use crate::linter::{Diagnostic, LintResult, Severity, Span};
use regex::Regex;
static LET_COMMAND: std::sync::LazyLock<Regex> = std::sync::LazyLock::new(|| {
Regex::new(r"\blet\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 line.trim_start().starts_with("echo ") {
continue;
}
if LET_COMMAND.is_match(line) {
let diagnostic = Diagnostic::new(
"SC2219",
Severity::Info,
"Prefer (( expr )) to 'let expr' for arithmetic - more readable and consistent"
.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_sc2219_let_increment() {
let code = r#"let count=count+1"#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 1);
}
#[test]
fn test_sc2219_double_paren_ok() {
let code = r#"(( count = count + 1 ))"#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 0);
}
#[test]
fn test_sc2219_let_assignment() {
let code = r#"let x=5"#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 1);
}
#[test]
fn test_sc2219_let_subtraction() {
let code = r#"let y=y-2"#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 1);
}
#[test]
fn test_sc2219_let_multiply() {
let code = r#"let z=z*3"#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 1);
}
#[test]
fn test_sc2219_let_divide() {
let code = r#"let a=a/2"#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 1);
}
#[test]
fn test_sc2219_comment_skipped() {
let code = r#"# let x=x+1"#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 0);
}
#[test]
fn test_sc2219_string_literal() {
let code = r#"echo "let x=y+1""#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 0); }
#[test]
fn test_sc2219_let_compound() {
let code = r#"let "x = y + z""#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 1);
}
#[test]
fn test_sc2219_arithmetic_ok() {
let code = r#"x=$((x + 1))"#;
let result = check(code);
assert_eq!(result.diagnostics.len(), 0);
}
}