Flutter web app sometimes only shows a blank/white page

Hi, Since a few days my vscode debugging (ui click on green arrow) doesn’t work anymore. When I start flutter with chrome the application shows up for milliseconds and then disappears. There are no errors displayed in the logs. When I reload the page in chrome (F5) the application shows up again. When using Android Studio the debugging works as it should. When add --release to the launch.json it works as expected.

Things I have tried and didn’t fix it:

• reverted my code to a month ago to see if it was a code mistake
• reverted flutter vscode extension version to months ago
• deleted vscode cache /Library/Application Support/Code/Cache & /Library/Application Support/Code/CachedData
• reverted flutter to stable 2.2.2
• Created a new flutter application with flutter create but vscode debugs normal
• Switch to flutter master channel

How i fixed it

After downgrading vscode dart extension from 3.24.2 to 3.23.1 it worked again. I guess there must be a problem in the new dart extension version.

Note:

I always had an issue with hot reload since upgrading to null safety months ago. Whenever I try to hot reload(Android studio & vscode), the application disappears and the ios & android simulator goes blank/white screen. Might be connected to this issue might not. I didn’t file an issue for that yet. I have searched a long time for a solution to this but couldn’t find any

flutter analyze

No Issues found

flutter doctor -v

[✓] Flutter (Channel stable, 2.2.3, on macOS 11.4 20F71 darwin-x64, locale de-DE)
    • Flutter version 2.2.3 at /Users/jonaskuschel/Developer/flutter
    • Framework revision f4abaa0735 (vor 6 Tagen), 2021-07-01 12:46:11 -0700
    • Engine revision 241c87ad80
    • Dart version 2.13.4

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.1)
    • Android SDK at /Users/jonaskuschel/Library/Android/sdk
    • Platform android-30, build-tools 30.0.1
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5.1, Build version 12E507
    • CocoaPods version 1.10.1

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

[✓] Android Studio (version 4.2)
    • 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 11.0.8+10-b944.6916264)

[✓] VS Code (version 1.57.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.23.0

[✓] Connected device (1 available)
    • Chrome (web) • chrome • web-javascript • Google Chrome 91.0.4472.114

If you need any more info or logs feel free to ask.

Thank you for your support!

Jonas

[DanTup]

I’m wondering if this might be related to sending the VM Service extension values back at startup. This is something that was “fixed” by #3426 but caused some other issues (like #3454). I’ve changed how this works and wonder if that fixes things for you. Could you try the latest nightly build to see if it’s still an issue?

• Download the nightly-build-vsix archive from the bottom of https://github.com/Dart-Code/Dart-Code/actions/runs/1021916324
• Extract the vsix file out of that archive
• Run the Extension: Install from VSIX command in VS Code
• When prompted, click the Restart/Reload button

If this solves the issue, then I guess it’s already fixed and you can just use that version until the next release. If not, we’ll need to find a way that I can reproduce it, or we’ll have to build something between v3.23 and v3.24 for you to test to see if we can narrow down which change has affected it.

Thanks!

[DanTup]

Great! Thanks for confirming!