[flutter_tools] remove SkSL bundling and dump skp on compilation. (#162849)

SkSL precompilation was only ever beneficial for iOS. For other
platforms, we recommended against it as Skia generated shaders per
target architecture which could be invalid on other devices. It is no
longer possible to use Skia on iOS.

Delete all Skia shader bundling logic.

Fixes flutter/flutter#80091

Author: Jonah Williams

packages/flutter_tools/bin/macos_assemble.sh

@@ -168,9 +168,6 @@ BuildApp() {
   if [[ -n "$PERFORMANCE_MEASUREMENT_FILE" ]]; then
     flutter_args+=("--performance-measurement-file=${PERFORMANCE_MEASUREMENT_FILE}")
   fi
-  if [[ -n "$BUNDLE_SKSL_PATH" ]]; then
-    flutter_args+=("-dBundleSkSLPath=${BUNDLE_SKSL_PATH}")
-  fi
   if [[ -n "$CODE_SIZE_DIRECTORY" ]]; then
     flutter_args+=("-dCodeSizeDirectory=${CODE_SIZE_DIRECTORY}")
   fi

packages/flutter_tools/bin/tool_backend.dart

@@ -25,7 +25,6 @@ Future<void> main(List<String> arguments) async {
   final String? localEngineHost = Platform.environment['LOCAL_ENGINE_HOST'];
   final String? projectDirectory = Platform.environment['PROJECT_DIR'];
   final String? splitDebugInfo = Platform.environment['SPLIT_DEBUG_INFO'];
-  final String? bundleSkSLPath = Platform.environment['BUNDLE_SKSL_PATH'];
   final bool trackWidgetCreation = Platform.environment['TRACK_WIDGET_CREATION'] == 'true';
   final bool treeShakeIcons = Platform.environment['TREE_SHAKE_ICONS'] == 'true';
   final bool verbose = Platform.environment['VERBOSE_SCRIPT_LOGGING'] == 'true';
@@ -94,7 +93,6 @@ or
     '-dTargetFile=$flutterTarget',
     '-dTreeShakeIcons="$treeShakeIcons"',
     '-dDartObfuscation=$dartObfuscation',
-    if (bundleSkSLPath != null) '-dBundleSkSLPath=$bundleSkSLPath',
     if (codeSizeDirectory != null) '-dCodeSizeDirectory=$codeSizeDirectory',
     if (splitDebugInfo != null) '-dSplitDebugInfo=$splitDebugInfo',
     if (dartDefines != null) '--DartDefines=$dartDefines',

packages/flutter_tools/bin/xcode_backend.dart

@@ -475,10 +475,6 @@ class Context {
       flutterArgs.add('-dCodesignIdentity=$expandedCodeSignIdentity');
     }
 
-    if (environment['BUNDLE_SKSL_PATH'] != null && environment['BUNDLE_SKSL_PATH']!.isNotEmpty) {
-      flutterArgs.add('-dBundleSkSLPath=${environment['BUNDLE_SKSL_PATH']}');
-    }
-
     if (environment['CODE_SIZE_DIRECTORY'] != null &&
         environment['CODE_SIZE_DIRECTORY']!.isNotEmpty) {
       flutterArgs.add('-dCodeSizeDirectory=${environment['CODE_SIZE_DIRECTORY']}');

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

@@ -1220,11 +1220,6 @@ class FlutterPlugin implements Plugin<Project> {
         if (project.hasProperty(propDartDefines)) {
             dartDefinesValue = project.property(propDartDefines)
         }
-        String bundleSkSLPathValue
-        final String propBundleSkslPath = "bundle-sksl-path"
-        if (project.hasProperty(propBundleSkslPath)) {
-            bundleSkSLPathValue = project.property(propBundleSkslPath)
-        }
         String performanceMeasurementFileValue
         final String propPerformanceMeasurementFile = "performance-measurement-file"
         if (project.hasProperty(propPerformanceMeasurementFile)) {
@@ -1316,7 +1311,6 @@ class FlutterPlugin implements Plugin<Project> {
                 treeShakeIcons(treeShakeIconsOptionsValue)
                 dartObfuscation(dartObfuscationValue)
                 dartDefines(dartDefinesValue)
-                bundleSkSLPath(bundleSkSLPathValue)
                 performanceMeasurementFile(performanceMeasurementFileValue)
                 codeSizeDirectory(codeSizeDirectoryValue)
                 deferredComponents(deferredComponentsValue)
@@ -1647,9 +1641,6 @@ abstract class BaseFlutterTask extends DefaultTask {
     @Optional @Input
     String dartDefines
 
-    @Optional @Input
-    String bundleSkSLPath
-
     @Optional @Input
     String codeSizeDirectory
 
@@ -1740,9 +1731,6 @@ abstract class BaseFlutterTask extends DefaultTask {
             if (dartDefines != null) {
                 args("--DartDefines=${dartDefines}")
             }
-            if (bundleSkSLPath != null) {
-                args("-dBundleSkSLPath=${bundleSkSLPath}")
-            }
             if (codeSizeDirectory != null) {
                 args("-dCodeSizeDirectory=${codeSizeDirectory}")
             }

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

@@ -653,12 +653,6 @@ class AndroidDevice extends Device {
       if (debuggingOptions.traceSystrace) ...<String>['--ez', 'trace-systrace', 'true'],
       if (traceToFile != null) ...<String>['--es', 'trace-to-file', traceToFile],
       if (debuggingOptions.endlessTraceBuffer) ...<String>['--ez', 'endless-trace-buffer', 'true'],
-      if (debuggingOptions.dumpSkpOnShaderCompilation) ...<String>[
-        '--ez',
-        'dump-skp-on-shader-compilation',
-        'true',
-      ],
-      if (debuggingOptions.cacheSkSL) ...<String>['--ez', 'cache-sksl', 'true'],
       if (debuggingOptions.purgePersistentCache) ...<String>[
         '--ez',
         'purge-persistent-cache',

packages/flutter_tools/lib/src/base/command_help.dart

@@ -47,11 +47,6 @@ class CommandHelp {
     'debugDumpLayerTree',
   );
 
-  late final CommandHelpOption M = _makeOption(
-    'M',
-    'Write SkSL shaders to a unique file in the project directory.',
-  );
-
   late final CommandHelpOption P = _makeOption(
     'P',
     'Toggle performance overlay.',

packages/flutter_tools/lib/src/build_info.dart

@@ -35,7 +35,6 @@ class BuildInfo {
     this.splitDebugInfoPath,
     this.dartObfuscation = false,
     List<String>? dartDefines,
-    this.bundleSkSLPath,
     List<String>? dartExperiments,
     required this.treeShakeIcons,
     this.performanceMeasurementFile,
@@ -118,11 +117,6 @@ class BuildInfo {
   /// Whether to apply dart source code obfuscation.
   final bool dartObfuscation;
 
-  /// An optional path to a JSON containing object SkSL shaders.
-  ///
-  /// Currently this is only supported for Android builds.
-  final String? bundleSkSLPath;
-
   /// Additional constant values to be made available in the Dart program.
   ///
   /// These values can be used with the const `fromEnvironment` constructors of
@@ -294,7 +288,6 @@ class BuildInfo {
       if (splitDebugInfoPath != null) kSplitDebugInfo: splitDebugInfoPath!,
       kTrackWidgetCreation: trackWidgetCreation.toString(),
       kIconTreeShakerFlag: treeShakeIcons.toString(),
-      if (bundleSkSLPath != null) kBundleSkSLPath: bundleSkSLPath!,
       if (codeSizeDirectory != null) kCodeSizeDirectory: codeSizeDirectory!,
       if (fileSystemRoots.isNotEmpty) kFileSystemRoots: fileSystemRoots.join(','),
       if (fileSystemScheme != null) kFileSystemScheme: fileSystemScheme!,
@@ -323,7 +316,6 @@ class BuildInfo {
       'TREE_SHAKE_ICONS': treeShakeIcons.toString(),
       if (performanceMeasurementFile != null)
         'PERFORMANCE_MEASUREMENT_FILE': performanceMeasurementFile!,
-      if (bundleSkSLPath != null) 'BUNDLE_SKSL_PATH': bundleSkSLPath!,
       'PACKAGE_CONFIG': packageConfigPath,
       if (codeSizeDirectory != null) 'CODE_SIZE_DIRECTORY': codeSizeDirectory!,
       if (flavor != null) 'FLAVOR': flavor!,
@@ -348,7 +340,6 @@ class BuildInfo {
       '-Ptree-shake-icons=$treeShakeIcons',
       if (performanceMeasurementFile != null)
         '-Pperformance-measurement-file=$performanceMeasurementFile',
-      if (bundleSkSLPath != null) '-Pbundle-sksl-path=$bundleSkSLPath',
       if (codeSizeDirectory != null) '-Pcode-size-directory=$codeSizeDirectory',
       for (final String projectArg in androidProjectArgs) '-P$projectArg',
     ];
@@ -975,9 +966,6 @@ const String kIconTreeShakerFlag = 'TreeShakeIcons';
 /// Controls whether a web build should use local canvaskit or the CDN
 const String kUseLocalCanvasKitFlag = 'UseLocalCanvasKit';
 
-/// The input key for an SkSL bundle path.
-const String kBundleSkSLPath = 'BundleSkSLPath';
-
 /// The define to pass build name
 const String kBuildName = 'BuildName';
 

packages/flutter_tools/lib/src/build_system/targets/assets.dart

@@ -8,9 +8,7 @@ import '../../artifacts.dart';
 import '../../asset.dart';
 import '../../base/common.dart';
 import '../../base/file_system.dart';
-import '../../base/logger.dart';
 import '../../build_info.dart';
-import '../../convert.dart';
 import '../../dart/package_map.dart';
 import '../../devfs.dart';
 import '../../flutter_manifest.dart';
@@ -42,17 +40,6 @@ Future<Depfile> copyAssets(
   List<File> additionalInputs = const <File>[],
   String? flavor,
 }) async {
-  // Check for an SkSL bundle.
-  final String? shaderBundlePath =
-      environment.defines[kBundleSkSLPath] ?? environment.inputs[kBundleSkSLPath];
-  final DevFSContent? skslBundle = processSkSLBundle(
-    shaderBundlePath,
-    engineVersion: environment.engineVersion,
-    fileSystem: environment.fileSystem,
-    logger: environment.logger,
-    targetPlatform: targetPlatform,
-  );
-
   final File pubspecFile = environment.projectDir.childFile('pubspec.yaml');
   // Only the default asset bundle style is supported in assemble.
   final AssetBundle assetBundle =
@@ -121,12 +108,6 @@ Future<Depfile> copyAssets(
         ),
       );
     }),
-    if (skslBundle != null)
-      kSkSLShaderBundlePath: AssetBundleEntry(
-        skslBundle,
-        kind: AssetKind.regular,
-        transformers: const <AssetTransformerEntry>[],
-      ),
   };
 
   await Future.wait<void>(
@@ -262,85 +243,9 @@ Future<Depfile> copyAssets(
     );
   }
   final Depfile depfile = Depfile(inputs + assetBundle.additionalDependencies, outputs);
-  if (shaderBundlePath != null) {
-    final File skSLBundleFile = environment.fileSystem.file(shaderBundlePath).absolute;
-    depfile.inputs.add(skSLBundleFile);
-  }
   return depfile;
 }
 
-/// The path of the SkSL JSON bundle included in flutter_assets.
-const String kSkSLShaderBundlePath = 'io.flutter.shaders.json';
-
-/// Validate and process an SkSL asset bundle in a [DevFSContent].
-///
-/// Returns `null` if the bundle was not provided, otherwise attempts to
-/// validate the bundle.
-///
-/// Throws [Exception] if the bundle is invalid due to formatting issues.
-///
-/// If the current target platform is different than the platform constructed
-/// for the bundle, a warning will be printed.
-DevFSContent? processSkSLBundle(
-  String? bundlePath, {
-  required TargetPlatform targetPlatform,
-  required FileSystem fileSystem,
-  required Logger logger,
-  String? engineVersion,
-}) {
-  if (bundlePath == null) {
-    return null;
-  }
-  // Step 1: check that file exists.
-  final File skSLBundleFile = fileSystem.file(bundlePath);
-  if (!skSLBundleFile.existsSync()) {
-    logger.printError('$bundlePath does not exist.');
-    throw Exception('SkSL bundle was invalid.');
-  }
-
-  // Step 2: validate top level bundle structure.
-  Map<String, Object?>? bundle;
-  try {
-    final Object? rawBundle = json.decode(skSLBundleFile.readAsStringSync());
-    if (rawBundle is Map<String, Object?>) {
-      bundle = rawBundle;
-    } else {
-      logger.printError('"$bundle" was not a JSON object: $rawBundle');
-      throw Exception('SkSL bundle was invalid.');
-    }
-  } on FormatException catch (err) {
-    logger.printError('"$bundle" was not a JSON object: $err');
-    throw Exception('SkSL bundle was invalid.');
-  }
-  // Step 3: Validate that:
-  // * The engine revision the bundle was compiled with
-  //   is the same as the current revision.
-  // * The target platform is the same (this one is a warning only).
-  final String? bundleEngineRevision = bundle['engineRevision'] as String?;
-  if (bundleEngineRevision != engineVersion) {
-    logger.printError(
-      'Expected Flutter $bundleEngineRevision, but found $engineVersion\n'
-      'The SkSL bundle was produced with a different engine version. It must '
-      'be recreated for the current Flutter version.',
-    );
-    throw Exception('SkSL bundle was invalid');
-  }
-
-  final TargetPlatform? bundlePlatform = switch (bundle['platform'] as String?) {
-    final String platform => getTargetPlatformForName(platform),
-    null => null,
-  };
-
-  if (bundlePlatform != targetPlatform) {
-    logger.printError(
-      'The SkSL bundle was created for $bundlePlatform, but the current '
-      'platform is $targetPlatform. This may lead to less efficient shader '
-      'caching.',
-    );
-  }
-  return DevFSStringContent(json.encode(<String, Object?>{'data': bundle['data']}));
-}
-
 /// Copy the assets defined in the flutter manifest into a build directory.
 class CopyAssets extends Target {
   const CopyAssets();

packages/flutter_tools/lib/src/commands/build_apk.dart

@@ -29,7 +29,6 @@ class BuildApkCommand extends BuildSubCommand {
     addDartObfuscationOption();
     usesDartDefineOption();
     usesExtraDartFlagOptions(verboseHelp: verboseHelp);
-    addBundleSkSLPathOption(hide: !verboseHelp);
     addEnableExperimentation(hide: !verboseHelp);
     addBuildPerformanceFile(hide: !verboseHelp);
     addNullSafetyModeOptions(hide: !verboseHelp);

packages/flutter_tools/lib/src/commands/build_appbundle.dart

@@ -32,7 +32,6 @@ class BuildAppBundleCommand extends BuildSubCommand {
     addDartObfuscationOption();
     usesDartDefineOption();
     usesExtraDartFlagOptions(verboseHelp: verboseHelp);
-    addBundleSkSLPathOption(hide: !verboseHelp);
     addBuildPerformanceFile(hide: !verboseHelp);
     usesTrackWidgetCreation(verboseHelp: verboseHelp);
     addNullSafetyModeOptions(hide: !verboseHelp);