<p dir="auto">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:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="Running &quot;flutter packages get&quot; in XXX...
The current Flutter SDK version is 0.0.0-unknown.

Because XXX depends on shared_preferences &gt;=0.4.0 which requires Flutter SDK version &gt;=0.1.4 &lt;2.0.0, version solving failed.

pub get failed (1)"><pre class="notranslate"><code class="notranslate">Running "flutter packages get" in XXX...
The current Flutter SDK version is 0.0.0-unknown.

Because XXX depends on shared_preferences &gt;=0.4.0 which requires Flutter SDK version &gt;=0.1.4 &lt;2.0.0, version solving failed.

pub get failed (1)
</code></pre></div>
<p dir="auto">Then I run "flutter doctor -v", and the result is :</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="[✓] 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."><pre class="notranslate"><code class="notranslate">[✓] 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.
</code></pre></div>
<p dir="auto">Why the flutter version is  "v0.0.0-unknown"?</p>
<p dir="auto">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.</p>
<h2 dir="auto">Steps to Reproduce</h2>
<ol dir="auto">
<li>Create a new Flutter project</li>
<li>Enter project</li>
<li>Run <code class="notranslate">flutter test</code> from command line</li>
<li>Tests take 5-6 seconds to run</li>
<li>Compare to Dart1, which was 1-2 seconds</li>
</ol>
<h2 dir="auto">Logs</h2>
<h3 dir="auto">Dart 1</h3>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="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"><pre class="notranslate"><code class="notranslate">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
</code></pre></div>
<h3 dir="auto">Dart 2</h3>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="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"><pre class="notranslate"><code class="notranslate">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
</code></pre></div>
<h2 dir="auto">Flutter Doctor</h2>
<div class="highlight highlight-source-dart notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="[✓] 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!"><pre class="notranslate">[✓] <span class="pl-c1">Flutter</span> (<span class="pl-c1">Channel</span> beta, v0.<span class="pl-c1">1.5</span>, <span class="pl-k">on</span> <span class="pl-c1">Mac</span> <span class="pl-c1">OS</span> <span class="pl-c1">X</span> <span class="pl-c1">10.13</span>.<span class="pl-c1">3</span> 17D102, locale en<span class="pl-k">-</span><span class="pl-c1">US</span>)
    • <span class="pl-c1">Flutter</span> version <span class="pl-c1">0.1</span>.<span class="pl-c1">5</span> at <span class="pl-k">/</span><span class="pl-c1">Users</span><span class="pl-k">/</span>phillywiggins<span class="pl-k">/</span>lab<span class="pl-k">/</span>flutter
    • <span class="pl-c1">Framework</span> revision 3ea4d06340 (<span class="pl-c1">4</span> weeks ago), <span class="pl-c1">2018</span><span class="pl-k">-</span><span class="pl-c1">02</span><span class="pl-k">-</span><span class="pl-c1">22</span> <span class="pl-c1">11</span><span class="pl-k">:</span><span class="pl-c1">12</span><span class="pl-k">:</span><span class="pl-c1">39</span> <span class="pl-k">-</span><span class="pl-c1">0800</span>
    • <span class="pl-c1">Engine</span> revision ead227f118
    • <span class="pl-c1">Dart</span> version <span class="pl-c1">2.0</span>.<span class="pl-c1">0</span><span class="pl-k">-</span>dev.<span class="pl-c1">28.0</span>.flutter<span class="pl-k">-</span>0b4f01f759

[✓] <span class="pl-c1">Android</span> toolchain <span class="pl-k">-</span> develop <span class="pl-k">for</span> <span class="pl-c1">Android</span> devices (<span class="pl-c1">Android</span> <span class="pl-c1">SDK</span> <span class="pl-c1">27.0</span>.<span class="pl-c1">2</span>)
    • <span class="pl-c1">Android</span> <span class="pl-c1">SDK</span> at <span class="pl-k">/</span><span class="pl-c1">Users</span><span class="pl-k">/</span>phillywiggins<span class="pl-k">/</span><span class="pl-c1">Library</span><span class="pl-k">/</span><span class="pl-c1">Android</span><span class="pl-k">/</span>sdk
    • <span class="pl-c1">Android</span> <span class="pl-c1">NDK</span> at <span class="pl-k">/</span><span class="pl-c1">Users</span><span class="pl-k">/</span>phillywiggins<span class="pl-k">/</span><span class="pl-c1">Library</span><span class="pl-k">/</span><span class="pl-c1">Android</span><span class="pl-k">/</span>sdk<span class="pl-k">/</span>ndk<span class="pl-k">-</span>bundle
    • <span class="pl-c1">Platform</span> android<span class="pl-k">-</span><span class="pl-c1">27</span>, build<span class="pl-k">-</span>tools <span class="pl-c1">27.0</span>.<span class="pl-c1">2</span>
    • <span class="pl-c1">ANDROID_HOME</span> <span class="pl-k">=</span> <span class="pl-k">/</span><span class="pl-c1">Users</span><span class="pl-k">/</span>phillywiggins<span class="pl-k">/</span><span class="pl-c1">Library</span><span class="pl-k">/</span><span class="pl-c1">Android</span><span class="pl-k">/</span>sdk
    • <span class="pl-c1">Java</span> binary at<span class="pl-k">:</span> <span class="pl-k">/</span><span class="pl-c1">Applications</span><span class="pl-k">/</span><span class="pl-c1">Android</span> <span class="pl-c1">Studio</span>.app<span class="pl-k">/</span><span class="pl-c1">Contents</span><span class="pl-k">/</span>jre<span class="pl-k">/</span>jdk<span class="pl-k">/</span><span class="pl-c1">Contents</span><span class="pl-k">/</span><span class="pl-c1">Home</span><span class="pl-k">/</span>bin<span class="pl-k">/</span>java
    • <span class="pl-c1">Java</span> version <span class="pl-c1">OpenJDK</span> <span class="pl-c1">Runtime</span> <span class="pl-c1">Environment</span> (build <span class="pl-c1">1.8</span>.0_152<span class="pl-k">-</span>release<span class="pl-k">-</span><span class="pl-c1">915</span><span class="pl-k">-</span>b08)

[✓] iOS toolchain <span class="pl-k">-</span> develop <span class="pl-k">for</span> iOS devices (<span class="pl-c1">Xcode</span> <span class="pl-c1">9.2</span>)
    • <span class="pl-c1">Xcode</span> at <span class="pl-k">/</span><span class="pl-c1">Applications</span><span class="pl-k">/</span><span class="pl-c1">Xcode</span>.app<span class="pl-k">/</span><span class="pl-c1">Contents</span><span class="pl-k">/</span><span class="pl-c1">Developer</span>
    • <span class="pl-c1">Xcode</span> <span class="pl-c1">9.2</span>, <span class="pl-c1">Build</span> version 9C40b
    • ios<span class="pl-k">-</span>deploy <span class="pl-c1">1.9</span>.<span class="pl-c1">2</span>
    • <span class="pl-c1">CocoaPods</span> version <span class="pl-c1">1.3</span>.<span class="pl-c1">1</span>

[✓] <span class="pl-c1">Android</span> <span class="pl-c1">Studio</span> (version <span class="pl-c1">3.0</span>)
    • <span class="pl-c1">Android</span> <span class="pl-c1">Studio</span> at <span class="pl-k">/</span><span class="pl-c1">Applications</span><span class="pl-k">/</span><span class="pl-c1">Android</span> <span class="pl-c1">Studio</span>.app<span class="pl-k">/</span><span class="pl-c1">Contents</span>
    • <span class="pl-c1">Java</span> version <span class="pl-c1">OpenJDK</span> <span class="pl-c1">Runtime</span> <span class="pl-c1">Environment</span> (build <span class="pl-c1">1.8</span>.0_152<span class="pl-k">-</span>release<span class="pl-k">-</span><span class="pl-c1">915</span><span class="pl-k">-</span>b08)

[✓] <span class="pl-c1">IntelliJ</span> <span class="pl-c1">IDEA</span> <span class="pl-c1">Community</span> <span class="pl-c1">Edition</span> (version <span class="pl-c1">2017.3</span>.<span class="pl-c1">5</span>)
    • <span class="pl-c1">Flutter</span> plugin version <span class="pl-c1">22.2</span>.<span class="pl-c1">2</span>
    • <span class="pl-c1">Dart</span> plugin version <span class="pl-c1">173.4548</span>.<span class="pl-c1">30</span>

[✓] <span class="pl-c1">VS</span> <span class="pl-c1">Code</span> (version <span class="pl-c1">1.21</span>.<span class="pl-c1">1</span>)
    • <span class="pl-c1">VS</span> <span class="pl-c1">Code</span> at <span class="pl-k">/</span><span class="pl-c1">Applications</span><span class="pl-k">/</span><span class="pl-c1">Visual</span> <span class="pl-c1">Studio</span> <span class="pl-c1">Code</span>.app<span class="pl-k">/</span><span class="pl-c1">Contents</span>
    • <span class="pl-c1">Dart</span> <span class="pl-c1">Code</span> <span class="pl-k">extension</span> version <span class="pl-c1">2.8</span>.<span class="pl-c1">2</span>

[✓] <span class="pl-c1">Connected</span> devices (<span class="pl-c1">1</span> available)
    • <span class="pl-c1">Android</span> <span class="pl-c1">SDK</span> built <span class="pl-k">for</span> x86 • emulator<span class="pl-k">-</span><span class="pl-c1">5554</span> • android<span class="pl-k">-</span>x86 • <span class="pl-c1">Android</span> <span class="pl-c1">8.0</span>.<span class="pl-c1">0</span> (<span class="pl-c1">API</span> <span class="pl-c1">26</span>) (emulator)

• <span class="pl-c1">No</span> issues found<span class="pl-k">!</span></pre></div>