Assertion error when using FittedBox (BoxFit.scaleDown,) inside AspectRatio within a Container with fixed width about flutter

[danagbemava-nc]

I can't say why it disappears with device_preview but the assert is weird.

You may file an issue with the device_preview package maintainers so that it can be investigated.

Labeling for further investigation.

complete code sample

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  const MyHomePage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Center(
        child: Column(
          children: [
            SizedBox(
              width: MediaQuery.sizeOf(context).width * 0.3,
              child: const AspectRatio(
                aspectRatio: 16 / 9,
                child: FittedBox(
                  fit: BoxFit.scaleDown,
                  child: Image(
                    image: NetworkImage(
                      'https://www.figma.com/file/8WJqutydnwMKD9P1K2o0sQ/image/8af266d840515558d8a8420841ad055b07310ae4',
                    ),
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

flutter doctor -v

[✓] Flutter (Channel stable, 3.16.9, on macOS 14.3 23D56 darwin-arm64, locale en-GB)
    • Flutter version 3.16.9 on channel stable at /Users/nexus/dev/sdks/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 41456452f2 (13 days ago), 2024-01-25 10:06:23 -0800
    • Engine revision f40e976bed
    • Dart version 3.2.6
    • DevTools version 2.28.5

[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
    • Android SDK at /Users/nexus/Library/Android/sdk
    • Platform android-34, build-tools 34.0.0
    • Java binary at: /Users/nexus/Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.7+0-17.0.7b1000.6-10550314)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 15.2)
    • Xcode at /Applications/Xcode-15.2.0.app/Contents/Developer
    • Build 15C500b
    • CocoaPods version 1.14.3

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2023.1)
    • Android Studio at /Users/nexus/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 17.0.7+0-17.0.7b1000.6-10550314)

[✓] IntelliJ IDEA Ultimate Edition (version 2023.2.5)
    • IntelliJ at /Users/nexus/Applications/IntelliJ IDEA Ultimate.app
    • Flutter plugin version 76.3.4
    • Dart plugin version 232.10072.19

[✓] VS Code (version 1.86.0)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.82.0

[✓] Connected device (2 available)
    • macOS (desktop) • macos  • darwin-arm64   • macOS 14.3 23D56 darwin-arm64
    • Chrome (web)    • chrome • web-javascript • Google Chrome 121.0.6167.139
    ! Error: Browsing on the local area network for Dean’s iPad. Ensure the device is unlocked and attached with a cable or associated with the same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)
    ! Error: Browsing on the local area network for Nexus. Ensure the device is unlocked and attached with a cable or associated with the same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)

[✓] Network resources
    • All expected network resources are available.

• No issues found!

[!] Flutter (Channel master, 3.20.0-3.0.pre.19, on macOS 14.3 23D56 darwin-arm64, locale en-GB)
    • Flutter version 3.20.0-3.0.pre.19 on channel master at /Users/nexus/dev/sdks/flutters
    ! Warning: `flutter` on your path resolves to /Users/nexus/dev/sdks/flutter/bin/flutter, which is not inside your current Flutter SDK checkout at /Users/nexus/dev/sdks/flutters. Consider adding /Users/nexus/dev/sdks/flutters/bin to the front of your path.
    ! Warning: `dart` on your path resolves to /Users/nexus/dev/sdks/flutter/bin/dart, which is not inside your current Flutter SDK checkout at /Users/nexus/dev/sdks/flutters. Consider adding /Users/nexus/dev/sdks/flutters/bin to the front of your path.
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision db141ecd28 (4 hours ago), 2024-02-06 20:00:08 -0800
    • Engine revision 808886312e
    • Dart version 3.4.0 (build 3.4.0-104.0.dev)
    • DevTools version 2.32.0
    • If those were intentional, you can disregard the above warnings; however it is recommended to use "git" directly to perform update checks and upgrades.

[✓] Android toolchain - develop for Android devices (Android SDK version 34.0.0)
    • Android SDK at /Users/nexus/Library/Android/sdk
    • Platform android-34, build-tools 34.0.0
    • Java binary at: /Users/nexus/Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.7+0-17.0.7b1000.6-10550314)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 15.2)
    • Xcode at /Applications/Xcode-15.2.0.app/Contents/Developer
    • Build 15C500b
    • CocoaPods version 1.14.3

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2023.1)
    • Android Studio at /Users/nexus/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 17.0.7+0-17.0.7b1000.6-10550314)

[✓] IntelliJ IDEA Ultimate Edition (version 2023.2.5)
    • IntelliJ at /Users/nexus/Applications/IntelliJ IDEA Ultimate.app
    • Flutter plugin version 76.3.4
    • Dart plugin version 232.10072.19

[✓] VS Code (version 1.86.0)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.82.0

[✓] Connected device (3 available)
    • macOS (desktop)                 • macos                 • darwin-arm64   • macOS 14.3 23D56 darwin-arm64
    • Mac Designed for iPad (desktop) • mac-designed-for-ipad • darwin         • macOS 14.3 23D56 darwin-arm64
    • Chrome (web)                    • chrome                • web-javascript • Google Chrome 121.0.6167.139
    ! Error: Browsing on the local area network for Dean’s iPad. Ensure the device is unlocked and attached with a cable or associated with the same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)
    ! Error: Browsing on the local area network for Nexus. Ensure the device is unlocked and attached with a cable or associated with the same local area network as this Mac.
      The device must be opted into Developer Mode to connect wirelessly. (code -27)

[✓] Network resources
    • All expected network resources are available.

! Doctor found issues in 1 category.

[danagbemava-nc]

Hi @Osama-Al-Fawaz, I'm curious, if you do not use the device_preview widget, are you able to see the image? While reproducing this, although I got the assertion error, the image was visible on my device.

[Osama-Al-Fawaz]

hey @danagbemava-nc , you are right. when i didn't use device_preview the image did not disappear but i got the assertion error just like you.
i think its weird that it asserts width > 0.0 even when i give a fixed width. its also weird that it disappears with device_preview but this may or may not be the package creators problem