macOS: Chinese IME keystrokes leak into terminal during composition

[ChrisOr-Dev]

Issue Description

When using a Chinese input method (Cangjie, Zhuyin, or Pinyin) on macOS, the Roman letter keystrokes used to compose Chinese characters leak into the terminal input, causing unintended characters to appear.

For example, typing a Chinese character that requires pressing c twice in Cangjie input results in cc appearing in the terminal prompt in addition to (or instead of) the intended Chinese character.

This is a regression/continuation of the same root cause reported in:

• Discussion macOS: Some input method keybinds penetrates #2628 — macOS: Some input method keybinds penetrates (Japanese AquaSKK, unfixed)
• Issue Ctrl+key keybinds broken during Chinese IME composition (macOS) #11550 — Ctrl+key keybinds broken during Chinese IME composition (closed by bot, unfixed)

The issue has persisted unfixed through at least v1.3.1.

Expected Behavior

IME keystrokes should be consumed entirely by the input method and not forwarded to the terminal. This is the standard macOS NSResponder behavior. Both iTerm2 and Terminal.app handle this correctly — only the composed Chinese character is sent to the terminal.

Actual Behavior

The Roman letter keystrokes used during Chinese IME composition (e.g. c, c for a Cangjie character) are leaked into the terminal, producing unintended literal characters in the shell prompt alongside or instead of the composed Chinese character.

Reproduction Steps

1. Open Ghostty on macOS.
2. Switch to a Chinese input method (Cangjie, Zhuyin, or Pinyin).
3. Type any Chinese character that requires multiple Roman keystrokes (e.g. press c twice in Cangjie).
4. Observe that the Roman keystrokes (e.g. cc) appear literally in the terminal prompt.
5. Open Terminal.app or iTerm2 and repeat — the leak does not occur.

Ghostty Logs

No relevant logs captured; the issue is reproducible consistently.

Ghostty Version

Ghostty 1.3.1

Version
  - version: 1.3.1
  - channel: stable
Build Config
  - Zig version   : 0.15.2
  - build mode    : .ReleaseFast
  - app runtime   : .none
  - font engine   : .coretext
  - renderer      : renderer.generic.Renderer(renderer.Metal)
  - libxev        : kqueue

OS Version Information

macOS 26.4.1 (Build 25E253)

Minimal Ghostty Configuration

# Default configuration — reproducible with no custom config

I acknowledge that:

• I have reviewed the FAQ and confirm that my issue is NOT among them.
• I have searched the Ghostty repository (both open and closed Discussions and Issues) and confirm this is not a duplicate of an existing issue or discussion.
• I have checked the Preview tab on all text fields to ensure that everything looks right, and have wrapped all configuration and code in code blocks.