[flutter_tools] Format plugin example template to match dart format (#188382) The plugin example app generated by `flutter create -t plugin` fails `dart format`. The `example/lib/main.dart` it produces contains a line that exceeds 80 columns: ```dart platformVersion = await _<plugin>Plugin.getPlatformVersion() ?? 'Unknown platform version'; ``` This comes from the plugin-hook block in `templates/app/lib/main.dart.tmpl`. #187443 formatted the `--empty` block of this same file, but the plugin-hook block was left untouched. This PR wraps the line after `??` to match `dart format`'s output, so newly generated plugins are formatted out of the box. I confirmed the other `flutter create` templates (app default + `--empty`, module, package, plugin_ffi) are already clean, so this is the last remaining template that failed formatting. Fixes #175960. Adds a regression test (`has correct content and formatting with plugin template` in `create_test.dart`) that generates a plugin and asserts every generated `.dart` file is already `dart format`-clean, mirroring the existing app and module template formatting tests. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [AI contribution guidelines] and understand my responsibilities. (I used AI tooling for this change and have reviewed, understood, and verified it.) - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement]. - [x] I signed the [CLA]. - [x] I listed at least one issue that this PR fixes in the description above. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I added new tests to check the change I am making, or this PR is [test-exempt]. - [x] I followed the [breaking change policy] and added [Data Driven Fixes] where supported. - [x] All existing and new tests are passing. [Contributor Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview [AI contribution guidelines]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#ai-contribution-guidelines [Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md [test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests [Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md [Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement [CLA]: https://cla.developers.google.com/ [breaking change policy]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes [Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md --------- Co-authored-by: Ben Konyi <bkonyi@google.com>

diff --git a/packages/flutter_tools/templates/app/lib/main.dart.tmpl b/packages/flutter_tools/templates/app/lib/main.dart.tmpl
index 76eb18b..a23bfa4 100644
--- a/packages/flutter_tools/templates/app/lib/main.dart.tmpl
+++ b/packages/flutter_tools/templates/app/lib/main.dart.tmpl

@@ -18,12 +18,14 @@
 {{/withEmptyMain}}
 {{^withEmptyMain}}
 {{#withPlatformChannelPluginHook}}
+
 import 'dart:async';
 
 import 'package:flutter/services.dart';
 import 'package:{{pluginProjectName}}/{{pluginProjectName}}.dart';
 {{/withPlatformChannelPluginHook}}
 {{#withFfi}}
+
 import 'dart:async';
 
 import 'package:{{pluginProjectName}}/{{pluginProjectName}}.dart' as {{pluginProjectName}};
@@ -176,7 +178,8 @@
     // We also handle the message potentially returning null.
     try {
       platformVersion =
-          await _{{pluginClassLowerCamelCase}}.getPlatformVersion() ?? 'Unknown platform version';
+          await _{{pluginClassLowerCamelCase}}.getPlatformVersion() ??
+          'Unknown platform version';
     } on PlatformException {
       platformVersion = 'Failed to get platform version.';
     }

diff --git a/packages/flutter_tools/templates/plugin/test/projectName_test.dart.tmpl b/packages/flutter_tools/templates/plugin/test/projectName_test.dart.tmpl
index 028b08f..2d8d972 100644
--- a/packages/flutter_tools/templates/plugin/test/projectName_test.dart.tmpl
+++ b/packages/flutter_tools/templates/plugin/test/projectName_test.dart.tmpl

@@ -12,7 +12,7 @@
 }
 
 void main() {
-  final {{pluginDartClass}}Platform initialPlatform = {{pluginDartClass}}Platform.instance;
+  final initialPlatform = {{pluginDartClass}}Platform.instance;
 
   test('$MethodChannel{{pluginDartClass}} is the default instance', () {
     expect(initialPlatform, isInstanceOf<MethodChannel{{pluginDartClass}}>());

diff --git a/packages/flutter_tools/test/commands.shard/permeable/create_test.dart b/packages/flutter_tools/test/commands.shard/permeable/create_test.dart
index 59b683a..0772be2 100644
--- a/packages/flutter_tools/test/commands.shard/permeable/create_test.dart
+++ b/packages/flutter_tools/test/commands.shard/permeable/create_test.dart

@@ -1516,6 +1516,38 @@
     expect(sdkMetaContents, contains('/bin/cache/dart-sdk/lib/core"'));
   }, overrides: {FlutterVersion: () => fakeFlutterVersion, Platform: _kNoColorTerminalPlatform});
 
+  testUsingContext('has correct content and formatting with plugin template', () async {
+    final command = CreateCommand();
+    final CommandRunner<void> runner = createTestCommandRunner(command);
+
+    await runner.run(<String>[
+      'create',
+      '--template=plugin',
+      '--no-pub',
+      '--org',
+      'com.foo.bar',
+      projectDir.path,
+    ]);
+
+    // The generated plugin and its example app should already be formatted, so
+    // `flutter create -t plugin` output passes `dart format` out of the box.
+    // Regression test for https://github.com/flutter/flutter/issues/175960.
+    for (final FileSystemEntity file in projectDir.listSync(recursive: true)) {
+      if (file is File && file.path.endsWith('.dart')) {
+        final String original = file.readAsStringSync();
+
+        final Process process = await Process.start(
+          globals.artifacts!.getArtifactPath(Artifact.engineDartBinary),
+          <String>['format', '--output=show', file.path],
+          workingDirectory: projectDir.path,
+        );
+        final String formatted = await process.stdout.transform(utf8.decoder).join();
+
+        expect(formatted, contains(original), reason: file.path);
+      }
+    }
+  }, overrides: {FlutterVersion: () => fakeFlutterVersion, Platform: _kNoColorTerminalPlatform});
+
   testUsingContext(
     'has iOS development team with app template',
     () async {