[webview] [iOS Simulator] crash in [WKUserContentController _addScriptMessageHandler:] #141242
Description
Steps to reproduce
- using iOS simulator, iOS 16.4
- using xcode 14.3.1 (14E300c)
- macOS 13.6.3
- flutter 3.16.5
- click the "debug" button that pops up next to
void main() => runApp(const MyApp());in the ide - code crashes in
[WKUserContentController _addScriptMessageHandler:]
Expected results
No crash
Actual results
crash:
-------------------------------------
Translated Report (Full Report Below)
-------------------------------------
Incident Identifier: D1905BF3-3983-424B-9FF6-B0502311FD90
CrashReporter Key: 4E780D4D-F19E-AFBA-4394-B2658DB81148
Hardware Model: MacBookPro18,3
Process: Runner [9288]
Path: /Users/USER/Library/Developer/CoreSimulator/Devices/3CC4A744-C6BC-4E0F-B0BD-9592007F12A4/data/Containers/Bundle/Application/2B2868F5-2681-4A22-AC42-8392AD1BA840/Runner.app/Runner
Identifier: com.example.jamcorderFlutterApp
Version: 1.0.0 (1.0.0)
Code Type: ARM-64 (Native)
Role: Foreground
Parent Process: launchd_sim [1961]
Coalition: com.apple.CoreSimulator.SimDevice.3CC4A744-C6BC-4E0F-B0BD-9592007F12A4 [911]
Responsible Process: SimulatorTrampoline [1937]
Date/Time: 2024-01-10 01:58:09.9383 -0600
Launch Time: 2024-01-10 01:58:07.4407 -0600
OS Version: macOS 13.6.3 (22G436)
Release Type: User
Report Version: 104
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Termination Reason: SIGNAL 6 Abort trap: 6
Terminating Process: Runner [9288]
Triggered by Thread: 0
Last Exception Backtrace:
0 CoreFoundation 0x180437324 __exceptionPreprocess + 160
1 libobjc.A.dylib 0x180051274 objc_exception_throw + 56
2 CoreFoundation 0x180437240 -[NSException initWithCoder:] + 0
3 WebKit 0x10b92c35c -[WKUserContentController _addScriptMessageHandler:] + 104
4 WebKit 0x10b92c484 -[WKUserContentController addScriptMessageHandler:name:] + 176
5 webview_flutter_wkwebview 0x100e7d250 -[FWFUserContentControllerHostApiImpl addScriptMessageHandlerForControllerWithIdentifier:handlerIdentifier:ofName:error:] + 168 (FWFUserContentControllerHostApi.m:41)
6 webview_flutter_wkwebview 0x100e64790 __SetUpFWFWKUserContentControllerHostApi_block_invoke_2 + 296 (FWFGeneratedWebKitApis.m:1413)
7 Flutter 0x10494592c __48-[FlutterBasicMessageChannel setMessageHandler:]_block_invoke + 160
8 Flutter 0x10436478c invocation function for block in flutter::PlatformMessageHandlerIos::HandlePlatformMessage(std::_LIBCPP_ABI_NAMESPACE::unique_ptr<flutter::PlatformMessage, std::_LIBCPP_ABI_NAMESPACE::default_delete<flutter::PlatformMessage>>) + 108
9 libdispatch.dylib 0x180132ee4 _dispatch_call_block_and_release + 24
10 libdispatch.dylib 0x180134708 _dispatch_client_callout + 16
11 libdispatch.dylib 0x180143fd8 _dispatch_main_queue_drain + 1220
12 libdispatch.dylib 0x180143b04 _dispatch_main_queue_callback_4CF + 40
13 CoreFoundation 0x18039a784 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12
14 CoreFoundation 0x180394de4 __CFRunLoopRun + 1912
15 CoreFoundation 0x180394254 CFRunLoopRunSpecific + 584
16 GraphicsServices 0x188eb7c9c GSEventRunModal + 160
17 UIKitCore 0x10e1ceff0 -[UIApplication _run] + 868
18 UIKitCore 0x10e1d2f3c UIApplicationMain + 124
19 Runner 0x100a62fd0 main + 64 (AppDelegate.swift:5)
20 dyld_sim 0x100d1d514 start_sim + 20
21 dyld 0x100aadf28 start + 2236
22 ??? 0xe739000000000000 ???
Code sample
html (Edit: it turns out I was forgetting to invoke this html code. So you can ignore it)
<!DOCTYPE html>
<html>
<head>
<title>Calculation</title>
<script type="text/javascript">
function startCalculation() {
var progress = 0;
var interval = setInterval(function() {
progress++;
if (progress <= 100) {
CalculationResult.postMessage(progress + '% completed');
} else {
clearInterval(interval);
CalculationResult.postMessage('Result of calculation');
}
}, 100); // Adjust this for your calculation
}
</script>
</head>
<body>
<h1>Calculation Page</h1>
</body>
</html>dart
import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';
void main() => runApp(const MyApp());
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(
home: HomePage(),
);
}
}
class HomePage extends StatefulWidget {
const HomePage({super.key});
@override
State<HomePage> createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
late WebViewController _controller;
double _progress = 0;
bool _isLoading = false;
void _runComplexCalculation() {
setState(() {
_isLoading = true;
});
_controller.runJavaScript("startCalculation();");
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text("WebView Calculation"),
),
body: Stack(
children: [
Opacity(
opacity: 0.0,
child: WebViewWidget(
controller: _controller = WebViewController()
..setJavaScriptMode(JavaScriptMode.unrestricted)
..setNavigationDelegate(
NavigationDelegate(
onProgress: (int progress) {
setState(() {
_progress = progress / 100;
});
},
onPageFinished: (String url) {
_controller.addJavaScriptChannel("CalculationResult", onMessageReceived: _onMessageReceived);
},
),
)
..loadRequest(Uri.parse('about:blank')),
),
),
if (_isLoading)
LinearProgressIndicator(
value: _progress,
backgroundColor: Colors.grey[200],
valueColor: const AlwaysStoppedAnimation<Color>(Colors.blue),
),
Center(
child: ElevatedButton(
onPressed: _runComplexCalculation,
child: const Text('Render'),
),
),
],
),
);
}
void _onMessageReceived(JavaScriptMessage message) {
setState(() {
_isLoading = false;
_progress = 0;
});
// ignore: avoid_print
print(message.message); // Handle the calculation result here
}
}Flutter Doctor output
Doctor output
chipweinberger@Chips-MacBook-Pro jamcorder_flutter_app % flutter doctor --verbose
[✓] Flutter (Channel stable, 3.16.5, on macOS 13.6.3 22G436 darwin-arm64, locale en-US)
• Flutter version 3.16.5 on channel stable at /Volumes/User/MBP-Google-Drive/jamcorder/app/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 78666c8dc5 (3 weeks ago), 2023-12-19 16:14:14 -0800
• Engine revision 3f3e560236
• Dart version 3.2.3
• DevTools version 2.28.4
[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
• Android SDK at /Users/chipweinberger/Library/Android/sdk
• Platform android-34, build-tools 34.0.0
• Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b802.4-9586694)
• All Android licenses accepted.
[✓] Xcode - develop for iOS and macOS (Xcode 14.3.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Build 14E300c
• CocoaPods version 1.12.1
[✓] Chrome - develop for the web
• Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
[✓] Android Studio (version 2022.2)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/9212-flutter
• Dart plugin can be installed from:
🔨 https://plugins.jetbrains.com/plugin/6351-dart
• Java version OpenJDK Runtime Environment (build 17.0.6+0-17.0.6b802.4-9586694)
[✓] VS Code (version 1.85.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.80.0
[✓] Connected device (4 available)
• ChipsiPhone (mobile) • 00008101-000A0D1E3C90001E • ios • iOS 16.7.2 20H115
• iPhone 14 Pro Max (mobile) • 3CC4A744-C6BC-4E0F-B0BD-9592007F12A4 • ios • com.apple.CoreSimulator.SimRuntime.iOS-16-4 (simulator)
• macOS (desktop) • macos • darwin-arm64 • macOS 13.6.3 22G436 darwin-arm64
• Chrome (web) • chrome • web-javascript • Google Chrome 120.0.6099.216
[✓] Network resources
• All expected network resources are available.