use crate::linter::{Diagnostic, LintResult, Severity, Span};
use regex::Regex;
static USELESS_CAT: std::sync::LazyLock<Regex> =
std::sync::LazyLock::new(|| Regex::new(r"\bcat\s+[^\s|-][^\s|]*\s*\|").unwrap());
pub fn check(source: &str) -> LintResult {
let mut result = LintResult::new();
for (line_num, line) in source.lines().enumerate() {
let line_num = line_num + 1;
if line.trim_start().starts_with('#') {
continue;
}
if USELESS_CAT.is_match(line) {
let diagnostic = Diagnostic::new(
"SC2298",
Severity::Info,
"Use < file instead of cat file | for better performance".to_string(),
Span::new(line_num, 1, line_num, line.len() + 1),
);
result.add(diagnostic);
}
}
result
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_sc2298_cat_pipe() {
let code = "cat file | grep pattern";
assert_eq!(check(code).diagnostics.len(), 1);
}
#[test]
fn test_sc2298_redirect_ok() {
let code = "grep pattern < file";
assert_eq!(check(code).diagnostics.len(), 0);
}
#[test]
fn test_sc2298_cat_multiple_ok() {
let code = "cat file1 file2 | grep";
assert_eq!(check(code).diagnostics.len(), 0);
}
#[test]
fn test_sc2298_comment() {
let code = "# cat file | grep";
assert_eq!(check(code).diagnostics.len(), 0);
}
#[test]
fn test_sc2298_empty() {
assert_eq!(check("").diagnostics.len(), 0);
}
#[test]
fn test_sc2298_normal() {
assert_eq!(check("echo test").diagnostics.len(), 0);
}
#[test]
fn test_sc2298_cat_no_pipe_ok() {
let code = "cat file";
assert_eq!(check(code).diagnostics.len(), 0);
}
#[test]
fn test_sc2298_pipe_without_cat_ok() {
let code = "echo test | grep t";
assert_eq!(check(code).diagnostics.len(), 0);
}
#[test]
fn test_sc2298_cat_dash_ok() {
let code = "cat - | grep pattern";
assert_eq!(check(code).diagnostics.len(), 0);
}
#[test]
fn test_sc2298_with_path() {
let code = "cat /path/to/file | sort";
assert_eq!(check(code).diagnostics.len(), 1);
}
}