Pasting into TextField in Text Fields demo in Gallery doesn't work on iOS

[alardizabal]

On iOS, pasting into a text field doesn't work. The validator returns that the field is empty.

[✓] Flutter (on Mac OS X 10.12.6 16G29, locale en-US, channel master)
    • Flutter at /Users/albertlardizabal/dev/flutter
    • Framework revision 60d9479110 (11 minutes ago), 2017-08-17 19:23:59 -0400
    • Engine revision a246501917
    • Tools Dart version 1.25.0-dev.11.0

[✓] Android toolchain - develop for Android devices (Android SDK 26.0.0)
    • Android SDK at /Users/albertlardizabal/Library/Android/sdk
    • Platform android-26, build-tools 26.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[✓] iOS toolchain - develop for iOS devices (Xcode 8.3.3)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 8.3.3, Build version 8E3004b
    • ios-deploy 1.9.0
    • CocoaPods version 1.2.1

[✓] Android Studio
    • Android Studio at /Applications/Android Studio 3.0 Preview.app/Contents
    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-915-b01)

[✓] Android Studio (version 2.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Java version OpenJDK Runtime Environment (build 1.8.0_112-release-b06)

[✓] IntelliJ IDEA Community Edition (version 2017.2.2)
    • Flutter plugin version 16.0
    • Dart plugin version 172.3757.32

[✓] Connected devices
    • Posse iPhone 6s • ac24c3de3cbe39efed542095769ce83fc89630f7 • ios • iOS 10.3.3

[eseidelGoogle]

This shows up in the Hamilton App as well. @cbracken can you take a look?

[cbracken]

Will do!

[cbracken]

Quick update: looks like this isn't password-specific. I get the same behaviour when pasting into a field with obscureText: false.

[cbracken]

Looks like TextSelectionControls.handlePaste never triggers an update to the underlying text field value within the framework.

As is, handlePaste calls updates its delegate overlay by setting TextSelectionOverlay.textEditingValue to the new value, which updates the EditableText underlying the textField in _handleSelectionOverlayChanged; however, we never call widget.onChanged in this case. In the case of a form field, that means the form's onChanged is never triggered.

So why does this work on Android? When the underlying state changes in EditableText, we push an update to the engine. On Android, a change to the text triggers a restartInput call on the input manager, which results in the engine is firing an TextInputClient.updateEditingState message back into the framework, which triggers the necessary updates to the text field contents; on iOS, the engine isn't firing this update back, on the assumption that if the framework requested an update, it already knows about it.

[cbracken]

Got a two-line patch to fix this. Banging up a test first.

[cbracken]

Fix rolled into framework in #11707