[flutter_tools] hide usage of package:mustache behind interface (#51500)

packages/flutter_tools/lib/executable.dart

@@ -6,13 +6,14 @@ import 'dart:async';
 
 import 'runner.dart' as runner;
 import 'src/base/context.dart';
+import 'src/base/template.dart';
 // The build_runner code generation is provided here to make it easier to
 // avoid introducing the dependency into google3. Not all build* packages
 // are synced internally.
 import 'src/build_runner/build_runner.dart';
+import 'src/build_runner/mustache_template.dart';
 import 'src/build_runner/resident_web_runner.dart';
 import 'src/build_runner/web_compilation_delegate.dart';
-
 import 'src/codegen.dart';
 import 'src/commands/analyze.dart';
 import 'src/commands/assemble.dart';
@@ -110,8 +111,10 @@ Future<void> main(List<String> args) async {
        // the build runner packages are not synced internally.
        CodeGenerator: () => const BuildRunner(),
        WebCompilationProxy: () => BuildRunnerWebCompilationProxy(),
-       // The web runner is not supported internally because it depends
+       // The web runner is not supported in google3 because it depends
        // on dwds.
        WebRunnerFactory: () => DwdsWebRunnerFactory(),
+       // The mustache dependency is different in google3
+       TemplateRenderer: () => const MustacheTemplateRenderer(),
      });
 }

packages/flutter_tools/lib/src/base/template.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.
+
+/// An indirection around our mustache templating system to avoid a
+/// dependency on mustache..
+abstract class TemplateRenderer {
+  const TemplateRenderer();
+
+  String renderString(String template, dynamic context, {bool htmlEscapeValues = false});
+}

packages/flutter_tools/lib/src/build_runner/mustache_template.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 'package:mustache/mustache.dart';
+
+import '../base/template.dart';
+
+/// An indirection around mustache use to allow google3 to use a different dependency.
+class MustacheTemplateRenderer extends TemplateRenderer {
+  const MustacheTemplateRenderer();
+
+  @override
+  String renderString(String template, dynamic context, {bool htmlEscapeValues = false}) {
+    return Template(template, htmlEscapeValues: htmlEscapeValues).renderString(context);
+  }
+}

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

@@ -8,8 +8,6 @@ import '../../asset.dart';
 import '../../base/file_system.dart';
 import '../../devfs.dart';
 import '../../globals.dart' as globals;
-import '../../plugins.dart';
-import '../../project.dart';
 import '../build_system.dart';
 import '../depfile.dart';
 import 'dart.dart';
@@ -119,45 +117,3 @@ class CopyAssets extends Target {
     );
   }
 }
-
-/// Rewrites the `.flutter-plugins` file of [project] based on the plugin
-/// dependencies declared in `pubspec.yaml`.
-// TODO(jonahwiliams): this should be per platform and located in build
-// outputs.
-class FlutterPlugins extends Target {
-  const FlutterPlugins();
-
-  @override
-  String get name => 'flutter_plugins';
-
-  @override
-  List<Target> get dependencies => const <Target>[];
-
-  @override
-  List<Source> get inputs => const <Source>[
-    Source.pattern('{FLUTTER_ROOT}/packages/flutter_tools/lib/src/build_system/targets/assets.dart'),
-    Source.pattern('{PROJECT_DIR}/pubspec.yaml'),
-  ];
-
-  @override
-  List<Source> get outputs => const <Source>[
-    Source.pattern('{PROJECT_DIR}/.flutter-plugins'),
-  ];
-
-  @override
-  Future<void> build(Environment environment) async {
-    // The pubspec may change for reasons other than plugins changing, so we compare
-    // the manifest before writing. Some hosting build systems use timestamps
-    // so we need to be careful to avoid tricking them into doing more work than
-    // necessary.
-    final FlutterProject project = FlutterProject.fromDirectory(environment.projectDir);
-    final List<Plugin> plugins = findPlugins(project);
-    final String pluginManifest = plugins
-      .map<String>((Plugin p) => '${p.name}=${globals.fsUtils.escapePath(p.path)}')
-      .join('\n');
-    final File flutterPluginsFile = environment.projectDir.childFile('.flutter-plugins');
-    if (!flutterPluginsFile.existsSync() || flutterPluginsFile.readAsStringSync() != pluginManifest) {
-      flutterPluginsFile.writeAsStringSync(pluginManifest);
-    }
-  }
-}

packages/flutter_tools/lib/src/globals.dart

@@ -17,6 +17,7 @@ import 'base/io.dart';
 import 'base/logger.dart';
 import 'base/net.dart';
 import 'base/os.dart';
+import 'base/template.dart';
 import 'base/terminal.dart';
 import 'base/user_messages.dart';
 import 'cache.dart';
@@ -160,3 +161,6 @@ PlistParser _defaultInstance;
 
 /// The [ChromeLauncher] instance.
 ChromeLauncher get chromeLauncher => context.get<ChromeLauncher>();
+
+/// The global template renderer
+TemplateRenderer get templateRenderer => context.get<TemplateRenderer>();

packages/flutter_tools/lib/src/plugins.dart

@@ -5,7 +5,6 @@
 import 'dart:async';
 
 import 'package:meta/meta.dart';
-import 'package:mustache/mustache.dart' as mustache;
 import 'package:yaml/yaml.dart';
 
 import 'android/gradle.dart';
@@ -23,8 +22,8 @@ import 'windows/property_sheet.dart';
 import 'windows/visual_studio_solution_utils.dart';
 
 void _renderTemplateToFile(String template, dynamic context, String filePath) {
-  final String renderedTemplate =
-     mustache.Template(template, htmlEscapeValues: false).renderString(context);
+  final String renderedTemplate = globals.templateRenderer
+    .renderString(template, context, htmlEscapeValues: false);
   final File file = globals.fs.file(filePath);
   file.createSync(recursive: true);
   file.writeAsStringSync(renderedTemplate);

packages/flutter_tools/lib/src/template.dart

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:mustache/mustache.dart' as mustache;
-
 import 'base/common.dart';
 import 'base/file_system.dart';
 import 'cache.dart';
@@ -182,7 +180,7 @@ class Template {
 
       if (sourceFile.path.endsWith(templateExtension)) {
         final String templateContents = sourceFile.readAsStringSync();
-        final String renderedContents = mustache.Template(templateContents).renderString(context);
+        final String renderedContents = globals.templateRenderer.renderString(templateContents, context);
 
         finalDestinationFile.writeAsStringSync(renderedContents);
 

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

@@ -90,18 +90,4 @@ flutter:
     ProcessManager: () => FakeProcessManager.any(),
     Platform: () => platform,
   });
-
-  testUsingContext('FlutterPlugins updates required files as needed', () async {
-    fileSystem.file('pubspec.yaml')
-      ..writeAsStringSync('name: foo\ndependencies:\n  foo: any\n');
-
-    await const FlutterPlugins().build(Environment.test(
-      fileSystem.currentDirectory,
-    ));
-
-    expect(fileSystem.file('.flutter-plugins'), exists);
-  }, overrides: <Type, Generator>{
-    FileSystem: () => fileSystem,
-    ProcessManager: () => FakeProcessManager.any(),
-  });
 }

packages/flutter_tools/test/src/context.dart

@@ -14,8 +14,10 @@ import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/os.dart';
 import 'package:flutter_tools/src/base/process.dart';
 import 'package:flutter_tools/src/base/signals.dart';
+import 'package:flutter_tools/src/base/template.dart';
 import 'package:flutter_tools/src/base/terminal.dart';
 import 'package:flutter_tools/src/base/time.dart';
+import 'package:flutter_tools/src/build_runner/mustache_template.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/context_runner.dart';
 import 'package:flutter_tools/src/dart/pub.dart';
@@ -129,6 +131,7 @@ void testUsingContext(
           Signals: () => FakeSignals(),
           Pub: () => ThrowingPub(), // prevent accidentally using pub.
           GitHubTemplateCreator: () => MockGitHubTemplateCreator(),
+          TemplateRenderer: () => const MustacheTemplateRenderer(),
         },
         body: () {
           final String flutterRoot = getFlutterRoot();