Set up Kotlin linting step in ci with ktlint (#143478)

Adds a kotlin linting step to the linux analyze check, using a version of [ktlint](https://github.com/pinterest/ktlint) hosted on [CIPD](https://chrome-infra-packages.appspot.com/p/flutter/ktlint/linux-amd64/+/version_1_1_1).

Configured to disallow trailing commas, because of (and now acting as a test for) https://github.com/flutter/flutter/pull/145718. Because of this configuration the PR also removes some trailing commas in some kotlin files.

Also checks in a baseline file.

.ci.yaml

@@ -298,6 +298,10 @@ targets:
     timeout: 60
     properties:
       shard: analyze
+      dependencies: >-
+        [
+          {"dependency": "ktlint", "version": "version_1_1_1"}
+        ]
       tags: >
         ["framework","hostonly","shard","linux"]
 

dev/benchmarks/multiple_flutters/android/app/src/main/java/dev/flutter/multipleflutters/MainActivity.kt

@@ -23,7 +23,7 @@ class MainActivity : FragmentActivity() {
         root.layoutParams =
             LinearLayout.LayoutParams(
                 LinearLayout.LayoutParams.MATCH_PARENT,
-                LinearLayout.LayoutParams.MATCH_PARENT,
+                LinearLayout.LayoutParams.MATCH_PARENT
             )
         root.orientation = LinearLayout.VERTICAL
         root.weightSum = numberOfFlutters.toFloat()
@@ -36,7 +36,7 @@ class MainActivity : FragmentActivity() {
         val dartEntrypoint =
             DartExecutor.DartEntrypoint(
                 FlutterInjector.instance().flutterLoader().findAppBundlePath(),
-                "main",
+                "main"
             )
         val engines =
             generateSequence(0) { it + 1 }
@@ -51,7 +51,7 @@ class MainActivity : FragmentActivity() {
                 LinearLayout.LayoutParams(
                     FrameLayout.LayoutParams.MATCH_PARENT,
                     FrameLayout.LayoutParams.MATCH_PARENT,
-                    1.0f,
+                    1.0f
                 )
             val engine = engines[i]
             FlutterEngineCache.getInstance().put(i.toString(), engine)
@@ -61,7 +61,7 @@ class MainActivity : FragmentActivity() {
                 .beginTransaction()
                 .add(
                     12345 + i,
-                    flutterFragment,
+                    flutterFragment
                 )
                 .commit()
         }

dev/benchmarks/platform_channels_benchmarks/android/app/src/main/kotlin/com/example/platform_channels_benchmarks/MainActivity.kt

@@ -43,7 +43,7 @@ class MainActivity : FlutterActivity() {
                 flutterEngine.dartExecutor,
                 "dev.flutter.echo.background.standard",
                 StandardMessageCodec.INSTANCE,
-                taskQueue,
+                taskQueue
             )
         backgroundStandard.setMessageHandler { message, reply -> reply.reply(message) }
         super.configureFlutterEngine(flutterEngine)

dev/bots/analyze.dart

@@ -153,6 +153,9 @@ Future<void> run(List<String> arguments) async {
   printProgress('Taboo words...');
   await verifyTabooDocumentation(flutterRoot);
 
+  printProgress('Lint Kotlin files...');
+  await lintKotlinFiles(flutterRoot);
+
   // Ensure that all package dependencies are in sync.
   printProgress('Package dependencies...');
   await runCommand(flutter, <String>['update-packages', '--verify-only'],
@@ -1973,6 +1976,22 @@ Future<void> verifyTabooDocumentation(String workingDirectory, { int minimumMatc
   }
 }
 
+Future<void> lintKotlinFiles(String workingDirectory) async {
+  const String baselineRelativePath = 'dev/bots/test/analyze-test-input/ktlint-baseline.xml';
+  const String editorConfigRelativePath = 'dev/bots/test/analyze-test-input/.editorconfig';
+  final EvalResult lintResult = await _evalCommand('ktlint',
+      <String>['--baseline=$flutterRoot/$baselineRelativePath', '--editorconfig=$flutterRoot/$editorConfigRelativePath'],
+      workingDirectory: workingDirectory);
+  if (lintResult.exitCode != 0) {
+    final String errorMessage = 'Found lint violations in Kotlin files:\n ${lintResult.stdout}\n\n'
+        'To reproduce this lint locally:\n'
+        '1. Identify the CIPD version tag used to resolve this particular version of ktlint (check the dependencies section of this shard in the ci.yaml). \n'
+        '2. Download that version from https://chrome-infra-packages.appspot.com/p/flutter/ktlint/linux-amd64/+/<version_tag>\n'
+        '3. From the repository root, run `<path_to_ktlint>/ktlint --editorconfig=$editorConfigRelativePath --baseline=$baselineRelativePath`';
+    foundError(<String>[errorMessage]);
+  }
+}
+
 const List<String> _kIgnoreList = <String>[
   'Runner.rc.tmpl',
   'flutter_window.cpp',

dev/bots/test/analyze-test-input/.editorconfig

@@ -0,0 +1,4 @@
+[*.{kt,kts}]
+# Disable trailing commas to allow compatibility with Kotlin versions less than 1.4.
+ij_kotlin_allow_trailing_comma = false
+ij_kotlin_allow_trailing_comma_on_call_site = false

dev/bots/test/analyze-test-input/ktlint-baseline.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<baseline version="1.0">
+    <file name="dev/a11y_assessments/android/app/src/main/kotlin/com/example/a11y_assessments/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+    <file name="dev/benchmarks/platform_channels_benchmarks/android/app/src/main/kotlin/com/example/platform_channels_benchmarks/MainActivity.kt">
+        <error line="5" column="9" source="standard:package-name" />
+    </file>
+    <file name="dev/integration_tests/abstract_method_smoke_test/android/app/src/main/kotlin/com/example/abstract_method_smoke_test/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+    <file name="dev/integration_tests/android_embedding_v2_smoke_test/android/app/src/main/kotlin/com/example/android_embedding_v2_smoke_test/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+    <file name="dev/integration_tests/deferred_components_test/android/app/src/main/kotlin/io/flutter/integration/deferred_components_test/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+    <file name="dev/integration_tests/non_nullable/android/app/src/main/kotlin/com/example/non_nullable/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+    <file name="dev/integration_tests/spell_check/android/app/src/main/kotlin/com/example/sc_int_test/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+    <file name="dev/manual_tests/android/app/src/main/kotlin/dev/flutter/manual_tests/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+    <file name="dev/tracing_tests/android/app/src/main/kotlin/com/example/tracing_tests/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+    <file name="examples/api/android/app/src/main/kotlin/dev/flutter/flutter_api_samples/MainActivity.kt">
+        <error line="1" column="9" source="standard:package-name" />
+    </file>
+</baseline>

dev/integration_tests/abstract_method_smoke_test/android/app/src/main/kotlin/com/example/abstract_method_smoke_test/MainActivity.kt

@@ -30,7 +30,7 @@ class MainActivity : FlutterActivity() {
     }
 
     override fun configureFlutterEngine(
-        @NonNull flutterEngine: FlutterEngine,
+        @NonNull flutterEngine: FlutterEngine
     ) {
         GeneratedPluginRegistrant.registerWith(flutterEngine)
 
@@ -43,11 +43,11 @@ class MainActivity : FlutterActivity() {
                     override fun create(
                         context: Context?,
                         viewId: Int,
-                        args: Any?,
+                        args: Any?
                     ): PlatformView {
                         return SimplePlatformView(this@MainActivity)
                     }
-                },
+                }
             )
 
         // Triggers the Android keyboard, which causes the resize of the Flutter view.

dev/integration_tests/android_embedding_v2_smoke_test/android/app/src/main/kotlin/com/example/android_embedding_v2_smoke_test/MainActivity.kt

@@ -7,7 +7,7 @@ import io.flutter.plugins.GeneratedPluginRegistrant
 
 class MainActivity : FlutterActivity() {
     override fun configureFlutterEngine(
-        @NonNull flutterEngine: FlutterEngine,
+        @NonNull flutterEngine: FlutterEngine
     ) {
         GeneratedPluginRegistrant.registerWith(flutterEngine)
     }