| use std::fmt::Display; |
| |
| use clippy_utils::consts::{constant, Constant}; |
| use clippy_utils::diagnostics::{span_lint, span_lint_and_help}; |
| use clippy_utils::source::snippet_opt; |
| use clippy_utils::{match_def_path, paths}; |
| use if_chain::if_chain; |
| use rustc_ast::ast::{LitKind, StrStyle}; |
| use rustc_hir::{BorrowKind, Expr, ExprKind}; |
| use rustc_lint::{LateContext, LateLintPass}; |
| use rustc_session::{declare_lint_pass, declare_tool_lint}; |
| use rustc_span::source_map::{BytePos, Span}; |
| |
| declare_clippy_lint! { |
| /// ### What it does |
| /// Checks [regex](https://crates.io/crates/regex) creation |
| /// (with `Regex::new`, `RegexBuilder::new`, or `RegexSet::new`) for correct |
| /// regex syntax. |
| /// |
| /// ### Why is this bad? |
| /// This will lead to a runtime panic. |
| /// |
| /// ### Example |
| /// ```ignore |
| /// Regex::new("(") |
| /// ``` |
| #[clippy::version = "pre 1.29.0"] |
| pub INVALID_REGEX, |
| correctness, |
| "invalid regular expressions" |
| } |
| |
| declare_clippy_lint! { |
| /// ### What it does |
| /// Checks for trivial [regex](https://crates.io/crates/regex) |
| /// creation (with `Regex::new`, `RegexBuilder::new`, or `RegexSet::new`). |
| /// |
| /// ### Why is this bad? |
| /// Matching the regex can likely be replaced by `==` or |
| /// `str::starts_with`, `str::ends_with` or `std::contains` or other `str` |
| /// methods. |
| /// |
| /// ### Known problems |
| /// If the same regex is going to be applied to multiple |
| /// inputs, the precomputations done by `Regex` construction can give |
| /// significantly better performance than any of the `str`-based methods. |
| /// |
| /// ### Example |
| /// ```ignore |
| /// Regex::new("^foobar") |
| /// ``` |
| #[clippy::version = "pre 1.29.0"] |
| pub TRIVIAL_REGEX, |
| nursery, |
| "trivial regular expressions" |
| } |
| |
| declare_lint_pass!(Regex => [INVALID_REGEX, TRIVIAL_REGEX]); |
| |
| impl<'tcx> LateLintPass<'tcx> for Regex { |
| fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { |
| if_chain! { |
| if let ExprKind::Call(fun, [arg]) = expr.kind; |
| if let ExprKind::Path(ref qpath) = fun.kind; |
| if let Some(def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id(); |
| then { |
| if match_def_path(cx, def_id, &paths::REGEX_NEW) || |
| match_def_path(cx, def_id, &paths::REGEX_BUILDER_NEW) { |
| check_regex(cx, arg, true); |
| } else if match_def_path(cx, def_id, &paths::REGEX_BYTES_NEW) || |
| match_def_path(cx, def_id, &paths::REGEX_BYTES_BUILDER_NEW) { |
| check_regex(cx, arg, false); |
| } else if match_def_path(cx, def_id, &paths::REGEX_SET_NEW) { |
| check_set(cx, arg, true); |
| } else if match_def_path(cx, def_id, &paths::REGEX_BYTES_SET_NEW) { |
| check_set(cx, arg, false); |
| } |
| } |
| } |
| } |
| } |
| |
| fn lint_syntax_error(cx: &LateContext<'_>, error: ®ex_syntax::Error, unescaped: &str, base: Span, offset: u8) { |
| let parts: Option<(_, _, &dyn Display)> = match &error { |
| regex_syntax::Error::Parse(e) => Some((e.span(), e.auxiliary_span(), e.kind())), |
| regex_syntax::Error::Translate(e) => Some((e.span(), None, e.kind())), |
| _ => None, |
| }; |
| |
| let convert_span = |regex_span: ®ex_syntax::ast::Span| { |
| let offset = u32::from(offset); |
| let start = base.lo() + BytePos(u32::try_from(regex_span.start.offset).expect("offset too large") + offset); |
| let end = base.lo() + BytePos(u32::try_from(regex_span.end.offset).expect("offset too large") + offset); |
| |
| Span::new(start, end, base.ctxt(), base.parent()) |
| }; |
| |
| if let Some((primary, auxiliary, kind)) = parts |
| && let Some(literal_snippet) = snippet_opt(cx, base) |
| && let Some(inner) = literal_snippet.get(offset as usize..) |
| // Only convert to native rustc spans if the parsed regex matches the |
| // source snippet exactly, to ensure the span offsets are correct |
| && inner.get(..unescaped.len()) == Some(unescaped) |
| { |
| let spans = if let Some(auxiliary) = auxiliary { |
| vec![convert_span(primary), convert_span(auxiliary)] |
| } else { |
| vec![convert_span(primary)] |
| }; |
| |
| span_lint(cx, INVALID_REGEX, spans, &format!("regex syntax error: {kind}")); |
| } else { |
| span_lint_and_help( |
| cx, |
| INVALID_REGEX, |
| base, |
| &error.to_string(), |
| None, |
| "consider using a raw string literal: `r\"..\"`", |
| ); |
| } |
| } |
| |
| fn const_str<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> Option<String> { |
| constant(cx, cx.typeck_results(), e).and_then(|(c, _)| match c { |
| Constant::Str(s) => Some(s), |
| _ => None, |
| }) |
| } |
| |
| fn is_trivial_regex(s: ®ex_syntax::hir::Hir) -> Option<&'static str> { |
| use regex_syntax::hir::Anchor::{EndText, StartText}; |
| use regex_syntax::hir::HirKind::{Alternation, Anchor, Concat, Empty, Literal}; |
| |
| let is_literal = |e: &[regex_syntax::hir::Hir]| e.iter().all(|e| matches!(*e.kind(), Literal(_))); |
| |
| match *s.kind() { |
| Empty | Anchor(_) => Some("the regex is unlikely to be useful as it is"), |
| Literal(_) => Some("consider using `str::contains`"), |
| Alternation(ref exprs) => { |
| if exprs.iter().all(|e| e.kind().is_empty()) { |
| Some("the regex is unlikely to be useful as it is") |
| } else { |
| None |
| } |
| }, |
| Concat(ref exprs) => match (exprs[0].kind(), exprs[exprs.len() - 1].kind()) { |
| (&Anchor(StartText), &Anchor(EndText)) if exprs[1..(exprs.len() - 1)].is_empty() => { |
| Some("consider using `str::is_empty`") |
| }, |
| (&Anchor(StartText), &Anchor(EndText)) if is_literal(&exprs[1..(exprs.len() - 1)]) => { |
| Some("consider using `==` on `str`s") |
| }, |
| (&Anchor(StartText), &Literal(_)) if is_literal(&exprs[1..]) => Some("consider using `str::starts_with`"), |
| (&Literal(_), &Anchor(EndText)) if is_literal(&exprs[1..(exprs.len() - 1)]) => { |
| Some("consider using `str::ends_with`") |
| }, |
| _ if is_literal(exprs) => Some("consider using `str::contains`"), |
| _ => None, |
| }, |
| _ => None, |
| } |
| } |
| |
| fn check_set<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, utf8: bool) { |
| if_chain! { |
| if let ExprKind::AddrOf(BorrowKind::Ref, _, expr) = expr.kind; |
| if let ExprKind::Array(exprs) = expr.kind; |
| then { |
| for expr in exprs { |
| check_regex(cx, expr, utf8); |
| } |
| } |
| } |
| } |
| |
| fn check_regex<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, utf8: bool) { |
| let mut parser = regex_syntax::ParserBuilder::new() |
| .unicode(true) |
| .allow_invalid_utf8(!utf8) |
| .build(); |
| |
| if let ExprKind::Lit(ref lit) = expr.kind { |
| if let LitKind::Str(ref r, style) = lit.node { |
| let r = r.as_str(); |
| let offset = if let StrStyle::Raw(n) = style { 2 + n } else { 1 }; |
| match parser.parse(r) { |
| Ok(r) => { |
| if let Some(repl) = is_trivial_regex(&r) { |
| span_lint_and_help(cx, TRIVIAL_REGEX, expr.span, "trivial regex", None, repl); |
| } |
| }, |
| Err(e) => lint_syntax_error(cx, &e, r, expr.span, offset), |
| } |
| } |
| } else if let Some(r) = const_str(cx, expr) { |
| match parser.parse(&r) { |
| Ok(r) => { |
| if let Some(repl) = is_trivial_regex(&r) { |
| span_lint_and_help(cx, TRIVIAL_REGEX, expr.span, "trivial regex", None, repl); |
| } |
| }, |
| Err(e) => span_lint(cx, INVALID_REGEX, expr.span, &e.to_string()), |
| } |
| } |
| } |