enforce LC_ALL=C for ls, fix #1715

[yangjuncode]

enforce LC_ALL=C for ls, fix #1715

RTK ls Locale Bug — Root Cause Analysis

Symptom

• ls shows normal directory output
• rtk ls returns (empty) even when the directory contains files

Root Cause

RTK's ls parser relies on a date regex that only matches English month names (@src/cmds/system/ls.rs:15-18):

static ref LS_DATE_RE: Regex = Regex::new(
    r"\s+(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s+\d{1,2}\s+(?:\d{4}|\d{2}:\d{2})\s+"
).unwrap();

This regex is used in parse_ls_line() (@ls.rs:124) to anchor the line and extract the filename:

fn parse_ls_line(line: &str) -> Option<(char, u64, String)> {
    let date_match = LS_DATE_RE.find(line)?;  // Returns None for non-English months
    let name = line[date_match.end()..].to_string();
    // ...
}

When the system locale is non-English (e.g., Chinese zh_CN.UTF-8), ls -la outputs localized month names:

# English locale (C)
-rw-r--r-- 1 user staff 1234 May  5 12:00 file.txt

# Chinese locale (zh_CN.UTF-8)
-rw-r--r-- 1 user staff 1234  5月  5 12:00 file.txt

The regex fails to match 5月 (or any non-English month), so parse_ls_line() returns None for every line. All lines are skipped by continue in compact_ls() (@ls.rs:166). With zero directories and zero files parsed, the function falls into the empty case (@ls.rs:193-195):

if dirs.is_empty() && files.is_empty() {
    return ("(empty)\n".to_string(), String::new());
}

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