[flutter_tool] Suggest how to increase the Android minSdkVersion (#82372)

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

@@ -73,6 +73,7 @@ final List<GradleHandledError> gradleErrors = <GradleHandledError>[
   flavorUndefinedHandler,
   r8FailureHandler,
   androidXFailureHandler,
+  minSdkVersion,
 ];
 
 // Permission defined error message.
@@ -352,3 +353,44 @@ final GradleHandledError flavorUndefinedHandler = GradleHandledError(
   },
   eventLabel: 'flavor-undefined',
 );
+
+
+final RegExp _minSdkVersionPattern = RegExp(r'uses-sdk:minSdkVersion ([0-9]+) cannot be smaller than version ([0-9]+) declared in library \[\:(.+)\]');
+
+/// Handler when a plugin requires a higher Android API level.
+@visibleForTesting
+final GradleHandledError minSdkVersion = GradleHandledError(
+  test: (String line) {
+    return _minSdkVersionPattern.hasMatch(line);
+  },
+  handler: ({
+    String line,
+    FlutterProject project,
+    bool usesAndroidX,
+    bool shouldBuildPluginAsAar,
+  }) async {
+    final File gradleFile = project.directory
+        .childDirectory('android')
+        .childDirectory('app')
+        .childFile('build.gradle');
+
+    final Match minSdkVersionMatch = _minSdkVersionPattern.firstMatch(line);
+    assert(minSdkVersionMatch.groupCount == 3);
+
+    globals.printStatus(
+      '\nThe plugin ${minSdkVersionMatch.group(3)} requires a higher Android SDK version.\n'+
+      globals.logger.terminal.bolden(
+        'Fix this issue by adding the following to the file ${gradleFile.path}:\n'
+        'android {\n'
+        '  defaultConfig {\n'
+        '    minSdkVersion ${minSdkVersionMatch.group(2)}\n'
+        '  }\n'
+        '}\n\n'
+      )+
+      'Note that your app won\'t be available to users running Android SDKs below ${minSdkVersionMatch.group(2)}.\n'
+      'Alternatively, try to find a version of this plugin that supports these lower versions of the Android SDK.'
+    );
+    return GradleBuildStatus.exit;
+  },
+  eventLabel: 'plugin-min-sdk',
+);

packages/flutter_tools/test/general.shard/android/gradle_errors_test.dart

@@ -29,6 +29,7 @@ void main() {
           flavorUndefinedHandler,
           r8FailureHandler,
           androidXFailureHandler,
+          minSdkVersion,
         ])
       );
     });
@@ -646,6 +647,47 @@ assembleProfile
       FileSystem: () => MemoryFileSystem.test(),
     });
   });
+
+  group('higher minSdkVersion', () {
+    const String stdoutLine = 'uses-sdk:minSdkVersion 16 cannot be smaller than version 19 declared in library [:webview_flutter] /tmp/cirrus-ci-build/all_plugins/build/webview_flutter/intermediates/library_manifest/release/AndroidManifest.xml as the library might be using APIs not available in 16';
+
+    testWithoutContext('pattern', () {
+      expect(
+        minSdkVersion.test(stdoutLine),
+        isTrue,
+      );
+    });
+
+    testUsingContext('suggestion', () async {
+      await minSdkVersion.handler(
+        line: stdoutLine,
+        project: FlutterProject.fromDirectoryTest(globals.fs.currentDirectory),
+      );
+
+      expect(
+        testLogger.statusText,
+        contains(
+          '\n'
+          'The plugin webview_flutter requires a higher Android SDK version.\n'
+          'Fix this issue by adding the following to the file /android/app/build.gradle:\n'
+          'android {\n'
+          '  defaultConfig {\n'
+          '    minSdkVersion 19\n'
+          '  }\n'
+          '}\n'
+          '\n'
+          'Note that your app won\'t be available to users running Android SDKs below 19.\n'
+          'Alternatively, try to find a version of this plugin that supports these lower versions of the Android SDK.\n'
+          ''
+        )
+      );
+    }, overrides: <Type, Generator>{
+      GradleUtils: () => FakeGradleUtils(),
+      Platform: () => fakePlatform('android'),
+      FileSystem: () => MemoryFileSystem.test(),
+      ProcessManager: () => FakeProcessManager.empty(),
+    });
+  });
 }
 
 bool formatTestErrorMessage(String errorMessage, GradleHandledError error) {