<p dir="auto">No known steps to reproduce and unclear whether this actually affects users (since the Flutter app seems to be dead already).</p>
<p dir="auto">The crash collector reported the following stack trace in logcat:</p>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="java.lang.AssertionError
    at io.flutter.view.FlutterView.assertAttached(FlutterView.java:537)
    at io.flutter.view.FlutterView$3.reply(FlutterView.java:679)
    at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler$1.success(MethodChannel.java:194)
    at io.flutter.plugins.googlesignin.GoogleSignInPlugin$Delegate$3.run(GoogleSignInPlugin.java:264)"><pre class="notranslate"><code class="notranslate">java.lang.AssertionError
    at io.flutter.view.FlutterView.assertAttached(FlutterView.java:537)
    at io.flutter.view.FlutterView$3.reply(FlutterView.java:679)
    at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler$1.success(MethodChannel.java:194)
    at io.flutter.plugins.googlesignin.GoogleSignInPlugin$Delegate$3.run(GoogleSignInPlugin.java:264)
</code></pre></div>
<p dir="auto"><a href="https://github.com/flutter/engine/blob/51f12604f7aec7e425be41f56ce8637a948dfa3d/shell/common/engine.cc#L517">https://github.com/flutter/engine/blob/51f12604f7aec7e425be41f56ce8637a948dfa3d/shell/common/engine.cc#L517</a><br>
-&gt; <a href="https://github.com/flutter/engine/blob/51f12604f7aec7e425be41f56ce8637a948dfa3d/shell/platform/android/platform_view_android.cc#L358">https://github.com/flutter/engine/blob/51f12604f7aec7e425be41f56ce8637a948dfa3d/shell/platform/android/platform_view_android.cc#L358</a><br>
-&gt; <a href="https://github.com/flutter/engine/blob/51f12604f7aec7e425be41f56ce8637a948dfa3d/shell/platform/android/io/flutter/view/FlutterView.java#L683">https://github.com/flutter/engine/blob/51f12604f7aec7e425be41f56ce8637a948dfa3d/shell/platform/android/io/flutter/view/FlutterView.java#L683</a></p>
<p dir="auto">That code path can trigger when the flutter view has been detached, which in turn implies that the flutter view has been destroyed by Android.  This was observed in the GoogleSignIn plugin, where the plugin triggers an OEM-widget-based sign-in flow.  The Android OS reserves the right to destroy your view whenever it needs to to free up resources (and will re-create it as necessary), so it's valid for a full-screen sign-in flow to trigger the disposal of your FlutterView (followed by a re-creation when the sign-in completes).</p>