication',
@@ -1424,7 +1427,7 @@ unknown crash
         logger: logger,
         processManager: processManager,
         fileSystem: fileSystem,
-        artifacts: Artifacts.test(localEngine: 'out/android_x64'),
+        artifacts: Artifacts.testLocalEngine(localEngine: 'out/android_x64', localEngineHost: 'out/host_release'),
         usage: testUsage,
         gradleUtils: FakeGradleUtils(),
         platform: FakePlatform(),
@@ -1437,6 +1440,7 @@ unknown crash
           '-Plocal-engine-repo=/.tmp_rand0/flutter_tool_local_engine_repo.rand0',
           '-Plocal-engine-build-mode=release',
           '-Plocal-engine-out=out/android_x64',
+          '-Plocal-engine-host-out=out/host_release',
           '-Ptarget-platform=android-x64',
           '-Ptarget=lib/main.dart',
           '-Pbase-application-name=io.flutter.app.FlutterApplication',
@@ -1565,7 +1569,7 @@ unknown crash
         logger: logger,
         processManager: processManager,
         fileSystem: fileSystem,
-        artifacts: Artifacts.test(localEngine: 'out/android_arm'),
+        artifacts: Artifacts.testLocalEngine(localEngine: 'out/android_arm', localEngineHost: 'out/host_release'),
         usage: testUsage,
         gradleUtils: FakeGradleUtils(),
         platform: FakePlatform(),
@@ -1586,6 +1590,7 @@ unknown crash
           '-Plocal-engine-repo=/.tmp_rand0/flutter_tool_local_engine_repo.rand0',
           '-Plocal-engine-build-mode=release',
           '-Plocal-engine-out=out/android_arm',
+          '-Plocal-engine-host-out=out/host_release',
           '-Ptarget-platform=android-arm',
           'assembleAarRelease',
         ],
@@ -1653,7 +1658,7 @@ unknown crash
         logger: logger,
         processManager: processManager,
         fileSystem: fileSystem,
-        artifacts: Artifacts.test(localEngine: 'out/android_arm64'),
+        artifacts: Artifacts.testLocalEngine(localEngine: 'out/android_arm64', localEngineHost: 'out/host_release'),
         usage: testUsage,
         gradleUtils: FakeGradleUtils(),
         platform: FakePlatform(),
@@ -1674,6 +1679,7 @@ unknown crash
           '-Plocal-engine-repo=/.tmp_rand0/flutter_tool_local_engine_repo.rand0',
           '-Plocal-engine-build-mode=release',
           '-Plocal-engine-out=out/android_arm64',
+          '-Plocal-engine-host-out=out/host_release',
           '-Ptarget-platform=android-arm64',
           'assembleAarRelease',
         ],
@@ -1741,7 +1747,7 @@ unknown crash
         logger: logger,
         processManager: processManager,
         fileSystem: fileSystem,
-        artifacts: Artifacts.test(localEngine: 'out/android_x86'),
+        artifacts: Artifacts.testLocalEngine(localEngine: 'out/android_x86', localEngineHost: 'out/host_release'),
         usage: testUsage,
         gradleUtils: FakeGradleUtils(),
         platform: FakePlatform(),
@@ -1762,6 +1768,7 @@ unknown crash
           '-Plocal-engine-repo=/.tmp_rand0/flutter_tool_local_engine_repo.rand0',
           '-Plocal-engine-build-mode=release',
           '-Plocal-engine-out=out/android_x86',
+          '-Plocal-engine-host-out=out/host_release',
           '-Ptarget-platform=android-x86',
           'assembleAarRelease',
         ],
@@ -1829,7 +1836,7 @@ unknown crash
         logger: logger,
         processManager: processManager,
         fileSystem: fileSystem,
-        artifacts: Artifacts.test(localEngine: 'out/android_x64'),
+        artifacts: Artifacts.testLocalEngine(localEngine: 'out/android_x64', localEngineHost: 'out/host_release'),
         usage: testUsage,
         gradleUtils: FakeGradleUtils(),
         platform: FakePlatform(),
@@ -1850,6 +1857,7 @@ unknown crash
           '-Plocal-engine-repo=/.tmp_rand0/flutter_tool_local_engine_repo.rand0',
           '-Plocal-engine-build-mode=release',
           '-Plocal-engine-out=out/android_x64',
+          '-Plocal-engine-host-out=out/host_release',
           '-Ptarget-platform=android-x64',
           'assembleAarRelease',
         ],

packages/flutter_tools/test/general.shard/android/gradle_test.dart

@@ -211,7 +211,7 @@ void main() {
 
     setUp(() {
       fs = MemoryFileSystem.test();
-      localEngineArtifacts = Artifacts.test(localEngine: 'out/android_arm');
+      localEngineArtifacts = Artifacts.testLocalEngine(localEngine: 'out/android_arm', localEngineHost: 'out/host_release');
     });
 
     void testUsingAndroidContext(String description, dynamic Function() testMethod) {

packages/flutter_tools/test/general.shard/build_info_test.dart

@@ -104,17 +104,17 @@ void main() {
   testWithoutContext('defaultIOSArchsForEnvironment', () {
     expect(defaultIOSArchsForEnvironment(
       EnvironmentType.physical,
-      Artifacts.test(localEngine: 'ios_debug_unopt'),
+      Artifacts.testLocalEngine(localEngineHost: 'host_debug_unopt', localEngine: 'ios_debug_unopt'),
     ).single, DarwinArch.arm64);
 
     expect(defaultIOSArchsForEnvironment(
       EnvironmentType.simulator,
-      Artifacts.test(localEngine: 'ios_debug_sim_unopt'),
+      Artifacts.testLocalEngine(localEngineHost: 'host_debug_unopt', localEngine: 'ios_debug_sim_unopt'),
     ).single, DarwinArch.x86_64);
 
     expect(defaultIOSArchsForEnvironment(
       EnvironmentType.simulator,
-      Artifacts.test(localEngine: 'ios_debug_sim_unopt_arm64'),
+      Artifacts.testLocalEngine(localEngineHost: 'host_debug_unopt', localEngine: 'ios_debug_sim_unopt_arm64'),
     ).single, DarwinArch.arm64);
 
     expect(defaultIOSArchsForEnvironment(
@@ -128,11 +128,11 @@ void main() {
 
   testWithoutContext('defaultMacOSArchsForEnvironment', () {
     expect(defaultMacOSArchsForEnvironment(
-      Artifacts.test(localEngine: 'host_debug_unopt'),
+      Artifacts.testLocalEngine(localEngineHost: 'host_debug_unopt', localEngine: 'host_debug_unopt'),
     ).single, DarwinArch.x86_64);
 
     expect(defaultMacOSArchsForEnvironment(
-      Artifacts.test(localEngine: 'host_debug_unopt_arm64'),
+      Artifacts.testLocalEngine(localEngineHost: 'host_debug_unopt', localEngine: 'host_debug_unopt_arm64'),
     ).single, DarwinArch.arm64);
 
     expect(defaultMacOSArchsForEnvironment(

packages/flutter_tools/test/general.shard/ios/xcodeproj_test.dart

@@ -754,7 +754,7 @@ Information about project "Runner":
 
     setUp(() {
       fs = MemoryFileSystem.test();
-      localIosArtifacts = Artifacts.test(localEngine: 'out/ios_profile_arm64');
+      localIosArtifacts = Artifacts.testLocalEngine(localEngine: 'out/ios_profile_arm64', localEngineHost: 'out/host_release');
       macOS = FakePlatform(operatingSystem: 'macos');
       fs.file(xcodebuild).createSync(recursive: true);
     });
@@ -938,7 +938,7 @@ Build settings for action build and target plugin2:
     }
 
     testUsingOsxContext('exits when armv7 local engine is set', () async {
-      localIosArtifacts = Artifacts.test(localEngine: 'out/ios_profile_arm');
+      localIosArtifacts = Artifacts.testLocalEngine(localEngine: 'out/ios_profile_arm', localEngineHost: 'out/host_release');
       const BuildInfo buildInfo = BuildInfo.debug;
       final FlutterProject project = FlutterProject.fromDirectoryTest(fs.directory('path/to/project'));
       await expectLater(() =>
@@ -971,7 +971,7 @@ Build settings for action build and target plugin2:
       final String buildPhaseScriptContents = buildPhaseScript.readAsStringSync();
       expect(buildPhaseScriptContents.contains('export "ARCHS=arm64"'), isTrue);
     }, overrides: <Type, Generator>{
-      Artifacts: () => Artifacts.test(localEngine: 'out/host_profile_arm64'),
+      Artifacts: () => Artifacts.testLocalEngine(localEngine: 'out/host_profile_arm64', localEngineHost: 'out/host_release'),
       Platform: () => macOS,
       FileSystem: () => fs,
       ProcessManager: () => FakeProcessManager.any(),
@@ -998,7 +998,7 @@ Build settings for action build and target plugin2:
       final String buildPhaseScriptContents = buildPhaseScript.readAsStringSync();
       expect(buildPhaseScriptContents.contains('export "ARCHS=x86_64"'), isTrue);
     }, overrides: <Type, Generator>{
-      Artifacts: () => Artifacts.test(localEngine: 'out/host_profile'),
+      Artifacts: () => Artifacts.testLocalEngine(localEngine: 'out/host_profile', localEngineHost: 'out/host_release'),
       Platform: () => macOS,
       FileSystem: () => fs,
       ProcessManager: () => FakeProcessManager.any(),
@@ -1083,7 +1083,7 @@ Build settings for action build and target plugin2:
         final String buildPhaseScriptContents = buildPhaseScript.readAsStringSync();
         expect(buildPhaseScriptContents.contains('ARCHS=x86_64'), isTrue);
       }, overrides: <Type, Generator>{
-        Artifacts: () => Artifacts.test(localEngine: 'out/ios_debug_sim_unopt'),
+        Artifacts: () => Artifacts.testLocalEngine(localEngine: 'out/ios_debug_sim_unopt', localEngineHost: 'out/host_debug_unopt'),
         Platform: () => macOS,
         FileSystem: () => fs,
         ProcessManager: () => FakeProcessManager.any(),
@@ -1109,7 +1109,7 @@ Build settings for action build and target plugin2:
         final String buildPhaseScriptContents = buildPhaseScript.readAsStringSync();
         expect(buildPhaseScriptContents.contains('ARCHS=arm64'), isTrue);
       }, overrides: <Type, Generator>{
-        Artifacts: () => Artifacts.test(localEngine: 'out/ios_debug_sim_arm64'),
+        Artifacts: () => Artifacts.testLocalEngine(localEngine: 'out/ios_debug_sim_arm64', localEngineHost: 'out/host_debug_unopt'),
         Platform: () => macOS,
         FileSystem: () => fs,
         ProcessManager: () => FakeProcessManager.any(),