Issue 1:
I upgraded my flutter and there are something wrong with my project: the third libraries can not be found. So I run "flutter packages get", and the result is:

Running "flutter packages get" in XXX...
The current Flutter SDK version is 0.0.0-unknown.

Because XXX depends on shared_preferences >=0.4.0 which requires Flutter SDK version >=0.1.4 <2.0.0, version solving failed.

pub get failed (1)

Then I run "flutter doctor -v", and the result is :

[✓] Flutter (Channel master, v0.0.0-unknown, on Mac OS X 10.13.4 17E199, locale zh-Hans-CN)
• Flutter version 0.0.0-unknown at ***
• Framework revision 2239344597 (17 hours ago), 2018-08-16 16:31:34 +0800
• Engine revision e3687f70c7
• Dart version 2.1.0-dev.0.0.flutter-be6309690f

[!] Android toolchain - develop for Android devices (Android SDK 27.0.3)
• Android SDK at ***
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-27, build-tools 27.0.3
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)
! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses

[✓] iOS toolchain - develop for iOS devices (Xcode 9.4.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 9.4.1, Build version 9F2000
• ios-deploy 1.9.2
• CocoaPods version 1.5.0

[✓] Android Studio (version 3.1)
• Android Studio at /Applications/Android Studio.app/Contents
✗ Flutter plugin not installed; this adds Flutter specific functionality.
✗ Dart plugin not installed; this adds Dart specific functionality.
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)

[✓] VS Code (version 1.26.0)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 2.17.1

[!] Connected devices
! No devices available

! Doctor found issues in 2 categories.

Why the flutter version is "v0.0.0-unknown"?

Issue 2:
Hey there! I've been noticing an interesting problem as I upgrade my libs to Dart 2. I run my tests very often, and have seen them take far longer to start up than in Dart 1. If you're running many iterations of a test trying to fix a bug, it can feel a bit sluggish compared to how fast it was before.

Steps to Reproduce

Create a new Flutter project

Enter project

Run flutter test from command line

Tests take 5-6 seconds to run

Compare to Dart1, which was 1-2 seconds

Logs

Dart 1

gunter lab/slow_tests » time flutter test
00:01 +1: All tests passed!
flutter test 2.02s user 0.36s system 111% cpu 2.125 total
gunter lab/slow_tests » time flutter test
00:01 +1: All tests passed!
flutter test 2.01s user 0.35s system 112% cpu 2.104 total
gunter lab/slow_tests » time flutter test
00:01 +1: All tests passed!
flutter test 2.02s user 0.36s system 112% cpu 2.115 total

Dart 2

gunter lab/slow_tests » time flutter test --preview-dart-2
00:04 +1: All tests passed!
flutter test --preview-dart-2 6.19s user 0.70s system 134% cpu 5.134 total
gunter lab/slow_tests » time flutter test --preview-dart-2
00:04 +1: All tests passed!
flutter test --preview-dart-2 6.26s user 0.68s system 134% cpu 5.163 total
gunter lab/slow_tests » time flutter test --preview-dart-2
00:04 +1: All tests passed!
flutter test --preview-dart-2 6.32s user 0.69s system 134% cpu 5.234 total

Flutter Doctor

[✓] Flutter (Channel beta, v0.1.5, on Mac OS X 10.13.3 17D102, locale en-US)
• Flutter version 0.1.5 at /Users/phillywiggins/lab/flutter
• Framework revision 3ea4d06340 (4 weeks ago), 2018-02-22 11:12:39 -0800
• Engine revision ead227f118
• Dart version 2.0.0-dev.28.0.flutter-0b4f01f759

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.2)
• Android SDK at /Users/phillywiggins/Library/Android/sdk
• Android NDK at /Users/phillywiggins/Library/Android/sdk/ndk-bundle
• Platform android-27, build-tools 27.0.2
• ANDROID_HOME = /Users/phillywiggins/Library/Android/sdk
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] iOS toolchain - develop for iOS devices (Xcode 9.2)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 9.2, Build version 9C40b
• ios-deploy 1.9.2
• CocoaPods version 1.3.1

[✓] Android Studio (version 3.0)
• Android Studio at /Applications/Android Studio.app/Contents
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b08)

[✓] IntelliJ IDEA Community Edition (version 2017.3.5)
• Flutter plugin version 22.2.2
• Dart plugin version 173.4548.30

[✓] VS Code (version 1.21.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Dart Code extension version 2.8.2

[✓] Connected devices (1 available)
• Android SDK built for x86 • emulator-5554 • android-x86 • Android 8.0.0 (API 26) (emulator)

• No issues found!