Consume flutter.js from the engine artifacts. (#137113)

Work in progress... currently testing against presubmit.

packages/flutter_tools/lib/src/artifacts.dart

@@ -81,6 +81,9 @@ enum HostArtifact {
   /// The libraries JSON file for web release builds.
   flutterWebLibrariesJson,
 
+  // The flutter.js bootstrapping file provided by the engine.
+  flutterJsDirectory,
+
   /// Folder that contains platform dill files for the web sdk.
   webPlatformKernelFolder,
 
@@ -232,6 +235,8 @@ String _hostArtifactToFileName(HostArtifact artifact, Platform platform) {
   switch (artifact) {
     case HostArtifact.flutterWebSdk:
       return '';
+    case HostArtifact.flutterJsDirectory:
+      return 'flutter_js';
     case HostArtifact.iosDeploy:
       return 'ios-deploy';
     case HostArtifact.idevicesyslog:
@@ -440,6 +445,9 @@ class CachedArtifacts implements Artifacts {
       case HostArtifact.flutterWebLibrariesJson:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
+      case HostArtifact.flutterJsDirectory:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'flutter_js');
+        return _fileSystem.directory(path);
       case HostArtifact.webPlatformKernelFolder:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel');
         return _fileSystem.file(path);
@@ -893,6 +901,9 @@ class CachedLocalEngineArtifacts implements Artifacts {
       case HostArtifact.flutterWebLibrariesJson:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
+      case HostArtifact.flutterJsDirectory:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'flutter_js');
+        return _fileSystem.directory(path);
       case HostArtifact.webPlatformKernelFolder:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel');
         return _fileSystem.file(path);
@@ -1205,6 +1216,9 @@ class CachedLocalWebSdkArtifacts implements Artifacts {
       case HostArtifact.flutterWebLibrariesJson:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), _hostArtifactToFileName(artifact, _platform));
         return _fileSystem.file(path);
+      case HostArtifact.flutterJsDirectory:
+        final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'flutter_js');
+        return _fileSystem.directory(path);
       case HostArtifact.webPlatformKernelFolder:
         final String path = _fileSystem.path.join(_getFlutterWebSdkPath(), 'kernel');
         return _fileSystem.file(path);

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

@@ -20,7 +20,6 @@ import '../../globals.dart' as globals;
 import '../../html_utils.dart';
 import '../../project.dart';
 import '../../web/compile.dart';
-import '../../web/file_generators/flutter_js.dart' as flutter_js;
 import '../../web/file_generators/flutter_service_worker_js.dart';
 import '../../web/file_generators/main_dart.dart' as main_dart;
 import '../../web/file_generators/wasm_bootstrap.dart' as wasm_bootstrap;
@@ -525,11 +524,12 @@ class WebBuiltInAssets extends Target {
     }
 
     // Write the flutter.js file
-    final File flutterJsFile = environment.outputDir.childFile('flutter.js');
-    final String fileGeneratorsPath =
-        environment.artifacts.getArtifactPath(Artifact.flutterToolsFileGenerators);
-    flutterJsFile.writeAsStringSync(
-        flutter_js.generateFlutterJsFile(fileGeneratorsPath));
+    final String flutterJsOut = fileSystem.path.join(environment.outputDir.path, 'flutter.js');
+    final File flutterJsFile = fileSystem.file(fileSystem.path.join(
+      globals.artifacts!.getHostArtifact(HostArtifact.flutterJsDirectory).path,
+      'flutter.js',
+    ));
+    flutterJsFile.copySync(flutterJsOut);
   }
 }
 

packages/flutter_tools/lib/src/isolated/devfs_web.dart

@@ -40,7 +40,6 @@ import '../vmservice.dart';
 import '../web/bootstrap.dart';
 import '../web/chrome.dart';
 import '../web/compile.dart';
-import '../web/file_generators/flutter_js.dart' as flutter_js;
 import '../web/memory_fs.dart';
 
 typedef DwdsLauncher = Future<Dwds> Function({
@@ -834,14 +833,11 @@ class WebDevFS implements DevFS {
       final String entrypoint = globals.fs.path.basename(mainFile.path);
       webAssetServer.writeBytes(entrypoint, mainFile.readAsBytesSync());
       webAssetServer.writeBytes('require.js', requireJS.readAsBytesSync());
+      webAssetServer.writeBytes('flutter.js', flutterJs.readAsBytesSync());
       webAssetServer.writeBytes(
           'stack_trace_mapper.js', stackTraceMapper.readAsBytesSync());
       webAssetServer.writeFile(
           'manifest.json', '{"info":"manifest not generated in run mode."}');
-      final String fileGeneratorsPath = globals.artifacts!
-          .getArtifactPath(Artifact.flutterToolsFileGenerators);
-      webAssetServer.writeFile(
-          'flutter.js', flutter_js.generateFlutterJsFile(fileGeneratorsPath));
       webAssetServer.writeFile('flutter_service_worker.js',
           '// Service worker not loaded in run mode.');
       webAssetServer.writeFile(
@@ -934,6 +930,12 @@ class WebDevFS implements DevFS {
     'require.js',
   ));
 
+  @visibleForTesting
+  final File flutterJs = globals.fs.file(globals.fs.path.join(
+    globals.artifacts!.getHostArtifact(HostArtifact.flutterJsDirectory).path,
+    'flutter.js',
+  ));
+
   @visibleForTesting
   final File stackTraceMapper = globals.fs.file(globals.fs.path.join(
     globals.artifacts!.getArtifactPath(Artifact.engineDartSdkPath, platform: TargetPlatform.web_javascript),

packages/flutter_tools/lib/src/web/file_generators/flutter_js.dart

-// Copyright 2014 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-import '../../globals.dart' as globals;
-
-/// Generates the flutter.js file.
-///
-/// flutter.js should be completely static, so **do not use any parameter or
-/// environment variable to generate this file**.
-String generateFlutterJsFile(String fileGeneratorsPath) {
-  final String flutterJsPath = globals.localFileSystem.path.join(
-    fileGeneratorsPath,
-    'js',
-    'flutter.js',
-  );
-  return globals.localFileSystem.file(flutterJsPath).readAsStringSync();
-}

packages/flutter_tools/test/general.shard/build_system/targets/web_test.dart

@@ -15,7 +15,6 @@ import 'package:flutter_tools/src/globals.dart' as globals;
 import 'package:flutter_tools/src/html_utils.dart';
 import 'package:flutter_tools/src/isolated/mustache_template.dart';
 import 'package:flutter_tools/src/web/compile.dart';
-import 'package:flutter_tools/src/web/file_generators/flutter_js.dart' as flutter_js;
 import 'package:flutter_tools/src/web/file_generators/flutter_service_worker_js.dart';
 
 import '../../../src/common.dart';
@@ -70,6 +69,8 @@ void main() {
         ..writeAsStringSync('foo:foo/lib/\n');
       globals.fs.currentDirectory.childDirectory('bar').createSync();
       processManager = FakeProcessManager.empty();
+      globals.fs.file('bin/cache/flutter_web_sdk/flutter_js/flutter.js')
+        .createSync(recursive: true);
 
       environment = Environment.test(
         globals.fs.currentDirectory,
@@ -1056,41 +1057,6 @@ void main() {
       contains('"main.dart.js"'));
   }));
 
-  test('flutter.js sanity checks', () => testbed.run(() {
-    final String fileGeneratorsPath = environment.artifacts
-        .getArtifactPath(Artifact.flutterToolsFileGenerators);
-    final String flutterJsContents =
-        flutter_js.generateFlutterJsFile(fileGeneratorsPath);
-    expect(flutterJsContents, contains('"use strict";'));
-    expect(flutterJsContents, contains('main.dart.js'));
-    expect(flutterJsContents, contains('if (!("serviceWorker" in navigator))'));
-    expect(flutterJsContents, contains(r'/\.js$/,'));
-    expect(flutterJsContents, contains('flutter_service_worker.js?v='));
-    expect(flutterJsContents, contains('document.createElement("script")'));
-    expect(flutterJsContents, contains('"application/javascript"'));
-    expect(flutterJsContents, contains('const baseUri = '));
-    expect(flutterJsContents, contains('document.querySelector("base")'));
-    expect(flutterJsContents, contains('.getAttribute("href")'));
-  }));
-
-  test('flutter.js is not dynamically generated', () => testbed.run(() async {
-    globals.fs.file('bin/cache/flutter_web_sdk/canvaskit/foo')
-      ..createSync(recursive: true)
-      ..writeAsStringSync('OL');
-
-    await WebBuiltInAssets(globals.fs, WebRendererMode.auto, isWasm: false).build(environment);
-
-    // No caching of source maps.
-    final String fileGeneratorsPath = environment.artifacts
-        .getArtifactPath(Artifact.flutterToolsFileGenerators);
-    final String flutterJsContents =
-        flutter_js.generateFlutterJsFile(fileGeneratorsPath);
-    expect(
-      environment.outputDir.childFile('flutter.js').readAsStringSync(),
-      equals(flutterJsContents),
-    );
-  }));
-
   test('wasm build copies and generates specific files', () => testbed.run(() async {
     globals.fs.file('bin/cache/flutter_web_sdk/canvaskit/canvaskit.wasm')
       .createSync(recursive: true);

packages/flutter_tools/test/general.shard/web/devfs_web_test.dart

@@ -685,6 +685,7 @@ void main() {
       nullSafetyMode: NullSafetyMode.unsound,
     );
     webDevFS.requireJS.createSync(recursive: true);
+    webDevFS.flutterJs.createSync(recursive: true);
     webDevFS.stackTraceMapper.createSync(recursive: true);
 
     final Uri uri = await webDevFS.create();
@@ -798,6 +799,7 @@ void main() {
       nullSafetyMode: NullSafetyMode.sound,
     );
     webDevFS.requireJS.createSync(recursive: true);
+    webDevFS.flutterJs.createSync(recursive: true);
     webDevFS.stackTraceMapper.createSync(recursive: true);
 
     final Uri uri = await webDevFS.create();

packages/flutter_tools/test/integration.shard/test_data/project.dart

@@ -3,8 +3,6 @@
 // found in the LICENSE file.
 
 import 'package:file/file.dart';
-import 'package:flutter_tools/src/artifacts.dart';
-import 'package:flutter_tools/src/web/file_generators/flutter_js.dart';
 
 import '../test_utils.dart';
 import 'deferred_components_config.dart';
@@ -60,13 +58,9 @@ abstract class Project {
     }
     deferredComponents?.setUpIn(dir);
 
-    final String fileGeneratorsPath =
-        Artifacts.test().getArtifactPath(Artifact.flutterToolsFileGenerators);
-    final String flutterJsContents = generateFlutterJsFile(fileGeneratorsPath);
-
     // Setup for different flutter web initializations
     writeFile(fileSystem.path.join(dir.path, 'web', 'index.html'), indexHtml);
-    writeFile(fileSystem.path.join(dir.path, 'web', 'flutter.js'), flutterJsContents);
+    writeFile(fileSystem.path.join(dir.path, 'web', 'flutter.js'), '');
     writeFile(fileSystem.path.join(dir.path, 'web', 'flutter_service_worker.js'), '');
     writePackages(dir.path);
     await getPackages(dir.path);