REPL History Ghosting: Spurious characters (e.g., 'c') appear when cycling through history via Arrow keys

[JadeYao-z]

Description

The REPL line editor fails to properly clear the prompt or calculate cursor position when navigating history with Arrow Keys. This results in "ghost" characters (commonly the letter c) being appended or prepended to the input line. This issue is reproducible across glibc (Fedora, NixOS) and musl (Alpine) environments.

Environment

• Engine: quickjs-ng (version 0.11.0).
• Distros: Fedora, NixOS, Alpine (both apk and source build).

Steps to Reproduce

1. Enter several lines of complex code into the REPL

let b = "    hello  :  1"
b
console.log(`索引 ${index}: '${char}'`);
[...b].forEach((v, i) => {console.log(`${v} ${i}`)})
console.log(`索引 ${index}: '${char}'`);
console.log(1)
console.log(2)

2. Press the Up Arrow key several times to cycle through the history.
3. Observe the input line.

Observed Behavior

As you scroll, characters like c (likely remnants of ANSI escape sequences like \x1b[C) begin to leak into the prompt. The line becomes visually corrupted, and the ghost characters do not represent actual code input.

[chqrlie]

This may be caused by your usage of Chinese ideograms is the code typed at the console prompt.
I shall double check but I am not sure I handled double width characters correctly.
Can you confirm that the issue only occurs when you iterate through lines that display such characters?