Multibyte Characters in File Path Cause bat to Crash

Oct 13, 2025 by wbrum.org 120 views

Multibyte Characters in File Path Cause bat to Crash

bat is a powerful command-line text viewer that provides a wide range of features and customization options. However, a recent bug has been reported that causes bat to crash when dealing with multibyte characters in file paths. In this article, we will explore the issue, its causes, and the expected behavior.

When bat is run with a file path containing multibyte characters, it crashes with the following error message:

thread 'main' panicked at /usr/src/debug/rust/rustc-1.84.0-src/library/core/src/str/mod.rs:648:21:
byte index 21 is not a char boundary; it is inside '가' (bytes 20..23) of `File: /tmp/A—B가   <EMPTY>`
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
───────┬──────────────────────

This error message indicates that the issue is related to the way bat handles multibyte characters in file paths.

The expected behavior is that bat should handle multibyte characters in file paths correctly, without crashing. Depending on the width of the terminal, either not crashing or not breaking ANSI color codes should occur.

To reproduce the bug, follow these steps:

Run touch /tmp/A—B가, where ‘—’ is a multibyte UTF-8 character and ’가’ is a multibyte double-width CJK character.
Run bat --terminal-width=30 /tmp/A—B가.

The bug was reported with bat version 0.25.0 (v0.25.0-modified) on Linux 6.13.5-arch1-1. The environment variables and system configuration files are listed below:

Software version

bat: 0.25.0 (v0.25.0-modified)

Operating system

Linux: 6.13.5-arch1-1

Command-line

bat --diagnostic

Environment variables

BAT_CACHE_PATH=<not set>
BAT_CONFIG_PATH=<not set>
BAT_OPTS=<not set>
BAT_PAGER=<not set>
BAT_PAGING=<not set>
BAT_STYLE=<not set>
BAT_TABS=<not set>
BAT_THEME=<not set>
COLORTERM=truecolor
LANG=en_US.UTF-8
LC_ALL=<not set>
LESS=' --RAW-CONTROL-CHARS --tilde --incsearch --ignore-case --clear-screen '
MANPAGER='nvim +Man'\!''
NO_COLOR=<not set>
PAGER=less
SHELL=/bin/bash
TERM=alacritty
XDG_CACHE_HOME=/home/vejkse/.cache
XDG_CONFIG_HOME=/home/vejkse/.config

System Config file

Could not read contents of '/etc/bat/config': No such file or directory (os error 2).

Config file

--theme=gruvbox-dark

Custom assets metadata

Could not read contents of '/home/vejkse/.cache/bat/metadata.yaml': No such file or directory (os error 2).

Custom assets

'/home/vejkse/.cache/bat' not found

Compile time information

Profile: release
Target triple: x86_64-unknown-linux-gnu
Family: unix
OS: linux
Architecture: x86_64
Pointer width: 64
Endian: little
CPU features: fxsr,sse,sse2
Host: x86_64-unknown-linux-gnu

Less version

> less --version
less 668 (PCRE2 regular expressions)
Copyright (C) 1984-2024  Mark Nudelman

less comes with NO WARRANTY, to the extent permitted by law.
For information about the terms of redistribution,
see the file named README in the less distribution.
Home page: https://greenwoodsoftware.com/less

In conclusion, the bug in bat causes it to crash when dealing with multibyte characters in file paths. The expected behavior is that bat should handle multibyte characters correctly, without crashing. To reproduce the bug, follow the steps outlined above. The environment variables and system configuration files are listed above. The bug is likely related to the way bat handles multibyte characters in file paths, and further investigation is needed to resolve the issue.
Multibyte Characters in File Path Cause bat to Crash: Q&A

In our previous article, we explored the issue of bat crashing when dealing with multibyte characters in file paths. In this article, we will answer some frequently asked questions (FAQs) related to this issue.

A: Multibyte characters are characters that require more than one byte to represent in a computer's memory. Examples of multibyte characters include Unicode characters, such as emojis, and non-ASCII characters, such as accented letters.

A: The issue is likely related to the way bat handles multibyte characters in file paths. When bat encounters a multibyte character in a file path, it may not handle it correctly, leading to a crash.

A: The symptoms of this issue include bat crashing with an error message indicating that the byte index is not a char boundary. The error message may also include a backtrace, which can help diagnose the issue.

A: To reproduce this issue, follow these steps:

Run touch /tmp/A—B가, where ‘—’ is a multibyte UTF-8 character and ’가’ is a multibyte double-width CJK character.
Run bat --terminal-width=30 /tmp/A—B가.

A: The expected behavior is that bat should handle multibyte characters in file paths correctly, without crashing. Depending on the width of the terminal, either not crashing or not breaking ANSI color codes should occur.

A: The possible causes of this issue include:

bat's handling of multibyte characters in file paths
terminal width and ANSI color codes
system configuration and environment variables

A: To troubleshoot this issue, follow these steps:

Check the bat version and environment variables.
Run bat --diagnostic to generate a diagnostic report.
Check the system configuration and environment variables.
Try reproducing the issue with a different terminal width and ANSI color codes.

A: To fix this issue, you may need to:

Update bat to the latest version.
Adjust the terminal width and ANSI color codes.
Modify the system configuration and environment variables.
Contact the bat developers for further assistance.

In conclusion, the issue of bat crashing when dealing with multibyte characters in file paths is a complex problem that requires careful troubleshooting and analysis. By following the steps outlined in this article, you can reproduce the issue, troubleshoot it, and potentially fix it. If you are still experiencing issues, please contact the bat developers for further assistance.