iOS platform view is flashing on top of SliverPersistentHeader

[ilayda-simsek]

Steps to Reproduce

1. Clone the project from https://github.com/ilayda-simsek/flutter-sliver-bug
2. Run the app on an iOS device
3. Scroll up and down
4. Observe that the scrollable platform views in the CustomScrollView are flashing on top of the pinned SliverPersistentHeader and the SliverAppBar widgets

Expected results:

The platform view shouldn't be rendered on top of the pinned headers.

Actual results:

Platform view can be seen on top of the pinned SliverAppBar and the SliverPersistentHeader widgets as user scrolls up and down.
The behavior can be seen in the following video. In here, the SliverAppBar and the SliverPersistentHeader are pinned inside a CustomScrollView. The blue ones are iOS Platform Views. The platform view widget appears briefly on top of the SliverAppBar and the SliverPersistentHeader as user scrolls up and down.

Note: Tried on both stable and master channels. Problem was reproducible in both.

Logs

[✓] Flutter (Channel stable, 2.2.3, on macOS 11.4 20F71 darwin-arm, locale
    en-TR)
    • Flutter version 2.2.3 at /Users/ilaydasimsek/Development/flutter
    • Framework revision f4abaa0735 (3 weeks ago), 2021-07-01 12:46:11 -0700
    • Engine revision 241c87ad80
    • Dart version 2.13.4

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /Users/ilaydasimsek/Library/Android/sdk
    • Platform android-30, build-tools 30.0.3
    • ANDROID_HOME = /Users/ilaydasimsek/Library/Android/sdk
    • Java binary at: /Applications/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5, Build version 12E262
    • CocoaPods version 1.10.1

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

[✓] Android Studio (version 4.2)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)

[✓] Connected device (2 available)
    • iPhone 12 (mobile) • 8EA240E9-5F42-4484-950B-758E90EFDEBF • ios
      • com.apple.CoreSimulator.SimRuntime.iOS-14-5 (simulator)
    • Chrome (web)       • chrome                               • web-javascript
      • Google Chrome 91.0.4472.164

• No issues found!

[TahaTesser]

Hi @ilayda-simsek
Thanks for filing the issue, I can reproduce it

stable	beta	dev	master
❌	❌	❌	❌

Check flutter doctor -v outputs for each channel below

flutter doctor -v

[✓] Flutter (Channel stable, 2.2.3, on macOS 12.0 21A5284e darwin-x64, locale
    en-GB)
    • Flutter version 2.2.3 at /Users/tahatesser/Code/flutter_stable
    • Framework revision f4abaa0735 (3 weeks ago), 2021-07-01 12:46:11 -0700
    • Engine revision 241c87ad80
    • Dart version 2.13.4

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /Users/tahatesser/Code/SDK
    • Platform android-30, build-tools 30.0.3
    • ANDROID_HOME = /Users/tahatesser/Code/SDK
    • Java binary at: /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5.1, Build version 12E507
    • CocoaPods version 1.10.1

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

[✓] Android Studio (version 4.2)
    • Android Studio at /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)

[✓] VS Code (version 1.58.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.24.0

[✓] Connected device (4 available)
    • Taha’s iPhone (mobile) • 00008020-001059882212002E            • ios
      • iOS 14.6
    • iPhone 12 Pro (mobile) • 77C62AB9-8B71-43CF-BCAB-85B0A5B52F85 • ios
      • com.apple.CoreSimulator.SimRuntime.iOS-14-5 (simulator)
    • macOS (desktop)        • macos                                • darwin-x64
      • macOS 12.0 21A5284e darwin-x64
    • Chrome (web)           • chrome                               •
      web-javascript • Google Chrome 92.0.4515.107

• No issues found!

[✓] Flutter (Channel beta, 2.3.0-24.1.pre, on macOS 12.0 21A5284e darwin-x64,
    locale en-GB)
    • Flutter version 2.3.0-24.1.pre at /Users/tahatesser/Code/flutter_beta
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 615957513e (4 weeks ago), 2021-06-25 09:24:44 -0700
    • Engine revision 9d517f475b
    • Dart version 2.14.0 (build 2.14.0-188.5.beta)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /Users/tahatesser/Code/SDK
    • Platform android-30, build-tools 30.0.3
    • ANDROID_HOME = /Users/tahatesser/Code/SDK
    • Java binary at: /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5.1, Build version 12E507
    • CocoaPods version 1.10.1

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

[✓] Android Studio (version 4.2)
    • Android Studio at /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)

[✓] Android Studio (version 4.2)
    • Android Studio at /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)

[✓] VS Code (version 1.58.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.24.0

[✓] Connected device (4 available)
    • Taha’s iPhone (mobile) • 00008020-001059882212002E            • ios
      • iOS 14.6
    • iPhone 12 Pro (mobile) • 77C62AB9-8B71-43CF-BCAB-85B0A5B52F85 • ios
      • com.apple.CoreSimulator.SimRuntime.iOS-14-5 (simulator)
    • macOS (desktop)        • macos                                • darwin-x64
      • macOS 12.0 21A5284e darwin-x64
    • Chrome (web)           • chrome                               •
      web-javascript • Google Chrome 92.0.4515.107

• No issues found!

[✓] Flutter (Channel dev, 2.4.0-4.0.pre, on macOS 12.0 21A5284e darwin-x64,
    locale en-GB)
    • Flutter version 2.4.0-4.0.pre at /Users/tahatesser/Code/flutter_dev
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision cc00e7e6bc (11 days ago), 2021-07-11 18:21:02 -0400
    • Engine revision ed25e8f01e
    • Dart version 2.14.0 (build 2.14.0-301.0.dev)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /Users/tahatesser/Code/SDK
    • Platform android-30, build-tools 30.0.3
    • ANDROID_HOME = /Users/tahatesser/Code/SDK
    • Java binary at: /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5.1, Build version 12E507
    • CocoaPods version 1.10.1

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

[✓] Android Studio (version 4.2)
    • Android Studio at /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)

[✓] Android Studio (version 4.2)
    • Android Studio at /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)

[✓] VS Code (version 1.58.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.24.0

[✓] Connected device (4 available)
    • Taha’s iPhone (mobile) • 00008020-001059882212002E            • ios
      • iOS 14.6 18F72
    • iPhone 12 Pro (mobile) • 77C62AB9-8B71-43CF-BCAB-85B0A5B52F85 • ios
      • com.apple.CoreSimulator.SimRuntime.iOS-14-5 (simulator)
    • macOS (desktop)        • macos                                • darwin-x64
      • macOS 12.0 21A5284e darwin-x64
    • Chrome (web)           • chrome                               •
      web-javascript • Google Chrome 92.0.4515.107

• No issues found!

    darwin-x64, locale en-GB)
    • Flutter version 2.4.0-5.0.pre.145 at /Users/tahatesser/Code/flutter_master
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision ea4589f714 (8 hours ago), 2021-07-22 01:46:04 -0400
    • Engine revision 269082c333
    • Dart version 2.14.0 (build 2.14.0-341.0.dev)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /Users/tahatesser/Code/SDK
    • Platform android-30, build-tools 30.0.3
    • ANDROID_HOME = /Users/tahatesser/Code/SDK
    • Java binary at: /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5.1, Build version 12E507
    • CocoaPods version 1.10.1

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

[✓] Android Studio (version 4.2)
    • Android Studio at /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)

[✓] Android Studio (version 4.2)
    • Android Studio at /Users/tahatesser/Library/Application
      Support/JetBrains/Toolbox/apps/AndroidStudio/ch-0/202.7486908/Android
      Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.8+10-b944.6916264)

[✓] VS Code (version 1.58.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.24.0

[✓] Connected device (4 available)
    • Taha’s iPhone (mobile) • 00008020-001059882212002E            • ios
      • iOS 14.6 18F72
    • iPhone 12 Pro (mobile) • 77C62AB9-8B71-43CF-BCAB-85B0A5B52F85 • ios
      • com.apple.CoreSimulator.SimRuntime.iOS-14-5 (simulator)
    • macOS (desktop)        • macos                                • darwin-x64
      • macOS 12.0 21A5284e darwin-x64
    • Chrome (web)           • chrome                               •
      web-javascript • Google Chrome 92.0.4515.107

• No issues found!

✅ : No Issue ❌: Issue reproduced

[jmagman]

@Piinks Can you give any insight as to whether this is a framework/scrolling or engine issue so we can make sure the right team investigates?