FMorschel · GitHub

Describe the bug
Flutter Widget Preview is retrying forever when problem occurs.

To Reproduce
Steps to reproduce the behavior:
I'm not sure how to repro in any machine yet, but I' getting:

Dart Code extension: 3.131.20260324
Flutter extension: 3.131.20260303 (activated)
App: Visual Studio Code
App Host: desktop
Version: win 1.113.0
Logging Categories:
    FlutterWidgetPreview
Mon Mar 30 2026 [14:19:45 GMT-0300 (Horário Padrão de Brasília)] Log file started
[14:20:09] <== [{"event":"widget_preview.initializing","params":{"pid":2604}}]
[14:20:09] <== [{"event":"widget_preview.logMessage","params":{"level":"warning","message":"Invalid Widget Preview Scaffold manifest at C:\\TMP\\flutter_tools.6e737b4c\\widget_preview_scaffold4a9cbc58\\preview_manifest.json. Regenerating Widget Preview Scaffold."}}]
[14:20:09] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Creating widget preview scaffolding at: C:\\TMP\\flutter_tools.6e737b4c\\widget_preview_scaffold4a9cbc58"}}]
[14:20:10] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Creating the Widget Preview Scaffold manifest at C:\\TMP\\flutter_tools.6e737b4c\\widget_preview_scaffold4a9cbc58\\preview_manifest.json"}}]
[14:20:12] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Finding previews in C:\\Fontes\\_local\\Flutter\\new_project..."}}]
[14:20:31] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Found 18 previews."}}]
[14:20:31] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Launching the Widget Preview Scaffold on Web Server..."}}]
[14:20:31] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Launching lib\\main.dart on Web Server in debug mode..."}}]
[14:20:34] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Waiting for connection from debug service on Web Server..."}}]
[14:20:34] <== [{"event":"widget_preview.logMessage","params":{"level":"error","message":"Error: SDK root directory not found: /C:/Users/felipe-m/.puro/envs/stable/flutter/bin/cache/flutter_web_sdk/."}}]
[14:20:59] <== [{"event":"widget_preview.logMessage","params":{"level":"error","message":"Failed to compile application."}}]
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Detected change in C:\\Fontes\\_local\\Flutter\\new_project\\test\\widgets\\multi_options_input_widget_test.dart."}}]
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Finding previews in C:\\Fontes\\_local\\Flutter\\new_project\\test\\widgets\\multi_options_input_widget_test.dart..."}}]
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Found 0 previews."}}]
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Updated previews for file:///C:/Fontes/_local/Flutter/new_project/test/widgets/multi_options_input_widget_test.dart: []"}}]
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Triggering reload based on change to preview set: {(path: C:\\Fontes\\_local\\Flutter\\new_project\\lib\\main.dart, uri: package:new_project/main.dart): (<snip>
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Performing hot reload..."}}]
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Waiting for connection from debug service on Web Server..."}}]
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"error","message":"Null check operator used on a null value"}}]
[14:21:08] <== [{"event":"widget_preview.logMessage","params":{"level":"error","message":"Error: SDK root directory not found: /C:/Users/felipe-m/.puro/envs/stable/flutter/bin/cache/flutter_web_sdk/."}}]
[14:21:13] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Detected change in C:\\Fontes\\_local\\Flutter\\new_project\\test\\widgets\\multi_options_input_widget_test.dart."}}]
[14:21:13] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Finding previews in C:\\Fontes\\_local\\Flutter\\new_project\\test\\widgets\\multi_options_input_widget_test.dart..."}}]
[14:21:13] <== [{"event":"widget_preview.logMessage","params":{"level":"status","message":"Found 0 previews."}}]

flutterWidgetPreview.log

Expected behavior
For the extension to give up and show the log file.

Screenshots

Image

Please complete the following information:

Workspace Environment 
Dart Code extension: 3.131.20260324
Flutter extension: 3.131.20260303 (activated)
App: Visual Studio Code
App Host: desktop
Version: win 1.113.0
Workspace type: Flutter (LSP)
Workspace name: new_project
Dart (3.11.3): C:\Users\felipe-m\.puro\shared\caches\052f31d115eceda8cbff1b3481fcde4330c4ae12\dart-sdk
Flutter (3.41.5): C:\Users\felipe-m\.puro\envs\stable\flutter (No device)
Output from 'dart info'

C:\Users\felipe-m\.puro\shared\caches\052f31d115eceda8cbff1b3481fcde4330c4ae12\dart-sdk\bin\dart.exe info

If providing this information as part of reporting a bug, please review the information
below to ensure it only contains things you're comfortable posting publicly.

General info

  • Dart 3.11.3 (stable) (Tue Mar 17 01:06:16 2026 -0700) on "windows_x64"
  • on windows / "Windows 11 Pro" 10.0 (Build 26200)
  • locale is pt-BR

Project info

  • sdk constraint: '^3.10.8'
  • dependencies: flutter, json_annotation, path, path_provider
  • dev_dependencies: build_runner, flutter_test, json_serializable

Process info

Memory CPU Elapsed time Command line
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dart.exe
0 MB -- dartvm.exe
0 MB -- dartvm.exe
0 MB -- dartvm.exe
0 MB -- dartvm.exe
0 MB -- dartvm.exe
0 MB -- dartvm.exe
Output from 'flutter doctor'

C:\Users\felipe-m\.puro\envs\stable\flutter\bin\flutter.bat doctor -v

[√] Flutter (Channel stable, 3.41.5, on Microsoft Windows [versão 10.0.26200.8037], locale pt-BR) [1.363ms]
    • Flutter version 3.41.5 on channel stable at C:\Users\felipe-m\.puro\envs\stable\flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 2c9eb20739 (13 days ago), 2026-03-17 16:14:01 -0700
    • Engine revision 052f31d115
    • Dart version 3.11.3
    • DevTools version 2.54.2
    • Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations, enable-native-assets, omit-legacy-version-file, enable-lldb-debugging, enable-uiscene-migration
[√] Windows Version (Windows 11 or higher, 25H2, 2009) [1.522ms]
[√] Android toolchain - develop for Android devices (Android SDK version 36.1.0) [3,4s]
    • Android SDK at C:\AndroidStudioSdk
    • Emulator version 36.4.10.0 (build_id 15004761) (CL:N/A)
    • Platform android-36.1, build-tools 36.1.0
    • ANDROID_HOME = C:\AndroidStudioSdk
    • Java binary at: C:\RECH\zulu17.0.18\x64\bin\java
      This JDK is specified in your Flutter configuration.
      To change the current JDK, run: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version OpenJDK Runtime Environment Zulu17.64+17-CA (build 17.0.18+8-LTS)
    • All Android licenses accepted.
[√] Chrome - develop for the web [154ms]
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe
[√] Visual Studio - develop Windows apps (Visual Studio Community 2026 18.4.2) [152ms]
    • Visual Studio at C:\Program Files\Microsoft Visual Studio\18\Community
    • Visual Studio Community 2026 version 18.4.11620.152
    • Windows 10 SDK version 10.0.26100.0
[√] Connected device (4 available) [557ms]
    • sdk gphone64 x86 64 (mobile) • emulator-5554 • android-x64    • Android 16 (API 36) (emulator)
    • Windows (desktop)            • windows       • windows-x64    • Microsoft Windows [versão 10.0.26200.8037]
    • Chrome (web)                 • chrome        • web-javascript • Google Chrome 146.0.7680.165
    • Edge (web)                   • edge          • web-javascript • Microsoft Edge 146.0.3856.84
[√] Network resources [474ms]
    • All expected network resources are available.
• No issues found!

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