[various] Fixes unawaited_futures violations (#4067)

This option had been disabled to match flutter/flutter, but the reason it was disabled there was "too many false positives", mostly around animation. That doesn't apply to most packages here, and we've had a number of production bugs�especially in plugins, that use async heavily in ways that are intended to be client-awaitable�that this would have caught.

This PR:
- Enables the option at the repo level.
- Permanently (unless the owners decide to change it) opts out `animations` and `go_router`, both of which looked like mostly or entirely false positives.
- Temporarily opted out a few plugins that have a lot of violations that should be handled in their own PRs later (`camera_android_camerax`, most of `webview_flutter`).
- Fixes all remaining violations.

In many cases this PR is behavior-changing, replacing implicitly unawaited futures that did not seem obviously intentional with `await`ed futures, so non-test code in particular should be reviewed carefully to make sure the changes are correct. All of the changes are manual, not `fix`-generated.

Part of flutter/flutter#127323

Author: stuartmorgan-g

analysis_options.yaml

@@ -183,7 +183,7 @@ linter:
     - tighten_type_of_initializing_formals
     # - type_annotate_public_apis # subset of always_specify_types
     - type_init_formals
-    # - unawaited_futures # too many false positives, especially with the way AnimationController works
+    - unawaited_futures # DIFFERENT FROM FLUTTER/FLUTTER: It's disabled there for "too many false positives"; that's not an issue here, and missing awaits have caused production issues in plugins.
     - unnecessary_await_in_return
     - unnecessary_brace_in_string_interps
     - unnecessary_const

packages/animations/analysis_options.yaml

@@ -0,0 +1,10 @@
+# This custom rule set only exists to allow opting out of the repository
+# default of enabling unawaited_futures. Please do NOT add more changes
+# here without consulting with #hackers-ecosystem on Discord.
+
+include: ../../analysis_options.yaml
+
+linter:
+  rules:
+    # Matches flutter/flutter, which disables this rule due to false positives.
+    unawaited_futures: false

packages/camera/camera/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.10.5+2
+
+* Fixes unawaited_futures violations.
+
 ## 0.10.5+1
 
 * Removes obsolete null checks on non-nullable values.

packages/camera/camera/lib/src/camera_controller.dart

@@ -552,7 +552,7 @@ class CameraController extends ValueNotifier<CameraValue> {
     }
 
     if (value.isStreamingImages) {
-      stopImageStream();
+      await stopImageStream();
     }
 
     try {

packages/camera/camera/pubspec.yaml

@@ -4,7 +4,7 @@ description: A Flutter plugin for controlling the camera. Supports previewing
   Dart.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.10.5+1
+version: 0.10.5+2
 
 environment:
   sdk: ">=2.18.0 <4.0.0"

packages/camera/camera/test/camera_image_stream_test.dart

@@ -174,7 +174,7 @@ void main() {
 
     await cameraController.initialize();
 
-    cameraController.startVideoRecording(
+    await cameraController.startVideoRecording(
         onAvailable: (CameraImage image) => null);
 
     expect(
@@ -192,7 +192,7 @@ void main() {
 
     await cameraController.initialize();
 
-    cameraController.startVideoRecording();
+    await cameraController.startVideoRecording();
 
     expect(mockPlatform.streamCallLog.contains('startVideoCapturing'), isTrue);
   });

packages/camera/camera_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+* Fixes unawaited_futures violations.
+
 ## 0.10.8+2
 
 * Removes obsolete null checks on non-nullable values.

packages/camera/camera_android/example/lib/camera_controller.dart

@@ -229,12 +229,12 @@ class CameraController extends ValueNotifier<CameraValue> {
       enableAudio: enableAudio,
     );
 
-    CameraPlatform.instance
+    unawaited(CameraPlatform.instance
         .onCameraInitialized(_cameraId)
         .first
         .then((CameraInitializedEvent event) {
       initializeCompleter.complete(event);
-    });
+    }));
 
     await CameraPlatform.instance.initializeCamera(
       _cameraId,
@@ -444,8 +444,8 @@ class CameraController extends ValueNotifier<CameraValue> {
     if (_isDisposed) {
       return;
     }
-    _deviceOrientationSubscription?.cancel();
     _isDisposed = true;
+    await _deviceOrientationSubscription?.cancel();
     super.dispose();
     if (_initCalled != null) {
       await _initCalled;

packages/camera/camera_android/test/android_camera_test.dart

@@ -1119,7 +1119,7 @@ void main() {
         isMethodCall('startImageStream', arguments: null),
       ]);
 
-      subscription.cancel();
+      await subscription.cancel();
     });
 
     test('Should stop streaming', () async {
@@ -1136,7 +1136,7 @@ void main() {
       final StreamSubscription<CameraImageData> subscription = camera
           .onStreamedFrameAvailable(cameraId)
           .listen((CameraImageData imageData) {});
-      subscription.cancel();
+      await subscription.cancel();
 
       // Assert
       expect(channel.log, <Matcher>[

packages/camera/camera_android_camerax/analysis_options.yaml

@@ -0,0 +1,8 @@
+# TODO(stuartmorgan): Remove this file and fix all the unawaited_futures
+# violations. See https://github.com/flutter/flutter/issues/127323
+
+include: ../../../analysis_options.yaml
+
+linter:
+  rules:
+    unawaited_futures: false

packages/camera/camera_avfoundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+* Fixes unawaited_futures violations.
+
 ## 0.9.13+2
 
 * Removes obsolete null checks on non-nullable values.

packages/camera/camera_avfoundation/example/lib/camera_controller.dart

@@ -229,12 +229,12 @@ class CameraController extends ValueNotifier<CameraValue> {
       enableAudio: enableAudio,
     );
 
-    CameraPlatform.instance
+    unawaited(CameraPlatform.instance
         .onCameraInitialized(_cameraId)
         .first
         .then((CameraInitializedEvent event) {
       initializeCompleter.complete(event);
-    });
+    }));
 
     await CameraPlatform.instance.initializeCamera(
       _cameraId,
@@ -443,8 +443,8 @@ class CameraController extends ValueNotifier<CameraValue> {
     if (_isDisposed) {
       return;
     }
-    _deviceOrientationSubscription?.cancel();
     _isDisposed = true;
+    await _deviceOrientationSubscription?.cancel();
     super.dispose();
     if (_initCalled != null) {
       await _initCalled;

packages/camera/camera_avfoundation/test/avfoundation_camera_test.dart

@@ -1120,7 +1120,7 @@ void main() {
         isMethodCall('startImageStream', arguments: null),
       ]);
 
-      subscription.cancel();
+      await subscription.cancel();
     });
 
     test('Should stop streaming', () async {
@@ -1137,7 +1137,7 @@ void main() {
       final StreamSubscription<CameraImageData> subscription = camera
           .onStreamedFrameAvailable(cameraId)
           .listen((CameraImageData imageData) {});
-      subscription.cancel();
+      await subscription.cancel();
 
       // Assert
       expect(channel.log, <Matcher>[

packages/camera/camera_platform_interface/test/method_channel/method_channel_camera_test.dart

@@ -1085,7 +1085,7 @@ void main() {
           isMethodCall('startImageStream', arguments: null),
         ]);
 
-        subscription.cancel();
+        await subscription.cancel();
       });
 
       test('Should stop streaming', () async {
@@ -1102,7 +1102,7 @@ void main() {
         final StreamSubscription<CameraImageData> subscription = camera
             .onStreamedFrameAvailable(cameraId)
             .listen((CameraImageData imageData) {});
-        subscription.cancel();
+        await subscription.cancel();
 
         // Assert
         expect(channel.log, <Matcher>[

packages/camera/camera_windows/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 0.2.1+7
 
+* Fixes unawaited_futures violations.
 * Updates minimum supported SDK version to Flutter 3.3/Dart 2.18.
 
 ## 0.2.1+6

packages/camera/camera_windows/example/lib/main.dart

@@ -99,12 +99,12 @@ class _MyAppState extends State<MyApp> {
         enableAudio: _recordAudio,
       );
 
-      _errorStreamSubscription?.cancel();
+      unawaited(_errorStreamSubscription?.cancel());
       _errorStreamSubscription = CameraPlatform.instance
           .onCameraError(cameraId)
           .listen(_onCameraError);
 
-      _cameraClosingStreamSubscription?.cancel();
+      unawaited(_cameraClosingStreamSubscription?.cancel());
       _cameraClosingStreamSubscription = CameraPlatform.instance
           .onCameraClosing(cameraId)
           .listen(_onCameraClosing);
@@ -193,7 +193,7 @@ class _MyAppState extends State<MyApp> {
 
   Future<void> _recordTimed(int seconds) async {
     if (_initialized && _cameraId > 0 && !_recordingTimed) {
-      CameraPlatform.instance
+      unawaited(CameraPlatform.instance
           .onVideoRecordedEvent(_cameraId)
           .first
           .then((VideoRecordedEvent event) async {
@@ -204,7 +204,7 @@ class _MyAppState extends State<MyApp> {
 
           _showInSnackBar('Video captured to: ${event.file.path}');
         }
-      });
+      }));
 
       await CameraPlatform.instance.startVideoRecording(
         _cameraId,

packages/camera/camera_windows/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_windows
 description: A Flutter plugin for getting information about and controlling the camera on Windows.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_windows
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.2.1+6
+version: 0.2.1+7
 
 environment:
   sdk: ">=2.18.0 <4.0.0"

packages/cross_file/tool/run_tests.dart

@@ -8,6 +8,7 @@
 //
 // usage: dart run tool/run_tests.dart
 // (needs a `chrome` executable in $PATH, or a tweak to dart_test.yaml)
+import 'dart:async';
 import 'dart:io';
 import 'package:path/path.dart' as p;
 
@@ -30,8 +31,8 @@ Future<void> main(List<String> args) async {
 
 Future<Process> _streamOutput(Future<Process> processFuture) async {
   final Process process = await processFuture;
-  stdout.addStream(process.stdout);
-  stderr.addStream(process.stderr);
+  unawaited(stdout.addStream(process.stdout));
+  unawaited(stderr.addStream(process.stderr));
   return process;
 }
 

packages/flutter_image/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 4.1.6
 
+* Fixes unawaited_futures violations.
 * Updates minimum supported SDK version to Flutter 3.3/Dart 2.18.
 * Aligns Dart and Flutter SDK constraints.
 

packages/flutter_image/lib/network.dart

@@ -191,7 +191,7 @@ class NetworkImageWithRetry extends ImageProvider<NetworkImageWithRetry> {
           scale: key.scale,
         );
       } catch (error) {
-        request?.close();
+        await request?.close();
         lastFailure = error is FetchFailure
             ? error
             : FetchFailure._(

packages/flutter_image/pubspec.yaml

@@ -3,7 +3,7 @@ description: >
   Image utilities for Flutter: improved network providers, effects, etc.
 repository: https://github.com/flutter/packages/tree/main/packages/flutter_image
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+flutter_image%22
-version: 4.1.5
+version: 4.1.6
 
 environment:
   sdk: ">=2.18.0 <4.0.0"

packages/flutter_markdown/CHANGELOG.md

@@ -1,5 +1,6 @@
 ## NEXT
 
+* Fixes unawaited_futures violations.
 * Updates minimum Flutter version to 3.3.
 * Aligns Dart and Flutter SDK constraints.
 * Replace `describeEnum` with the `name` getter.

packages/flutter_markdown/example/lib/demos/basic_markdown_demo.dart

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_markdown/flutter_markdown.dart';
@@ -125,11 +127,11 @@ class _BasicMarkdownDemoState extends State<BasicMarkdownDemo> {
     String? href,
     String title,
   ) async {
-    showDialog<Widget>(
+    unawaited(showDialog<Widget>(
       context: context,
       builder: (BuildContext context) =>
           _createDialog(context, text, href, title),
-    );
+    ));
   }
 
   Widget _createDialog(

packages/flutter_markdown/example/lib/screens/demo_screen.dart

@@ -109,7 +109,7 @@ class DemoNotesView extends StatelessWidget {
     String? href,
     String title,
   ) async {
-    showDialog<Widget>(
+    await showDialog<Widget>(
       context: context,
       builder: (BuildContext context) =>
           _createDialog(context, text, href, title),

packages/go_router/analysis_options.yaml

@@ -1,5 +1,11 @@
+# This custom rule set only exists to allow very targeted changes
+# relative to the default repo settings, for specific use cases.
+# Please do NOT add more changes here without consulting with
+# #hackers-ecosystem on Discord.
+
 include: ../../analysis_options.yaml
 
 analyzer:
   exclude:
+    # This directory deliberately has errors, to test `fix`.
     - "test_fixes/**"

packages/go_router/test/analysis_options.yaml

@@ -0,0 +1,12 @@
+# This custom rule set only exists to allow very targeted changes
+# relative to the default repo settings, for specific use cases.
+# Please do NOT add more changes here without consulting with
+# #hackers-ecosystem on Discord.
+
+include: ../../../analysis_options.yaml
+
+linter:
+  rules:
+    # Matches flutter/flutter, which disables this rule due to false positives
+    # from navigator APIs.
+    unawaited_futures: false

packages/go_router/test/go_router_test.dart

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// ignore_for_file: cascade_invocations, diagnostic_describe_all_properties
+// ignore_for_file: cascade_invocations, diagnostic_describe_all_properties, unawaited_futures
 
 import 'dart:async';
 

packages/go_router/tool/run_tests.dart

@@ -8,6 +8,7 @@
 
 // ignore_for_file: avoid_print
 
+import 'dart:async';
 import 'dart:io';
 import 'package:io/io.dart' as io;
 import 'package:path/path.dart' as p;
@@ -99,8 +100,8 @@ dependencies:
 
 Future<Process> _streamOutput(Future<Process> processFuture) async {
   final Process process = await processFuture;
-  stdout.addStream(process.stdout);
-  stderr.addStream(process.stderr);
+  unawaited(stdout.addStream(process.stdout));
+  unawaited(stderr.addStream(process.stderr));
   return process;
 }
 

packages/go_router_builder/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 2.0.2
 
+* Fixes unawaited_futures violations.
 * Updates minimum supported SDK version to Flutter 3.3/Dart 2.18.
 
 ## 2.0.1