iOS: Multiline TextInput onKeyPress event handler unexpectedly receives a Backspace event

Description

The TextInput onKeyPress event handler receives an unexpected Backspace event when multiline is true. The exact behavior varies between iOS 15 and iOS 16:

• iOS 15: The Backspace event is received after value is reset to an empty string
• iOS 16: The Backspace event is received on EVERY change AND when value is reset to an empty string

This has been tested on iOS 15.5, 16.4, and 16.5.

Possibly related: https://github.com/facebook/react-native/issues/34891

React Native Version

0.71.11

Output of npx react-native info

System:
OS: macOS 13.4
CPU: (16) x64 Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz
Memory: 27.38 GB / 64.00 GB
Shell: 5.9 - /usr/local/bin/zsh
Binaries:
Node: 18.16.0 - ~/.asdf/installs/nodejs/18.16.0/bin/node
Yarn: 1.22.19 - /usr/local/bin/yarn
npm: 9.6.6 - ~/.asdf/plugins/nodejs/shims/npm
Watchman: Not Found
Managers:
CocoaPods: 1.12.1 - /Users/jeff/.asdf/shims/pod
SDKs:
iOS SDK:
Platforms: DriverKit 22.4, iOS 16.4, macOS 13.3, tvOS 16.4, watchOS 9.4
Android SDK: Not Found
IDEs:
Android Studio: 2022.2 AI-222.4459.24.2221.10121639
Xcode: 14.3.1/14E300c - /usr/bin/xcodebuild
Languages:
Java: 11.0.13 - /Users/jeff/.asdf/shims/javac
npmPackages:
@react-native-community/cli: Not Found
react: 18.2.0 => 18.2.0
react-native: 0.71.11 => 0.71.11
react-native-macos: Not Found
npmGlobalPackages:
react-native: Not Found

Steps to reproduce

1. Add a <TextInput multiline /> component and log all events received by onKeyPress
2. Type into the input
3. Observe that an event with nativeEvent.key set to 'Backspace' is received after every onKeyPress event is received for the typed key

Snack, code example, screenshot, or link to a repository

https://github.com/jbrowning/RN071TextInputBackspace

Start with the linked RN071TextInputBackspace reproduction and inspect the TextInput onKeyPress event path on iOS, comparing multiline behavior on iOS 15 and 16. Done means typing and resetting the value no longer produces spurious Backspace events while genuine key events remain.