use crate::linter::{Diagnostic, LintResult, Severity, Span};
use regex::Regex;
static EMPTY_STRING_COMPARE: std::sync::LazyLock<Regex> =
std::sync::LazyLock::new(|| Regex::new(r#"\[\[?\s*"?\$\w+"?\s*(=|!=)\s*""\s*\]\]?"#).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 EMPTY_STRING_COMPARE.is_match(line) {
let diagnostic = Diagnostic::new(
"SC2256",
Severity::Info,
r#"Prefer -n/-z over comparison with empty string: use [ -z "$var" ] instead of [ "$var" = "" ]"#.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_sc2256_empty_compare() {
assert_eq!(check(r#"[ "$var" = "" ]"#).diagnostics.len(), 1);
}
#[test]
fn test_sc2256_not_empty_compare() {
assert_eq!(check(r#"[ "$var" != "" ]"#).diagnostics.len(), 1);
}
#[test]
fn test_sc2256_use_z_ok() {
assert_eq!(check(r#"[ -z "$var" ]"#).diagnostics.len(), 0);
}
#[test]
fn test_sc2256_use_n_ok() {
assert_eq!(check(r#"[ -n "$var" ]"#).diagnostics.len(), 0);
}
#[test]
fn test_sc2256_comment() {
assert_eq!(check("# comment").diagnostics.len(), 0);
}
#[test]
fn test_sc2256_empty() {
assert_eq!(check("").diagnostics.len(), 0);
}
#[test]
fn test_sc2256_normal() {
assert_eq!(check("echo test").diagnostics.len(), 0);
}
#[test]
fn test_sc2256_double_bracket() {
assert_eq!(check(r#"[[ "$x" = "" ]]"#).diagnostics.len(), 1);
}
#[test]
fn test_sc2256_value_compare() {
assert_eq!(check(r#"[ "$a" = "value" ]"#).diagnostics.len(), 0);
}
#[test]
fn test_sc2256_unquoted() {
assert_eq!(check(r#"[ $var = "" ]"#).diagnostics.len(), 1);
}
}