iOS only: `onChangeText` of `TextInput` is fired with text longer than `maxLength`

Description

We noticed that sometimes the onChangeText event of TextInput was fired with text longer than maxLength. According to the doc, this behaviour seems to be unexpected.

maxLength:
Limits the maximum number of characters that can be entered.

This happens only on iOS relating to autocompletion.

Steps to reproduce

Here is a snack link to reproduce the issue: https://snack.expo.dev/@yupeng_li/textinput

It contains only a TextInput component and maxLength is set to 3. If you type in bef and let the autocomplete suggestion come up, you will see an alert triggered by onChangeText when text is longer the maxLength.

In the screenshot below, the text returned is "Before", and the text displayed in the input is "ore".

React Native Version

0.71.14

Affected Platforms

Runtime - iOS

Output of npx react-native info

info Fetching system and libraries information...
System:
    OS: macOS 14.1.2
    CPU: (10) arm64 Apple M1 Pro
    Memory: 81.80 MB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 18.17.0 - ~/Library/Caches/fnm_multishells/24849_1670237417415/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 9.6.7 - ~/Library/Caches/fnm_multishells/24849_1670237417415/bin/npm
    Watchman: 2023.10.09.00 - /opt/homebrew/bin/watchman
  Managers:
    CocoaPods: Not Found
  SDKs:
    iOS SDK:
      Platforms: DriverKit 23.0, iOS 17.0, macOS 14.0, tvOS 17.0, watchOS 10.0
    Android SDK: Not Found
  IDEs:
    Android Studio: 2022.3 AI-223.8836.35.2231.10671973
    Xcode: 15.0.1/15A507 - /usr/bin/xcodebuild
  Languages:
    Java: 11.0.19 - /Users/yupeng/.sdkman/candidates/java/11.0.19-tem/bin/javac
  npmPackages:
    @react-native-community/cli: Not Found
    react: 18.2.0 => 18.2.0
    react-native: 0.71.14 => 0.71.14
    react-native-macos: Not Found
  npmGlobalPackages:
    *react-native*: Not Found
info React Native v0.73.0 is now available (your project is running on v0.71.14).
info Changelog: https://github.com/facebook/react-native/releases/tag/v0.73.0
info Diff: https://react-native-community.github.io/upgrade-helper/?from=0.71.14
info For more info, check out "https://reactnative.dev/docs/upgrading".

Stacktrace or Logs

No stacktrace

Reproducer

https://snack.expo.dev/@yupeng_li/textinput

Screenshots and Videos

No response

从链接的 Snack reproducer 以及 iOS 上 TextInput onChangeText/maxLength 的行为入手，尤其要关注 autocomplete 插入文本时的情况。跟踪 iOS TextInput 的入口点，以确定为什么字段显示“ore”，而 callback 却接收到“Before”。当 autocomplete 无法使 onChangeText 报告长度超过 maxLength 的文本，并且 reproducer 的行为已修正时，即视为完成。