SizedBox with zero size throws Failed assertion: ... 'width > 0.0': is not true, Proposal to improve error message if SizedBox has zero size #135082
Description
Is there an existing issue for this?
- I have searched the existing issues
- I have read the guide to filing a bug
Steps to reproduce
- Write the following
const Row(
children: [
FittedBox(
child: SizedBox(
height: 0,
width: 0,
),
),
],
),- Run
Expected results
Nothing to be displayed as the widget is effectively zero sized.
Actual results
The following assertion was thrown during performLayout():
'package:flutter/src/rendering/box.dart': Failed assertion: line 320 pos 12: 'width > 0.0': is not true.
box.dart:320
Either the assertion indicates an error in the framework itself, or we should provide substantially more information in this error message to help you determine and fix the underlying cause.
In either case, please report this assertion by filing a bug on GitHub:
https://github.com/flutter/flutter/issues/new?template=2_bug.yml
If I change the SizedBox to have a non-zero size, or take the FittedBox out of the Row, then the assertion goes away. I'm only filing this to improve the error message / handling of zero width elements.
Code sample
Code sample
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
useMaterial3: true,
),
home: const Row(
children: [
FittedBox(
child: SizedBox(
height: 0,
width: 0,
),
),
],
),
);
}
}
Screenshots or Video
Screenshots / Video demonstration
[Upload media here]
Logs
Logs
[Paste your logs here]Flutter Doctor output
Doctor output
❯ flutter doctor -v
[✓] Flutter (Channel stable, 3.13.4, on macOS 13.5.2 22G91 darwin-arm64, locale en-GB)
• Flutter version 3.13.4 on channel stable at /opt/homebrew/Caskroom/flutter/3.13.2/flutter
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 367f9ea16b (7 days ago), 2023-09-12 23:27:53 -0500
• Engine revision 9064459a8b
• Dart version 3.1.2
• DevTools version 2.25.0
[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
• Android SDK at /Users/bramp/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+0-17.0.6b829.9-10027231)
• 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 2022.3)
• 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+0-17.0.6b829.9-10027231)
[✓] VS Code (version 1.82.2)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 3.73.20230904
[✓] Connected device (3 available)
• sdk gphone64 arm64 (mobile) • emulator-5554 • android-arm64 • Android 14 (API 34) (emulator)
• macOS (desktop) • macos • darwin-arm64 • macOS 13.5.2 22G91 darwin-arm64
• Chrome (web) • chrome • web-javascript • Google Chrome 116.0.5845.187
[✓] Network resources
• All expected network resources are available.
• No issues found!