Rewire all Dart entrypoints when the Dart plugin registrant is used. (#91856)

packages/flutter_tools/lib/src/flutter_plugins.dart

@@ -685,6 +685,9 @@ const String _dartPluginRegistryForNonWebTemplate = '''
 
 // @dart = {{dartLanguageVersion}}
 
+// When `{{mainEntrypoint}}` defines `main`, that definition is shadowed by the definition below.
+export '{{mainEntrypoint}}';
+
 import '{{mainEntrypoint}}' as entrypoint;
 import 'dart:io'; // flutter_ignore: dart_io_import.
 {{#android}}

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

@@ -243,6 +243,9 @@ void main() {
           '\n'
           '// @dart = 2.12\n'
           '\n'
+          '// When `package:path_provider_example/main.dart` defines `main`, that definition is shadowed by the definition below.\n'
+          "export 'package:path_provider_example/main.dart';\n"
+          '\n'
           "import 'package:path_provider_example/main.dart' as entrypoint;\n"
           "import 'dart:io'; // flutter_ignore: dart_io_import.\n"
           "import 'package:path_provider_linux/path_provider_linux.dart';\n"
@@ -382,6 +385,9 @@ void main() {
           '\n'
           '// @dart = 2.12\n'
           '\n'
+          '// When `file:///root/external.dart` defines `main`, that definition is shadowed by the definition below.\n'
+          "export 'file:///root/external.dart';\n"
+          '\n'
           "import 'file:///root/external.dart' as entrypoint;\n"
           "import 'dart:io'; // flutter_ignore: dart_io_import.\n"
           "import 'package:path_provider_linux/path_provider_linux.dart';\n"

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

@@ -599,6 +599,9 @@ void main() {
           '\n'
           '// @dart = 2.8\n'
           '\n'
+          '// When `package:app/main.dart` defines `main`, that definition is shadowed by the definition below.\n'
+          "export 'package:app/main.dart';\n"
+          '\n'
           "import 'package:app/main.dart' as entrypoint;\n"
           "import 'dart:io'; // flutter_ignore: dart_io_import.\n"
           "import 'package:url_launcher_android/url_launcher_android.dart';\n"
@@ -699,6 +702,203 @@ void main() {
         ProcessManager: () => FakeProcessManager.any(),
       });
 
+      testUsingContext('Rewires entrypoints', () async {
+        flutterProject.isModule = true;
+
+        createFakeDartPlugins(
+          flutterProject,
+          flutterManifest,
+          fs,
+          <String, String>{
+            'url_launcher_android': '''
+  flutter:
+    plugin:
+      implements: url_launcher
+      platforms:
+        android:
+          dartPluginClass: AndroidPlugin
+''',
+          'url_launcher_ios': '''
+  flutter:
+    plugin:
+      implements: url_launcher
+      platforms:
+        ios:
+          dartPluginClass: IosPlugin
+''',
+          'url_launcher_macos': '''
+  flutter:
+    plugin:
+      implements: url_launcher
+      platforms:
+        macos:
+          dartPluginClass: MacOSPlugin
+''',
+         'url_launcher_linux': '''
+  flutter:
+    plugin:
+      implements: url_launcher
+      platforms:
+        linux:
+          dartPluginClass: LinuxPlugin
+''',
+         'url_launcher_windows': '''
+  flutter:
+    plugin:
+      implements: url_launcher
+      platforms:
+        windows:
+          dartPluginClass: WindowsPlugin
+''',
+         'awesome_macos': '''
+  flutter:
+    plugin:
+      implements: awesome
+      platforms:
+        macos:
+          dartPluginClass: AwesomeMacOS
+'''
+          });
+
+        final Directory libDir = flutterProject.directory.childDirectory('lib');
+        libDir.createSync(recursive: true);
+
+        final File mainFile = libDir.childFile('main.dart');
+        mainFile.writeAsStringSync('''
+// @dart = 2.8
+void main() {
+}
+
+@pragma('vm:entry-point')
+void dream() => run(interactive: false);
+
+@pragma('vm:entry-point', foobar)
+void dreamWithFlags() => run(interactive: false);
+''');
+        final PackageConfig packageConfig = await loadPackageConfigWithLogging(
+          flutterProject.directory.childDirectory('.dart_tool').childFile('package_config.json'),
+          logger: globals.logger,
+          throwOnError: false,
+        );
+        await generateMainDartWithPluginRegistrant(
+          flutterProject,
+          packageConfig,
+          'package:app/main.dart',
+          mainFile,
+          throwOnPluginPubspecError: true,
+        );
+        expect(flutterProject.dartPluginRegistrant.readAsStringSync(),
+          '//\n'
+          '// Generated file. Do not edit.\n'
+          '// This file is generated from template in file `flutter_tools/lib/src/flutter_plugins.dart`.\n'
+          '//\n'
+          '\n'
+          '// @dart = 2.8\n'
+          '\n'
+          '// When `package:app/main.dart` defines `main`, that definition is shadowed by the definition below.\n'
+          "export 'package:app/main.dart';\n"
+          '\n'
+          "import 'package:app/main.dart' as entrypoint;\n"
+          "import 'dart:io'; // flutter_ignore: dart_io_import.\n"
+          "import 'package:url_launcher_android/url_launcher_android.dart';\n"
+          "import 'package:url_launcher_ios/url_launcher_ios.dart';\n"
+          "import 'package:url_launcher_linux/url_launcher_linux.dart';\n"
+          "import 'package:awesome_macos/awesome_macos.dart';\n"
+          "import 'package:url_launcher_macos/url_launcher_macos.dart';\n"
+          "import 'package:url_launcher_windows/url_launcher_windows.dart';\n"
+          '\n'
+          "@pragma('vm:entry-point')\n"
+          'class _PluginRegistrant {\n'
+          '\n'
+          "  @pragma('vm:entry-point')\n"
+          '  static void register() {\n'
+          '    if (Platform.isAndroid) {\n'
+          '      try {\n'
+          '        AndroidPlugin.registerWith();\n'
+          '      } catch (err) {\n'
+          '        print(\n'
+          "          '`url_launcher_android` threw an error: \$err. '\n"
+          "          'The app may not function as expected until you remove this plugin from pubspec.yaml'\n"
+          '        );\n'
+          '        rethrow;\n'
+          '      }\n'
+          '\n'
+          '    } else if (Platform.isIOS) {\n'
+          '      try {\n'
+          '        IosPlugin.registerWith();\n'
+          '      } catch (err) {\n'
+          '        print(\n'
+          "          '`url_launcher_ios` threw an error: \$err. '\n"
+          "          'The app may not function as expected until you remove this plugin from pubspec.yaml'\n"
+          '        );\n'
+          '        rethrow;\n'
+          '      }\n'
+          '\n'
+          '    } else if (Platform.isLinux) {\n'
+          '      try {\n'
+          '        LinuxPlugin.registerWith();\n'
+          '      } catch (err) {\n'
+          '        print(\n'
+          "          '`url_launcher_linux` threw an error: \$err. '\n"
+          "          'The app may not function as expected until you remove this plugin from pubspec.yaml'\n"
+          '        );\n'
+          '        rethrow;\n'
+          '      }\n'
+          '\n'
+          '    } else if (Platform.isMacOS) {\n'
+          '      try {\n'
+          '        AwesomeMacOS.registerWith();\n'
+          '      } catch (err) {\n'
+          '        print(\n'
+          "          '`awesome_macos` threw an error: \$err. '\n"
+          "          'The app may not function as expected until you remove this plugin from pubspec.yaml'\n"
+          '        );\n'
+          '        rethrow;\n'
+          '      }\n'
+          '\n'
+          '      try {\n'
+          '        MacOSPlugin.registerWith();\n'
+          '      } catch (err) {\n'
+          '        print(\n'
+          "          '`url_launcher_macos` threw an error: \$err. '\n"
+          "          'The app may not function as expected until you remove this plugin from pubspec.yaml'\n"
+          '        );\n'
+          '        rethrow;\n'
+          '      }\n'
+          '\n'
+          '    } else if (Platform.isWindows) {\n'
+          '      try {\n'
+          '        WindowsPlugin.registerWith();\n'
+          '      } catch (err) {\n'
+          '        print(\n'
+          "          '`url_launcher_windows` threw an error: \$err. '\n"
+          "          'The app may not function as expected until you remove this plugin from pubspec.yaml'\n"
+          '        );\n'
+          '        rethrow;\n'
+          '      }\n'
+          '\n'
+          '    }\n'
+          '  }\n'
+          '\n'
+          '}\n'
+          '\n'
+          'typedef _UnaryFunction = dynamic Function(List<String> args);\n'
+          'typedef _NullaryFunction = dynamic Function();\n'
+          '\n'
+          'void main(List<String> args) {\n'
+          '  if (entrypoint.main is _UnaryFunction) {\n'
+          '    (entrypoint.main as _UnaryFunction)(args);\n'
+          '  } else {\n'
+          '    (entrypoint.main as _NullaryFunction)();\n'
+          '  }\n'
+          '}\n'
+          ,
+        );
+      }, overrides: <Type, Generator>{
+        FileSystem: () => fs,
+        ProcessManager: () => FakeProcessManager.any(),
+      });
+
       testUsingContext('Plugin without platform support throws tool exit', () async {
         flutterProject.isModule = false;