Debugger expression evaluation only considers first line of multiline expressions for Flutter

[DanTup]

If you evaluate a multi-line expression in Dart, it evaluates the whole multiline expression:

However if you do the same thing in a Flutter app, it only evaluates the first line:

[TahaTesser]

Hi @DanTup
can you please provide your flutter doctor -v?
Thank you

[DanTup]

[✓] Flutter (Channel master, v1.18.0-7.0.pre.47, on Mac OS X 10.15.4 19E287, locale en-GB)
    • Flutter version 1.18.0-7.0.pre.47 at /Users/danny/Dev/Google/flutter
    • Framework revision 240611b05e (4 days ago), 2020-04-23 11:54:02 -0400
    • Engine revision feb94f6c97
    • Dart version 2.9.0 (build 2.9.0-2.0.dev 64b8ded48b)

[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/danny/Library/Android/sdk
    • Platform android-29, build-tools 29.0.2
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b49-5587405)
    • All Android licenses accepted.

[!] Xcode - develop for iOS and macOS (Xcode 11.4.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.4.1, Build version 11E503a
    ✗ CocoaPods not installed.
        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 install:
        sudo gem install cocoapods

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

[✓] Android Studio (version 3.5)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 42.1.1
    • Dart plugin version 191.8593
    • Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b49-5587405)

[✓] VS Code (version 1.44.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.9.1

[✓] Connected device (4 available)
    • iPhone 11 Pro Max • 42F08B32-ABC6-4D33-8D00-7C6D55FFC8AC • ios            • com.apple.CoreSimulator.SimRuntime.iOS-13-4 (simulator)
    • macOS             • macOS                                • darwin-x64     • Mac OS X 10.15.4 19E287
    • Web Server        • web-server                           • web-javascript • Flutter Tools
    • Chrome            • chrome                               • web-javascript • Google Chrome 81.0.4044.122

! Doctor found issues in 1 category.

[DanTup]

I think this might related to how Flutter compiles expressions - seems like it might pass them to Dart, and Dart expects a single line for the expression:

https://github.com/dart-lang/sdk/blob/bd3d08a891791ac3b83a55bd6652ae0b995912e9/pkg/frontend_server/lib/frontend_server.dart#L1198

And Flutter just writes the expression as-is:

flutter/packages/flutter_tools/lib/src/compile.dart

Line 763 in b7e30cf

_server.stdin.writeln(request.expression);

I'm not super familiar with this, @aam might know if this is on the right track.

[aam]

I think this might related to how Flutter compiles expressions - seems like it might pass them to Dart, and Dart expects a single line for the expression:

Yeah, I think you are right!

[HerrNiklasRaab]

Any update on this? Seems like easy to fix?

[yanngasner]

Hi there, anything planned to fix this?
Thx!