Improve Grade output around null safety compiler errors #69022
Description
Running simple Flutter apps with null safety from VSCode or Android Studio triggers a throw in the WidgetInspectorService:
Repro steps
- Create simple null safety app:
flutter create nulltest cd nulltest dart migrate --apply-changes --no-web-preview - Attempt to build APK, forgetting the experiment flag:
flutter build apk
Actual result: A long build exception:
$ flutter build apk
You are building a fat APK that includes binaries for android-arm,
android-arm64, android-x64.
...
lib/main.dart:31:18: Error: This requires the null safety language feature, which is experimental.
You can enable the experiment using the '--enable-experiment=non-nullable' command line option.
MyHomePage({Key? key, this.title}) : super(key: key);
^
lib/main.dart:42:15: Error: This requires the null safety language feature, which is experimental.
You can enable the experiment using the '--enable-experiment=non-nullable' command line option.
final String? title;
^
lib/main.dart:74:33: Error: This requires the null safety language feature, which is experimental.
You can enable the experiment using the '--enable-experiment=non-nullable' command line option.
title: Text(widget.title!),
^
lib/main.dart:101:39: Error: This requires the null safety language feature, which is experimental.
You can enable the experiment using the '--enable-experiment=non-nullable' command line option.
style: Theme.of(context)!.textTheme.headline4,
^
FAILURE: Build failed with an exception.
* Where:
Script '/Users/mit/dev/flutter/packages/flutter_tools/gradle/flutter.gradle' line: 900
* What went wrong:
Execution failed for task ':app:compileFlutterBuildRelease'.
> Process 'command '/Users/mit/dev/flutter/bin/flutter'' finished with non-zero exit value 1
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 24s
Running Gradle task 'assembleRelease'...
Running Gradle task 'assembleRelease'... Done 25.3s
Gradle task assembleRelease failed with exit code 1
Expected result: The error is caught, and a nicely formatted error is printed:
$ flutter build apk
You are building a fat APK that includes binaries for android-arm,
android-arm64, android-x64.
...
Build failed: There are 3 uses of the null safety language feature, which is experimental.
You can enable the experiment using the '--enable-experiment=non-nullable' command line option.
Error details:
lib/main.dart:31:18: Error: This requires the null safety language feature, which is experimental.
MyHomePage({Key? key, this.title}) : super(key: key);
^
lib/main.dart:42:15: Error: This requires the null safety language feature, which is experimental.
final String? title;
^
lib/main.dart:74:33: Error: This requires the null safety language feature, which is experimental.
title: Text(widget.title!),
^
lib/main.dart:101:39: Error: This requires the null safety language feature, which is experimental.
style: Theme.of(context)!.textTheme.headline4,
^
Version information
Flutter 1.24.0-3.0.pre • channel dev • https://github.com/flutter/flutter.git
Framework • revision 2783f8e2e1 (4 days ago) • 2020-10-22 09:36:06 -0700
Engine • revision defa8be2b1
Tools • Dart 2.11.0 (build 2.11.0-242.0.dev)
mit-macbookpro4:nulltest mit$