Fix --local-engine for the new web/wasm mode (#113759)

packages/flutter_tools/lib/src/artifacts.dart

@@ -768,24 +768,22 @@ class CachedLocalEngineArtifacts implements LocalEngineArtifacts {
 
 
   @override
-  FileSystemEntity getHostArtifact(
-    HostArtifact artifact,
-  ) {
+  FileSystemEntity getHostArtifact(HostArtifact artifact) {
     switch (artifact) {
       case HostArtifact.engineDartSdkPath:
-        final String path = _fileSystem.path.join(_hostEngineOutPath, 'dart-sdk');
+        final String path = _getDartSdkPath();
         return _fileSystem.directory(path);
       case HostArtifact.engineDartBinary:
-        final String path = _fileSystem.path.join(_hostEngineOutPath, 'dart-sdk', 'bin', _hostArtifactToFileName(artifact, _platform));
+        final String path = _fileSystem.path.join(_getDartSdkPath(), 'bin', _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
       case HostArtifact.dart2jsSnapshot:
-        final String path = _fileSystem.path.join(_hostEngineOutPath, 'dart-sdk', 'bin', 'snapshots', _hostArtifactToFileName(artifact, _platform));
+        final String path = _fileSystem.path.join(_getDartSdkPath(), 'bin', 'snapshots', _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
       case HostArtifact.dartdevcSnapshot:
-        final String path = _fileSystem.path.join(_dartSdkPath(_cache), 'bin', 'snapshots', _hostArtifactToFileName(artifact, _platform));
+        final String path = _fileSystem.path.join(_getDartSdkPath(), 'bin', 'snapshots', _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
       case HostArtifact.kernelWorkerSnapshot:
-        final String path = _fileSystem.path.join(_hostEngineOutPath, 'dart-sdk', 'bin', 'snapshots', _hostArtifactToFileName(artifact, _platform));
+        final String path = _fileSystem.path.join(_getDartSdkPath(), 'bin', 'snapshots', _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
       case HostArtifact.flutterWebSdk:
         final String path = _getFlutterWebSdkPath();
@@ -908,7 +906,7 @@ class CachedLocalEngineArtifacts implements LocalEngineArtifacts {
         return _fileSystem.path.join(_hostEngineOutPath, artifactFileName);
       case Artifact.frontendServerSnapshotForEngineDartSdk:
         return _fileSystem.path.join(
-          _hostEngineOutPath, 'dart-sdk', 'bin', 'snapshots', artifactFileName,
+          _getDartSdkPath(), 'bin', 'snapshots', artifactFileName,
         );
     }
   }
@@ -923,6 +921,51 @@ class CachedLocalEngineArtifacts implements LocalEngineArtifacts {
         buildMode == BuildMode.release ? 'flutter_patched_sdk_product' : 'flutter_patched_sdk');
   }
 
+  String _getDartSdkPath() {
+    final String builtPath = _fileSystem.path.join(_hostEngineOutPath, 'dart-sdk');
+    if (_fileSystem.isDirectorySync(_fileSystem.path.join(builtPath, 'bin'))) {
+      return builtPath;
+    }
+
+    // If we couldn't find a built dart sdk, let's look for a prebuilt one.
+    final String prebuiltPath = _fileSystem.path.join(_getFlutterPrebuiltsPath(), _getPrebuiltTarget(), 'dart-sdk');
+    if (_fileSystem.isDirectorySync(prebuiltPath)) {
+      return prebuiltPath;
+    }
+
+    throw ToolExit('Unable to find a built dart sdk at: "$builtPath" or a prebuilt dart sdk at: "$prebuiltPath"');
+  }
+
+  String _getFlutterPrebuiltsPath() {
+    final String engineSrcPath = _fileSystem.path.dirname(_fileSystem.path.dirname(_hostEngineOutPath));
+    return _fileSystem.path.join(engineSrcPath, 'flutter', 'prebuilts');
+  }
+
+  String _getPrebuiltTarget() {
+    final TargetPlatform hostPlatform = _currentHostPlatform(_platform, _operatingSystemUtils);
+    switch (hostPlatform) {
+      case TargetPlatform.darwin:
+        return 'macos-x64';
+      case TargetPlatform.linux_arm64:
+        return 'linux-arm64';
+      case TargetPlatform.linux_x64:
+        return 'linux-x64';
+      case TargetPlatform.windows_x64:
+        return 'windows-x64';
+      case TargetPlatform.ios:
+      case TargetPlatform.android:
+      case TargetPlatform.android_arm:
+      case TargetPlatform.android_arm64:
+      case TargetPlatform.android_x64:
+      case TargetPlatform.android_x86:
+      case TargetPlatform.fuchsia_arm64:
+      case TargetPlatform.fuchsia_x64:
+      case TargetPlatform.web_javascript:
+      case TargetPlatform.tester:
+        throwToolExit('Unsupported host platform: $hostPlatform');
+    }
+  }
+
   String _getFlutterWebSdkPath() {
     return _fileSystem.path.join(engineOutPath, 'flutter_web_sdk');
   }

packages/flutter_tools/lib/src/asset.dart

@@ -252,6 +252,7 @@ class ManifestAssetBundle implements AssetBundle {
       flutterManifest,
       wildcardDirectories,
       assetBasePath,
+      targetPlatform,
     );
 
     if (assetVariants == null) {
@@ -316,6 +317,7 @@ class ManifestAssetBundle implements AssetBundle {
           // Do not track wildcard directories for dependencies.
           <Uri>[],
           packageBasePath,
+          targetPlatform,
           packageName: package.name,
           attributedPackage: package,
         );
@@ -407,10 +409,11 @@ class ManifestAssetBundle implements AssetBundle {
     final List<_Asset> materialAssets = <_Asset>[
       if (flutterManifest.usesMaterialDesign)
         ..._getMaterialFonts(),
-      // Include the shaders unconditionally. They are small, and whether
-      // they're used is determined only by the app source code and not by
-      // the Flutter manifest.
-      ..._getMaterialShaders(),
+      // For non-web platforms, include the shaders unconditionally. They are
+      // small, and whether they're used is determined only by the app source
+      // code and not by the Flutter manifest.
+      if (targetPlatform != TargetPlatform.web_javascript)
+        ..._getMaterialShaders(),
     ];
     for (final _Asset asset in materialAssets) {
       final File assetFile = asset.lookupAssetFile(_fileSystem);
@@ -716,7 +719,8 @@ class ManifestAssetBundle implements AssetBundle {
     PackageConfig packageConfig,
     FlutterManifest flutterManifest,
     List<Uri> wildcardDirectories,
-    String assetBase, {
+    String assetBase,
+    TargetPlatform? targetPlatform, {
     String? packageName,
     Package? attributedPackage,
   }) {
@@ -750,18 +754,21 @@ class ManifestAssetBundle implements AssetBundle {
       }
     }
 
-    for (final Uri shaderUri in flutterManifest.shaders) {
-      _parseAssetFromFile(
-        packageConfig,
-        flutterManifest,
-        assetBase,
-        cache,
-        result,
-        shaderUri,
-        packageName: packageName,
-        attributedPackage: attributedPackage,
-        assetKind: AssetKind.shader,
-      );
+    // No shader compilation for the web.
+    if (targetPlatform != TargetPlatform.web_javascript) {
+      for (final Uri shaderUri in flutterManifest.shaders) {
+        _parseAssetFromFile(
+          packageConfig,
+          flutterManifest,
+          assetBase,
+          cache,
+          result,
+          shaderUri,
+          packageName: packageName,
+          attributedPackage: attributedPackage,
+          assetKind: AssetKind.shader,
+        );
+      }
     }
 
     // Add assets referenced in the fonts section of the manifest.

packages/flutter_tools/lib/src/runner/local_engine.dart

@@ -150,6 +150,11 @@ class LocalEngineLocator {
   // Determine the host engine directory associated with the local engine:
   // Strip '_sim_' since there are no host simulator builds.
   String _getHostEngineBasename(String localEngineBasename) {
+    if (localEngineBasename.startsWith('web_') || localEngineBasename.startsWith('wasm_')) {
+      // Don't modify the web local engine's basename.
+      return localEngineBasename;
+    }
+
     String tmpBasename = localEngineBasename.replaceFirst('_sim_', '_');
     tmpBasename = tmpBasename.substring(tmpBasename.indexOf('_') + 1);
     // Strip suffix for various archs.

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

@@ -273,6 +273,13 @@ void main() {
           .childDirectory('ios-arm64_armv7')
           .childDirectory('Flutter.framework')
           .createSync(recursive: true);
+      fileSystem
+          .directory('out')
+          .childDirectory('host_debug_unopt')
+          .childDirectory('dart-sdk')
+          .childDirectory('bin')
+          .createSync(recursive: true);
+
       expect(
         artifacts.getArtifactPath(
           Artifact.flutterFramework,
@@ -325,6 +332,75 @@ void main() {
       );
     });
 
+    testWithoutContext('falls back to prebuilt dart sdk', () {
+      final String failureMessage = 'Unable to find a built dart sdk at:'
+          ' "${fileSystem.path.join('/out', 'host_debug_unopt', 'dart-sdk')}"'
+          ' or a prebuilt dart sdk at:'
+          ' "${fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk')}"';
+
+      expect(
+        () => artifacts.getArtifactPath(Artifact.frontendServerSnapshotForEngineDartSdk),
+        throwsToolExit(message: failureMessage),
+      );
+      expect(
+        () => artifacts.getHostArtifact(HostArtifact.engineDartSdkPath),
+        throwsToolExit(message: failureMessage),
+      );
+      expect(
+        () => artifacts.getHostArtifact(HostArtifact.engineDartBinary),
+        throwsToolExit(message: failureMessage),
+      );
+      expect(
+        () => artifacts.getHostArtifact(HostArtifact.dart2jsSnapshot),
+        throwsToolExit(message: failureMessage),
+      );
+      expect(
+        () => artifacts.getHostArtifact(HostArtifact.dartdevcSnapshot),
+        throwsToolExit(message: failureMessage),
+      );
+      expect(
+        () => artifacts.getHostArtifact(HostArtifact.kernelWorkerSnapshot),
+        throwsToolExit(message: failureMessage),
+      );
+
+      fileSystem
+          .directory('flutter')
+          .childDirectory('prebuilts')
+          .childDirectory('linux-x64')
+          .childDirectory('dart-sdk')
+          .childDirectory('bin')
+          .createSync(recursive: true);
+
+      expect(
+        artifacts.getArtifactPath(Artifact.frontendServerSnapshotForEngineDartSdk),
+        fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk', 'bin',
+          'snapshots', 'frontend_server.dart.snapshot'),
+      );
+      expect(
+        artifacts.getHostArtifact(HostArtifact.engineDartSdkPath).path,
+        fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk'),
+      );
+      expect(
+        artifacts.getHostArtifact(HostArtifact.engineDartBinary).path,
+        fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk', 'bin', 'dart'),
+      );
+      expect(
+        artifacts.getHostArtifact(HostArtifact.dart2jsSnapshot).path,
+        fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk',
+            'bin', 'snapshots', 'dart2js.dart.snapshot'),
+      );
+      expect(
+        artifacts.getHostArtifact(HostArtifact.dartdevcSnapshot).path,
+        fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk',
+            'bin', 'snapshots', 'dartdevc.dart.snapshot'),
+      );
+      expect(
+        artifacts.getHostArtifact(HostArtifact.kernelWorkerSnapshot).path,
+        fileSystem.path.join('/flutter', 'prebuilts', 'linux-x64', 'dart-sdk',
+            'bin', 'snapshots', 'kernel_worker.dart.snapshot'),
+      );
+    });
+
     testWithoutContext('getEngineType', () {
       expect(
         artifacts.getEngineType(TargetPlatform.android_arm, BuildMode.debug),
@@ -351,11 +427,81 @@ void main() {
         operatingSystemUtils: FakeOperatingSystemUtils(),
       );
 
-      expect(artifacts.getHostArtifact(HostArtifact.engineDartBinary).path, contains('.exe'));
+      fileSystem
+          .directory('out')
+          .childDirectory('host_debug_unopt')
+          .childDirectory('dart-sdk')
+          .childDirectory('bin')
+          .createSync(recursive: true);
+
+      expect(
+        artifacts.getHostArtifact(HostArtifact.engineDartBinary).path,
+        fileSystem.path.join('/out', 'host_debug_unopt', 'dart-sdk', 'bin', 'dart.exe'),
+      );
     });
 
     testWithoutContext('Looks up dart on linux platforms', () async {
-      expect(artifacts.getHostArtifact(HostArtifact.engineDartBinary).path, isNot(contains('.exe')));
+      fileSystem
+          .directory('/out')
+          .childDirectory('host_debug_unopt')
+          .childDirectory('dart-sdk')
+          .childDirectory('bin')
+          .createSync(recursive: true);
+
+      expect(
+        artifacts.getHostArtifact(HostArtifact.engineDartBinary).path,
+        fileSystem.path.join('/out', 'host_debug_unopt', 'dart-sdk', 'bin', 'dart'),
+      );
+    });
+
+    testWithoutContext('Finds dart-sdk in windows prebuilts', () async {
+      artifacts = LocalEngineArtifacts(
+        fileSystem.path.join(fileSystem.currentDirectory.path, 'out', 'android_debug_unopt'),
+        fileSystem.path.join(fileSystem.currentDirectory.path, 'out', 'host_debug_unopt'),
+        cache: cache,
+        fileSystem: fileSystem,
+        platform: FakePlatform(operatingSystem: 'windows'),
+        processManager: FakeProcessManager.any(),
+        operatingSystemUtils: FakeOperatingSystemUtils(),
+      );
+
+      fileSystem
+          .directory('/flutter')
+          .childDirectory('prebuilts')
+          .childDirectory('windows-x64')
+          .childDirectory('dart-sdk')
+          .childDirectory('bin')
+          .createSync(recursive: true);
+
+      expect(
+        artifacts.getHostArtifact(HostArtifact.engineDartBinary).path,
+        fileSystem.path.join('/flutter', 'prebuilts', 'windows-x64', 'dart-sdk', 'bin', 'dart.exe'),
+      );
+    });
+
+    testWithoutContext('Finds dart-sdk in macos prebuilts', () async {
+      artifacts = LocalEngineArtifacts(
+        fileSystem.path.join(fileSystem.currentDirectory.path, 'out', 'android_debug_unopt'),
+        fileSystem.path.join(fileSystem.currentDirectory.path, 'out', 'host_debug_unopt'),
+        cache: cache,
+        fileSystem: fileSystem,
+        platform: FakePlatform(operatingSystem: 'macos'),
+        processManager: FakeProcessManager.any(),
+        operatingSystemUtils: FakeOperatingSystemUtils(),
+      );
+
+      fileSystem
+          .directory('/flutter')
+          .childDirectory('prebuilts')
+          .childDirectory('macos-x64')
+          .childDirectory('dart-sdk')
+          .childDirectory('bin')
+          .createSync(recursive: true);
+
+      expect(
+        artifacts.getHostArtifact(HostArtifact.engineDartBinary).path,
+        fileSystem.path.join('/flutter', 'prebuilts', 'macos-x64', 'dart-sdk', 'bin', 'dart'),
+      );
     });
   });
 }

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

@@ -9,6 +9,7 @@ import 'package:flutter_tools/src/artifacts.dart';
 import 'package:flutter_tools/src/asset.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
+import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/bundle_builder.dart';
 import 'package:flutter_tools/src/devfs.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
@@ -457,6 +458,82 @@ flutter:
         ),
       ]),
     });
+
+    testUsingContext('Included shaders are not compiled for the web', () async {
+      fileSystem.file('.packages').createSync();
+      fileSystem.file('pubspec.yaml')
+        ..createSync()
+        ..writeAsStringSync(r'''
+  name: example
+  flutter:
+    shaders:
+      - assets/shader.frag
+  ''');
+      final AssetBundle bundle = AssetBundleFactory.instance.createBundle();
+
+      expect(await bundle.build(packagesPath: '.packages', targetPlatform: TargetPlatform.web_javascript), 0);
+
+      await writeBundle(
+        output,
+        bundle.entries,
+        bundle.entryKinds,
+        loggerOverride: testLogger,
+      );
+
+    }, overrides: <Type, Generator>{
+      Artifacts: () => artifacts,
+      FileSystem: () => fileSystem,
+      ProcessManager: () => FakeProcessManager.list(<FakeCommand>[
+        // No impeller commands are expected here because shader compilation is
+        // not supposed to happen for the web.
+      ]),
+    });
+
+    testUsingContext('Material shaders are not compiled for the web', () async {
+      fileSystem.file('.packages').createSync();
+
+      final String materialIconsPath = fileSystem.path.join(
+        getFlutterRoot(),
+        'bin', 'cache', 'artifacts', 'material_fonts',
+        'MaterialIcons-Regular.otf',
+      );
+      fileSystem.file(materialIconsPath).createSync(recursive: true);
+
+      final String materialPath = fileSystem.path.join(
+        getFlutterRoot(),
+        'packages', 'flutter', 'lib', 'src', 'material',
+      );
+      final Directory materialDir = fileSystem.directory(materialPath)..createSync(recursive: true);
+      for (final String shader in kMaterialShaders) {
+        materialDir.childFile(shader).createSync(recursive: true);
+      }
+
+      fileSystem.file('pubspec.yaml')
+        ..createSync()
+        ..writeAsStringSync(r'''
+  name: example
+  flutter:
+    uses-material-design: true
+  ''');
+      final AssetBundle bundle = AssetBundleFactory.instance.createBundle();
+
+      expect(await bundle.build(packagesPath: '.packages', targetPlatform: TargetPlatform.web_javascript), 0);
+
+      await writeBundle(
+        output,
+        bundle.entries,
+        bundle.entryKinds,
+        loggerOverride: testLogger,
+      );
+
+    }, overrides: <Type, Generator>{
+      Artifacts: () => artifacts,
+      FileSystem: () => fileSystem,
+      ProcessManager: () => FakeProcessManager.list(<FakeCommand>[
+        // No impeller commands are expected here because shader compilation is
+        // not supposed to happen for the web.
+      ]),
+    });
   });
 
   testUsingContext('Does not insert dummy file into additionalDependencies '

packages/flutter_tools/test/general.shard/runner/local_engine_test.dart

@@ -216,6 +216,52 @@ void main() {
       contains('Unable to detect local Flutter engine src directory'),
     );
   });
+
+  testWithoutContext('works for local web engine', () async {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+    final Directory localWasmEngine = fileSystem
+        .directory('$kArbitraryEngineRoot/src/out/wasm_whatever/')
+      ..createSync(recursive: true);
+    final Directory localWebEngine = fileSystem
+        .directory('$kArbitraryEngineRoot/src/out/web_whatever/')
+      ..createSync(recursive: true);
+
+    final BufferLogger wasmLogger = BufferLogger.test();
+    final LocalEngineLocator localWasmEngineLocator = LocalEngineLocator(
+      fileSystem: fileSystem,
+      flutterRoot: 'flutter/flutter',
+      logger: wasmLogger,
+      userMessages: UserMessages(),
+      platform: FakePlatform(environment: <String, String>{}),
+    );
+
+    expect(
+      await localWasmEngineLocator.findEnginePath(null, localWasmEngine.path, null),
+      matchesEngineBuildPaths(
+        hostEngine: '/arbitrary/engine/src/out/wasm_whatever',
+        targetEngine: '/arbitrary/engine/src/out/wasm_whatever',
+      ),
+    );
+    expect(wasmLogger.traceText, contains('Local engine source at /arbitrary/engine/src'));
+
+    final BufferLogger webLogger = BufferLogger.test();
+    final LocalEngineLocator localWebEngineLocator = LocalEngineLocator(
+      fileSystem: fileSystem,
+      flutterRoot: 'flutter/flutter',
+      logger: webLogger,
+      userMessages: UserMessages(),
+      platform: FakePlatform(environment: <String, String>{}),
+    );
+
+    expect(
+      await localWebEngineLocator.findEnginePath(null, localWebEngine.path, null),
+      matchesEngineBuildPaths(
+        hostEngine: '/arbitrary/engine/src/out/web_whatever',
+        targetEngine: '/arbitrary/engine/src/out/web_whatever',
+      ),
+    );
+    expect(webLogger.traceText, contains('Local engine source at /arbitrary/engine/src'));
+  });
 }
 
 Matcher matchesEngineBuildPaths({