Flutter tool crashes when you type Ctrl-\ #58391

Activity

1. Hixie

   added

   c: crashStack traces logged to the consoleStack traces logged to the console

   toolAffects the "flutter" command-line tool. See also t: labels.Affects the "flutter" command-line tool. See also t: labels.

   a: qualityA truly polished experienceA truly polished experience

   P2Important issues not at the top of the work listImportant issues not at the top of the work list

   on May 31, 2020
2. jason-simmons commented on Jun 2, 2020

   

   jason-simmons

   on Jun 2, 2020

   Member

   More actions

   Ctrl-\ sends a SIGQUIT to child processes. The Dart SDK provides a SIGQUIT handler that starts up or shuts down the VM service. The handler also prints an "Observatory listening" or "Observatory no longer listening" message.

   This works as expected when I use flutter run. What are you seeing when flutter run crashes in your environment? Does the tool dump a stack trace?

   Ctrl-\ does crash the tool when I run flutter analyze --watch. flutter analyze --watch is starting an analysis server child process that writes JSON messages on its stdout. Pressing ctrl-\ causes the child process to write the "Observatory listening" message to stdout. The tool then tries to parse this as JSON and throws.

   The VM service apparently supports a SILENT_OBSERVATORY property that will disable the observatory messages (https://github.com/dart-lang/sdk/blob/master/sdk/lib/_internal/vm/bin/vmservice_server.dart#L9).

   The tool could pass this flag to the analysis server command line. Or it could just skip any lines in the analysis server's output that do not parse as valid JSON.
3. Hixie commented on Jan 21, 2021

   

   Hixie

   on Jan 21, 2021

   ContributorAuthor

   More actions

   Yeah I can only repro this for the analysis case.
4. darshankawar commented on Apr 14, 2021

   

   darshankawar

   on Apr 14, 2021

   Member

   More actions

   Replicable using latest stable version.

   dhs@Dhss-MacBook-Pro macbug % flutter analyze --watch
   Analyzing /Users/dhs/Documents/NCFlutter/macbug...                  55ms
      info • Avoid using web-only libraries outside Flutter web plugin packages • lib/main.dart:1:1 • avoid_web_libraries_in_flutter
      info • Unused import: 'package:macbug/main.dart' • test/widget_test.dart:11:8 • unused_import
     error • The function 'MyApp' isn't defined • test/widget_test.dart:16:29 • undefined_function
   3 issues found. (3 new) • analyzed 3 files (ran in 0.07s)
   ^\Observatory listening on http://127.0.0.1:52358/0CzJP3IwqJU=/
   
   Oops; flutter has exited unexpectedly: "FormatException: Unexpected character (at character 1)
   Observatory listening on http://127.0.0.1:52359/QVxc9lynYEk=/
   ^
   ".
   A crash report has been written to /Users/dhs/Documents/NCFlutter/macbug/flutter_01.log.
   This crash may already be reported. Check GitHub for similar crashes.
   https://github.com/flutter/flutter/issues?q=is%3Aissue+FormatException%3A+Unexpected+character+%28at+character+1%29%0AObservatory+listening+on+http%3A%2F%2F127.0.0.1%3A52359%2FQVxc9lynYEk%3D%2F%0A%5E%0A
   
   To report your crash to the Flutter team, first read the guide to filing a bug.
   https://flutter.dev/docs/resources/bug-reports
   
   Create a new GitHub issue by pasting this link into your browser and completing the issue template. Thank you!
   https://git.io/JOsRT
   
   dhs@Dhss-MacBook-Pro macbug % 
   
   

   flutter doctor -v

   [✓] Flutter (Channel stable, 2.0.4, on Mac OS X 10.15.4 19E2269 darwin-x64,
       locale en-GB)
       • Flutter version 2.0.4 at /Users/dhs/documents/fluttersdk/flutter
       • Framework revision b1395592de (7 days ago), 2021-04-01 14:25:01 -0700
       • Engine revision 2dce47073a
       • Dart version 2.12.2
   
   [!] Xcode - develop for iOS and macOS
       • Xcode at /Applications/Xcode.app/Contents/Developer
       • Xcode 12.3, Build version 12C33
       ! CocoaPods 1.9.3 out of date (1.10.0 is recommended).
           CocoaPods is used to retrieve the iOS and macOS platform side's plugin
           code that responds to your plugin usage on the Dart side.
           Without CocoaPods, plugins will not work on iOS or macOS.
           For more info, see https://flutter.dev/platform-plugins
         To upgrade see
         https://guides.cocoapods.org/using/getting-started.html#installation for
         instructions.
   
   [✓] Chrome - develop for the web
       • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome
   [✓] Android Studio (version 4.1)
       • 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
         1.8.0_242-release-1644-b3-6915495)    
   
   [✓] VS Code (version 1.55.0)
       • VS Code at /Applications/Visual Studio Code.app/Contents
       • Flutter extension version 3.20.0
   
   [✓] Connected device (3 available)
       • SM A260G (mobile)            • 5200763ebcfa861f • android-arm    • Android
         8.1.0 (API 27)
       • Darshan's iphone (mobile) • 21150b119064aecc249dfcfe05e259197461ce23 • ios
         • iOS 14.4.1
       • macOS (desktop)           • macos                                    •
         darwin-x64     • Mac OS X 10.15.4 19E2269 darwin-x64
       • Chrome (web)              • chrome                                   •
         web-javascript • Google Chrome 89.0.4389.114
   
   ! Doctor found issues in 1 category.
   
   
5. darshankawar

   added

   found in release: 2.0Found to occur in 2.0Found to occur in 2.0

   has reproducible stepsThe issue has been confirmed reproducible and is ready to work onThe issue has been confirmed reproducible and is ready to work on

   on Apr 14, 2021
6. dam-ease commented on May 9, 2023

   

   dam-ease

   on May 9, 2023

   More actions

   I am able to reproduce this issue on the latest master and stable channels.

   Details

   Oops; flutter has exited unexpectedly: "FormatException: Unexpected character (at character 1)
   The Dart VM service is listening on http://127.0.0.1:50245/vBMtGcJD6io=/
   ^
   ".
   Oops; flutter has exited unexpectedly: "FormatException: Unexpected character (at character 1)
   The Dart VM service is listening on http://127.0.0.1:50245/vBMtGcJD6io=/
   ^
   ".
   A crash report has been written to /Users/dammya/triage/flutter_master/flutter_01.log.
   This crash may already be reported. Check GitHub for similar crashes.
   https://github.com/flutter/flutter/issues?q=is%3Aissue+FormatException%3A+Unexpected+character+%28at+character+1%29%0AThe+Dart+VM+service+is+listening+on+http%3A%2F%2F127.0.0.1%3A49999%2FrXEN7QEU3b4%3D%2F%0A%5E%0A
   
   To report your crash to the Flutter team, first read the guide to filing a bug.
   https://flutter.dev/docs/resources/bug-reports
   
   Create a new GitHub issue by pasting this link into your browser and completing the issue template. Thank you!
   https://github.com/flutter/flutter/issues/new?title=%5Btool_crash%5D+FormatException&body=%23%23+Command%0A%60%60%60%0Aflutter+analyze+--watch%0A%60%60%60%0A%0A%23%23+Steps+to+Reproduce%0A1.+...%0A2.+...%0A3.+...%0A%0A%23%23+Logs%0AFormatException%0A%60%60%60%0A%230++++++_ChunkedJsonParser.fail+%28dart%3Aconvert-patch%2Fconvert_patch.dart%3A1383%3A5%29%0A%231++++++_ChunkedJsonParser.parseNumber+%28dart%3Aconvert-patch%2Fconvert_patch.dart%3A1250%3A9%29%0A%232++++++_ChunkedJsonParser.parse+%28dart%3Aconvert-patch%2Fconvert_patch.dart%3A915%3A22%29%0A%233++++++_parseJson+%28dart%3Aconvert-patch%2Fconvert_patch.dart%3A35%3A10%29%0A%234++++++JsonDecoder.convert+%28dart%3Aconvert%2Fjson.dart%3A610%3A36%29%0A%235++++++JsonCodec.decode+%28dart%3Aconvert%2Fjson.dart%3A216%3A41%29%0A%236++++++AnalysisServer._handleServerResponse+%28package%3Aflutter_tools%2Fsrc%2Fdart%2Fanalysis.dart%3A140%3A35%29%0A%237++++++_rootRunUnary+%28dart%3Aasync%2Fzone.dart%3A1406%3A47%29%0A%238++++++_CustomZone.runUnary+%28dart%3Aasync%2Fzone.dart%3A1307%3A19%29%0A%239++++++_CustomZone.runUnaryGuarded+%28dart%3Aasync%2Fzone.dart%3A1216%3A7%29%0A%2310+++++_BufferingStreamSubscription._sendData+%28dart%3Aasync%2Fstream_impl.dart%3A339%3A11%29%0A%2311+++++_BufferingStreamSubscription._add+%28dart%3Aasync%2Fstream_impl.dart%3A271%3A7%29%0A%2312+++++_SinkTransformerStreamSubscription._add+%28dart%3Aasync%2Fstream_transformers.dart%3A63%3A11%29%0A%2313+++++_EventSinkWrapper.add+%28dart%3Aasync%2Fstream_transformers.dart%3A13%3A11%29%0A%2314+++++_StringAdapterSink.add+%28dart%3Aconvert%2Fstring_conversion.dart%3A238%3A11%29%0A%2315+++++_LineSplitterSink._addLines+%28dart%3Aconvert%2Fline_splitter.dart%3A153%3A13%29%0A%2316+++++_LineSplitterSink.addSlice+%28dart%3Aconvert%2Fline_splitter.dart%3A128%3A5%29%0A%2317+++++StringConversionSinkMixin.add+%28dart%3Aconvert%2Fstring_conversion.dart%3A163%3A5%29%0A%2318+++++_SinkTransformerStreamSubscription._handleData+%28dart%3Aasync%2Fstream_transformers.dart%3A111%3A24%29%0A%2319+++++_rootRunUnary+%28dart%3Aasync%2Fzone.dart%3A1406%3A47%29%0A%2320+++++_CustomZone.runUnary+%28dart%3Aasync%2Fzone.dart%3A1307%3A19%29%0A%2321+++++_CustomZone.runUnaryGuarded+%28dart%3Aasync%2Fzone.dart%3A1216%3A7%29%0A%2322+++++_BufferingStreamSubscription._sendData+%28dart%3Aasync%2Fstream_impl.dart%3A339%3A11%29%0A%2323+++++_BufferingStreamSubscription._add+%28dart%3Aasync%2Fstream_impl.dart%3A271%3A7%29%0A%2324+++++_SinkTransformerStreamSubscription._add+%28dart%3Aasync%2Fstream_transformers.dart%3A63%3A11%29%0A%60%60%60%0A%60%60%60%0A%1B%5B32m%5B%E2%9C%93%5D%1B%5B39m+Flutter+%28Channel+stable%2C+3.7.12%2C+on+macOS+13.3+22E252+darwin-arm64%2C+locale+en-NG%29%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Flutter+version+3.7.12+on+channel+stable+at+%2FUsers%2Fdammya%2Fsdks%2Fflutter%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Upstream+repository+https%3A%2F%2Fgithub.com%2Fflutter%2Fflutter.git%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Framework+revision+4d9e56e694+%283+weeks+ago%29%2C+2023-04-17+21%3A47%3A46+-0400%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Engine+revision+1a65d409c7%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Dart+version+2.19.6%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+DevTools+version+2.20.1%0A%0A%1B%5B32m%5B%E2%9C%93%5D%1B%5B39m+Android+toolchain+-+develop+for+Android+devices+%28Android+SDK+version+32.1.0-rc1%29%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Android+SDK+at+%2FUsers%2Fdammya%2FLibrary%2FAndroid%2Fsdk%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Platform+android-33%2C+build-tools+32.1.0-rc1%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+ANDROID_HOME+%3D+%2FUsers%2Fdammya%2FLibrary%2FAndroid%2Fsdk%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Java+binary+at%3A+%2FApplications%2FAndroid+Studio.app%2FContents%2Fjre%2FContents%2FHome%2Fbin%2Fjava%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Java+version+OpenJDK+Runtime+Environment+%28build+11.0.12%2B0-b1504.28-7817840%29%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+All+Android+licenses+accepted.%0A%0A%1B%5B32m%5B%E2%9C%93%5D%1B%5B39m+Xcode+-+develop+for+iOS+and+macOS+%28Xcode+14.3%29%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Xcode+at+%2FApplications%2FXcode.app%2FContents%2FDeveloper%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Build+14E222b%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+CocoaPods+version+1.11.3%0A%0A%1B%5B32m%5B%E2%9C%93%5D%1B%5B39m+Chrome+-+develop+for+the+web%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Chrome+at+%2FApplications%2FGoogle+Chrome.app%2FContents%2FMacOS%2FGoogle+Chrome%0A%0A%1B%5B32m%5B%E2%9C%93%5D%1B%5B39m+Android+Studio+%28version+2021.2%29%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Android+Studio+at+%2FApplications%2FAndroid+Studio.app%2FContents%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Flutter+plugin+can+be+installed+from%3A%0A++++++%F0%9F%94%A8+https%3A%2F%2Fplugins.jetbrains.com%2Fplugin%2F9212-flutter%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Dart+plugin+can+be+installed+from%3A%0A++++++%F0%9F%94%A8+https%3A%2F%2Fplugins.jetbrains.com%2Fplugin%2F6351-dart%0A++++%1B%5B32m%E2%80%A2%1B%5B39m+Java+version+OpenJDK+Runtime+Environment+%28build+11.0.12%2B0-b1504.28-7817840%29%0A%0A%1B%5B32m%5B%E2%9C%9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  
7. dam-ease

   added

   found in release: 3.7Found to occur in 3.7Found to occur in 3.7

   found in release: 3.11Found to occur in 3.11Found to occur in 3.11

   and removed

   found in release: 2.0Found to occur in 2.0Found to occur in 2.0

   on May 9, 2023
8. flutter-triage-bot

   added

   team-toolOwned by Flutter Tool teamOwned by Flutter Tool team

   triaged-toolTriaged by Flutter Tool teamTriaged by Flutter Tool team

   on Jul 8, 2023
9. bkonyi

   added a commit that references this issue on Jul 7, 2025

   [ Tool ] Fix crash when SIGQUIT is sent to enable the VM service for …

   ...

   5b85eb3
10. bkonyi

    self-assigned this

    on Jul 7, 2025
11. github-merge-queue

    added a commit that references this issue on Jul 7, 2025

    [ Tool ] Fix crash when SIGQUIT is sent to enable the VM service for …

    ...

    9de6f68
12. auto-submit

    closed this as completedin #171713on Jul 7, 2025
13. darshankawar

    added

    r: fixedIssue is closed as already fixed in a newer versionIssue is closed as already fixed in a newer version

    on Jul 8, 2025
14. mboetger

    added a commit that references this issue on Jul 21, 2025

    [ Tool ] Fix crash when SIGQUIT is sent to enable the VM service for …

    ...

    7eda82d
15. github-actions commented on Jul 22, 2025

    

    github-actionsbot

    on Jul 22, 2025 – with GitHub Actions

    More actions

    This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.
16. github-actions

    locked as resolved and limited conversation to collaborators on Jul 22, 2025
17. azatech

    added a commit that references this issue on Jul 28, 2025

    [ Tool ] Fix crash when SIGQUIT is sent to enable the VM service for …

    ...

    9486b49
18. lucaantonelli

    added a commit that references this issue on Nov 21, 2025

    [ Tool ] Fix crash when SIGQUIT is sent to enable the VM service for …

    ...

    2e0b3c0
19. Nakiha

    added a commit that references this issue on Sep 28, 2026

    [ Tool ] Fix crash when SIGQUIT is sent to enable the VM service for …

    ...

    fb3da1f