Enforce a policy on supported Gradle, Java, AGP, and KGP versions (#142000)

Policy per https://flutter.dev/go/android-dependency-versions.

https://github.com/flutter/flutter/issues/140913

~Still a WIP while I clean up some error handling, remove some prints, and figure out a Java test (more difficult than the others because I believe we can only install one java version per ci shard).~

~Also it looks like there are errors that I need to fix when this checking is applied to a project that uses the old way of applying AGP/KGP using the top-level `build.gradle` file (instead of the new template way of applying them in the `settings.gradle` file).~ Done, this is why [these lines exist](https://github.com/flutter/flutter/blob/9af6bae6b9a8d7a8a363467b834f52bfc64c9336/packages/flutter_tools/gradle/src/main/groovy/flutter.groovy#L72-L88) in `flutter.groovy`. They just needed to be added

packages/flutter_tools/gradle/build.gradle.kts

@@ -28,8 +28,9 @@ gradlePlugin {
 
 dependencies {
     // When bumping, also update:
-    //  * ndkVersion in FlutterExtension in packages/flutter_tools/gradle/src/main/flutter.groovy
+    //  * ndkVersion in FlutterExtension in packages/flutter_tools/gradle/src/main/groovy/flutter.groovy
+    //  * AGP version in the buildscript block in packages/flutter_tools/gradle/src/main/groovy/flutter.groovy
+    //  * AGP version in the buildscript block in packages/flutter_tools/gradle/src/main/kotlin/dependency_version_checker.gradle.kts
     //  * AGP version constants in packages/flutter_tools/lib/src/android/gradle_utils.dart
-    //  * AGP version in buildscript block in packages/flutter_tools/gradle/src/main/flutter.groovy
     compileOnly("com.android.tools.build:gradle:7.3.0")
 }

packages/flutter_tools/gradle/src/main/groovy/flutter.groovy

@@ -113,7 +113,8 @@ buildscript {
     }
     dependencies {
         // When bumping, also update:
-        //  * ndkVersion in FlutterExtension in packages/flutter_tools/gradle/src/main/flutter.groovy
+        //  * ndkVersion in FlutterExtension in packages/flutter_tools/gradle/src/main/groovy/flutter.groovy
+        //  * AGP version in the buildscript block in packages/flutter_tools/gradle/src/main/kotlin/dependency_version_checker.gradle.kts
         //  * AGP version constants in packages/flutter_tools/lib/src/android/gradle_utils.dart
         //  * AGP version in dependencies block in packages/flutter_tools/gradle/build.gradle.kts
         classpath("com.android.tools.build:gradle:7.3.0")
@@ -321,6 +322,23 @@ class FlutterPlugin implements Plugin<Project> {
         String flutterExecutableName = Os.isFamily(Os.FAMILY_WINDOWS) ? "flutter.bat" : "flutter"
         flutterExecutable = Paths.get(flutterRoot.absolutePath, "bin", flutterExecutableName).toFile()
 
+        // Validate that the provided Gradle, Java, AGP, and KGP versions are all within our
+        // supported range.
+        final Boolean shouldSkipDependencyChecks = project.hasProperty("skipDependencyChecks")
+                && project.getProperty("skipDependencyChecks");
+        if (!shouldSkipDependencyChecks) {
+            try {
+                final String dependencyCheckerPluginPath = Paths.get(flutterRoot.absolutePath,
+                        "packages", "flutter_tools", "gradle", "src", "main", "kotlin",
+                        "dependency_version_checker.gradle.kts")
+                project.apply from: dependencyCheckerPluginPath
+            } catch (Exception ignored) {
+                project.logger.error("Warning: Flutter was unable to detect project Gradle, Java, " +
+                        "AGP, and KGP versions. Skipping dependency version checking. Error was: "
+                        + ignored)
+            }
+        }
+
         // Use Kotlin DSL to handle baseApplicationName logic due to Groovy dynamic dispatch bug.
         project.apply from: Paths.get(flutterRoot.absolutePath, "packages", "flutter_tools", "gradle", "src", "main", "kotlin", "flutter.gradle.kts")
 
@@ -1515,6 +1533,8 @@ abstract class BaseFlutterTask extends DefaultTask {
     @Optional @Input
     Boolean validateDeferredComponents
 
+    @Optional @Input
+    Boolean skipDependencyChecks
     @Optional @Input
     String flavor
 

packages/flutter_tools/lib/src/android/README.md

@@ -29,6 +29,11 @@ version.
 SDK versions are updated (you should see these fail if you do not fix them
 preemptively).
 
+Also, make sure to also update to the same version in the following places:
+- The version in the buildscript block in `packages/flutter_tools/gradle/src/main/groovy/flutter.groovy`.
+- The version in the buildscript block in `packages/flutter_tools/gradle/src/main/kotlin/dependency_version_checker.gradle.kts`.
+- The version in the dependencies block in `packages/flutter_tools/gradle/build.gradle.kts`.
+
 #### Gradle
 When updating the Gradle version used in project templates
 (`templateDefaultGradleVersion`), make sure that:

packages/flutter_tools/lib/src/android/gradle.dart

@@ -370,6 +370,9 @@ class AndroidGradleBuilder implements AndroidBuilder {
     if (!buildInfo.androidGradleDaemon) {
       command.add('--no-daemon');
     }
+    if (buildInfo.androidSkipBuildDependencyValidation) {
+      command.add('-PskipDependencyChecks=true');
+    }
     final LocalEngineInfo? localEngineInfo = _artifacts.localEngineInfo;
     if (localEngineInfo != null) {
       final Directory localEngineRepo = _getLocalEngineRepo(

packages/flutter_tools/lib/src/build_info.dart

@@ -41,6 +41,7 @@ class BuildInfo {
     this.nullSafetyMode = NullSafetyMode.sound,
     this.codeSizeDirectory,
     this.androidGradleDaemon = true,
+    this.androidSkipBuildDependencyValidation = false,
     this.packageConfig = PackageConfig.empty,
     this.initializeFromDill,
     this.assumeInitializeFromDillUpToDate = false,
@@ -153,6 +154,10 @@ class BuildInfo {
   /// The Gradle daemon may also be disabled in the Android application's properties file.
   final bool androidGradleDaemon;
 
+  /// Whether to skip checking of individual versions of our Android build time
+  /// dependencies.
+  final bool androidSkipBuildDependencyValidation;
+
   /// Additional key value pairs that are passed directly to the gradle project via the `-P`
   /// flag.
   final List<String> androidProjectArgs;

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -147,6 +147,7 @@ abstract final class FlutterOptions {
   static const String kAndroidGradleDaemon = 'android-gradle-daemon';
   static const String kDeferredComponents = 'deferred-components';
   static const String kAndroidProjectArgs = 'android-project-arg';
+  static const String kAndroidSkipBuildDependencyValidation = 'android-skip-build-dependency-validation';
   static const String kInitializeFromDill = 'initialize-from-dill';
   static const String kAssumeInitializeFromDillUpToDate = 'assume-initialize-from-dill-up-to-date';
   static const String kNativeAssetsYamlFile = 'native-assets-yaml-file';
@@ -974,6 +975,12 @@ abstract class FlutterCommand extends Command<void> {
       defaultsTo: true,
       hide: hide,
     );
+    argParser.addFlag(
+      FlutterOptions.kAndroidSkipBuildDependencyValidation,
+      help: 'Whether to skip version checking for Java, Gradle, '
+          'the Android Gradle Plugin (AGP), and the Kotlin Gradle Plugin (KGP)'
+          ' during Android builds.',
+    );
     argParser.addMultiOption(
       FlutterOptions.kAndroidProjectArgs,
       help: 'Additional arguments specified as key=value that are passed directly to the gradle '
@@ -1228,6 +1235,9 @@ abstract class FlutterCommand extends Command<void> {
     final bool androidGradleDaemon = !argParser.options.containsKey(FlutterOptions.kAndroidGradleDaemon)
       || boolArg(FlutterOptions.kAndroidGradleDaemon);
 
+    final bool androidSkipBuildDependencyValidation = !argParser.options.containsKey(FlutterOptions.kAndroidSkipBuildDependencyValidation)
+        || boolArg(FlutterOptions.kAndroidSkipBuildDependencyValidation);
+
     final List<String> androidProjectArgs = argParser.options.containsKey(FlutterOptions.kAndroidProjectArgs)
       ? stringsArg(FlutterOptions.kAndroidProjectArgs)
       : <String>[];
@@ -1316,6 +1326,7 @@ abstract class FlutterCommand extends Command<void> {
       nullSafetyMode: nullSafetyMode,
       codeSizeDirectory: codeSizeDirectory,
       androidGradleDaemon: androidGradleDaemon,
+      androidSkipBuildDependencyValidation: androidSkipBuildDependencyValidation,
       packageConfig: packageConfig,
       androidProjectArgs: androidProjectArgs,
       initializeFromDill: argParser.options.containsKey(FlutterOptions.kInitializeFromDill)

packages/flutter_tools/test/android_preview_integration.shard/android_dependency_version_checking_test.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 'dart:io';
+
+import 'package:file/src/interface/file_system_entity.dart';
+
+import '../integration.shard/test_utils.dart';
+import '../src/common.dart';
+import '../src/context.dart';
+
+const String gradleSettingsFileContent = r'''
+pluginManagement {
+    def flutterSdkPath = {
+        def properties = new Properties()
+        file("local.properties").withInputStream { properties.load(it) }
+        def flutterSdkPath = properties.getProperty("flutter.sdk")
+        assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
+        return flutterSdkPath
+    }()
+
+    includeBuild("$flutterSdkPath/packages/flutter_tools/gradle")
+
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+plugins {
+    id "dev.flutter.flutter-plugin-loader" version "1.0.0"
+    id "com.android.application" version "AGP_REPLACE_ME" apply false
+    id "org.jetbrains.kotlin.android" version "KGP_REPLACE_ME" apply false
+}
+
+include ":app"
+
+''';
+
+const String agpReplacementString = 'AGP_REPLACE_ME';
+const String kgpReplacementString = 'KGP_REPLACE_ME';
+
+const String gradleWrapperPropertiesFileContent = r'''
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-GRADLE_REPLACE_ME-all.zip
+
+''';
+
+const String gradleReplacementString = 'GRADLE_REPLACE_ME';
+
+// This test is currently on the preview shard (but not using the preview
+// version of Android) because it is the only one using Java 11. This test
+// requires Java 11 due to the intentionally low version of Gradle.
+void main() {
+  late Directory tempDir;
+
+  setUpAll(() async {
+    tempDir = createResolvedTempDirectorySync('run_test.');
+  });
+
+  tearDownAll(() async {
+    tryToDelete(tempDir as FileSystemEntity);
+  });
+
+  testUsingContext(
+      'AGP version out of "warn" support band prints warning but still builds', () async {
+    // Create a new flutter project.
+    final String flutterBin = fileSystem.path.join(getFlutterRoot(), 'bin', 'flutter');
+    ProcessResult result = await processManager.run(<String>[
+      flutterBin,
+      'create',
+      'dependency_checker_app',
+      '--platforms=android',
+    ], workingDirectory: tempDir.path);
+    expect(result, const ProcessResultMatcher());
+    const String gradleVersion = '7.5';
+    const String agpVersion = '4.2.0';
+    const String kgpVersion = '1.7.10';
+
+    final Directory app = Directory(fileSystem.path.join(tempDir.path, 'dependency_checker_app'));
+
+    // Modify gradle version to passed in version.
+    final File gradleWrapperProperties = File(fileSystem.path.join(
+        app.path, 'android', 'gradle', 'wrapper', 'gradle-wrapper.properties'));
+    final String propertyContent = gradleWrapperPropertiesFileContent.replaceFirst(
+      gradleReplacementString,
+      gradleVersion,
+    );
+    await gradleWrapperProperties.writeAsString(propertyContent, flush: true);
+
+    final File gradleSettings = File(fileSystem.path.join(
+        app.path, 'android', 'settings.gradle'));
+    final String settingsContent = gradleSettingsFileContent
+        .replaceFirst(agpReplacementString, agpVersion)
+        .replaceFirst(kgpReplacementString, kgpVersion);
+    await gradleSettings.writeAsString(settingsContent, flush: true);
+
+
+    // Ensure that gradle files exists from templates.
+    result = await processManager.run(<String>[
+      flutterBin,
+      'build',
+      'apk',
+      '--debug',
+    ], workingDirectory: app.path);
+    expect(result, const ProcessResultMatcher());
+    expect(result.stderr, contains('Please upgrade your Android Gradle '
+        'Plugin version'));
+  });
+
+  testUsingContext(
+      'Gradle version out of "warn" support band prints warning but still builds', () async {
+    // Create a new flutter project.
+    final String flutterBin = fileSystem.path.join(getFlutterRoot(), 'bin', 'flutter');
+    ProcessResult result = await processManager.run(<String>[
+      flutterBin,
+      'create',
+      'dependency_checker_app',
+      '--platforms=android',
+    ], workingDirectory: tempDir.path);
+    expect(result, const ProcessResultMatcher());
+    const String gradleVersion = '7.0';
+    const String agpVersion = '4.2.0';
+    const String kgpVersion = '1.7.10';
+
+    final Directory app = Directory(fileSystem.path.join(tempDir.path, 'dependency_checker_app'));
+
+    // Modify gradle version to passed in version.
+    final File gradleWrapperProperties = File(fileSystem.path.join(
+        app.path, 'android', 'gradle', 'wrapper', 'gradle-wrapper.properties'));
+    final String propertyContent = gradleWrapperPropertiesFileContent.replaceFirst(
+      gradleReplacementString,
+      gradleVersion,
+    );
+    await gradleWrapperProperties.writeAsString(propertyContent, flush: true);
+
+    final File gradleSettings = File(fileSystem.path.join(
+        app.path, 'android', 'settings.gradle'));
+    final String settingsContent = gradleSettingsFileContent
+        .replaceFirst(agpReplacementString, agpVersion)
+        .replaceFirst(kgpReplacementString, kgpVersion);
+    await gradleSettings.writeAsString(settingsContent, flush: true);
+
+
+    // Ensure that gradle files exists from templates.
+    result = await processManager.run(<String>[
+      flutterBin,
+      'build',
+      'apk',
+      '--debug',
+    ], workingDirectory: app.path);
+    expect(result, const ProcessResultMatcher());
+    expect(result.stderr, contains('Please upgrade your Gradle version'));
+  });
+
+  testUsingContext(
+      'Kotlin version out of "warn" support band prints warning but still builds', () async {
+    // Create a new flutter project.
+    final String flutterBin = fileSystem.path.join(getFlutterRoot(), 'bin', 'flutter');
+    ProcessResult result = await processManager.run(<String>[
+      flutterBin,
+      'create',
+      'dependency_checker_app',
+      '--platforms=android',
+    ], workingDirectory: tempDir.path);
+    expect(result, const ProcessResultMatcher());
+    const String gradleVersion = '7.5';
+    const String agpVersion = '7.4.0';
+    const String kgpVersion = '1.4.10';
+
+    final Directory app = Directory(fileSystem.path.join(tempDir.path, 'dependency_checker_app'));
+
+    // Modify gradle version to passed in version.
+    final File gradleWrapperProperties = File(fileSystem.path.join(
+        app.path, 'android', 'gradle', 'wrapper', 'gradle-wrapper.properties'));
+    final String propertyContent = gradleWrapperPropertiesFileContent.replaceFirst(
+      gradleReplacementString,
+      gradleVersion,
+    );
+    await gradleWrapperProperties.writeAsString(propertyContent, flush: true);
+
+    final File gradleSettings = File(fileSystem.path.join(
+        app.path, 'android', 'settings.gradle'));
+    final String settingsContent = gradleSettingsFileContent
+        .replaceFirst(agpReplacementString, agpVersion)
+        .replaceFirst(kgpReplacementString, kgpVersion);
+    await gradleSettings.writeAsString(settingsContent, flush: true);
+
+
+    // Ensure that gradle files exists from templates.
+    result = await processManager.run(<String>[
+      flutterBin,
+      'build',
+      'apk',
+      '--debug',
+    ], workingDirectory: app.path);
+    expect(result, const ProcessResultMatcher());
+    expect(result.stderr, contains('Please upgrade your Kotlin version'));
+  });
+
+  // TODO(gmackall): Add tests for build blocking when the
+  // corresponding error versions are enabled.
+}