diff options
| -rw-r--r-- | clippy_lints/src/lines_filter_map_ok.rs | 60 | ||||
| -rw-r--r-- | tests/ui/lines_filter_map_ok.fixed | 6 | ||||
| -rw-r--r-- | tests/ui/lines_filter_map_ok.rs | 6 | ||||
| -rw-r--r-- | tests/ui/lines_filter_map_ok.stderr | 34 |
4 files changed, 74 insertions, 32 deletions
diff --git a/clippy_lints/src/lines_filter_map_ok.rs b/clippy_lints/src/lines_filter_map_ok.rs index 0a5f5a80cb7..00ca553445f 100644 --- a/clippy_lints/src/lines_filter_map_ok.rs +++ b/clippy_lints/src/lines_filter_map_ok.rs @@ -53,18 +53,45 @@ declare_clippy_lint! { #[clippy::version = "1.70.0"] pub LINES_FILTER_MAP_OK, suspicious, - "filtering `std::io::Lines` with `filter_map()` or `flat_map()` might cause an infinite loop" + "filtering `std::io::Lines` with `filter_map()`, `flat_map()`, or `flatten()` might cause an infinite loop" } declare_lint_pass!(LinesFilterMapOk => [LINES_FILTER_MAP_OK]); impl LateLintPass<'_> for LinesFilterMapOk { fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) { - if let ExprKind::MethodCall(fm_method, fm_receiver, [fm_arg], fm_span) = expr.kind + if let ExprKind::MethodCall(fm_method, fm_receiver, fm_args, fm_span) = expr.kind && is_trait_method(cx, expr, sym::Iterator) - && (fm_method.ident.as_str() == "filter_map" || fm_method.ident.as_str() == "flat_map") + && let fm_method_str = fm_method.ident.as_str() + && matches!(fm_method_str, "filter_map" | "flat_map" | "flatten") && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty_adjusted(fm_receiver), sym::IoLines) + && should_lint(cx, fm_args, fm_method_str) { - let lint = match &fm_arg.kind { + span_lint_and_then( + cx, + LINES_FILTER_MAP_OK, + fm_span, + &format!("`{fm_method_str}()` will run forever if the iterator repeatedly produces an `Err`",), + |diag| { + diag.span_note( + fm_receiver.span, + "this expression returning a `std::io::Lines` may produce an infinite number of `Err` in case of a read error"); + diag.span_suggestion( + fm_span, + "replace with", + "map_while(Result::ok)", + Applicability::MaybeIncorrect, + ); + }, + ); + } + } +} + +fn should_lint(cx: &LateContext<'_>, args: &[Expr<'_>], method_str: &str) -> bool { + match args { + [] => method_str == "flatten", + [fm_arg] => { + match &fm_arg.kind { // Detect `Result::ok` ExprKind::Path(qpath) => cx .qpath_res(qpath, fm_arg.hir_id) @@ -86,29 +113,8 @@ impl LateLintPass<'_> for LinesFilterMapOk { } }, _ => false, - }; - if lint { - span_lint_and_then( - cx, - LINES_FILTER_MAP_OK, - fm_span, - &format!( - "`{}()` will run forever if the iterator repeatedly produces an `Err`", - fm_method.ident - ), - |diag| { - diag.span_note( - fm_receiver.span, - "this expression returning a `std::io::Lines` may produce an infinite number of `Err` in case of a read error"); - diag.span_suggestion( - fm_span, - "replace with", - "map_while(Result::ok)", - Applicability::MaybeIncorrect, - ); - }, - ); } - } + }, + _ => false, } } diff --git a/tests/ui/lines_filter_map_ok.fixed b/tests/ui/lines_filter_map_ok.fixed index 74ef6f72957..621115cc132 100644 --- a/tests/ui/lines_filter_map_ok.fixed +++ b/tests/ui/lines_filter_map_ok.fixed @@ -10,11 +10,17 @@ fn main() -> io::Result<()> { // Lint let f = std::fs::File::open("/")?; BufReader::new(f).lines().map_while(Result::ok).for_each(|_| ()); + // Lint + let f = std::fs::File::open("/")?; + BufReader::new(f).lines().map_while(Result::ok).for_each(|_| ()); + let s = "foo\nbar\nbaz\n"; // Lint io::stdin().lines().map_while(Result::ok).for_each(|_| ()); // Lint io::stdin().lines().map_while(Result::ok).for_each(|_| ()); + // Lint + io::stdin().lines().map_while(Result::ok).for_each(|_| ()); // Do not lint (not a `Lines` iterator) io::stdin() .lines() diff --git a/tests/ui/lines_filter_map_ok.rs b/tests/ui/lines_filter_map_ok.rs index 345f4dc5f30..a86efbd6686 100644 --- a/tests/ui/lines_filter_map_ok.rs +++ b/tests/ui/lines_filter_map_ok.rs @@ -10,11 +10,17 @@ fn main() -> io::Result<()> { // Lint let f = std::fs::File::open("/")?; BufReader::new(f).lines().flat_map(Result::ok).for_each(|_| ()); + // Lint + let f = std::fs::File::open("/")?; + BufReader::new(f).lines().flatten().for_each(|_| ()); + let s = "foo\nbar\nbaz\n"; // Lint io::stdin().lines().filter_map(Result::ok).for_each(|_| ()); // Lint io::stdin().lines().filter_map(|x| x.ok()).for_each(|_| ()); + // Lint + io::stdin().lines().flatten().for_each(|_| ()); // Do not lint (not a `Lines` iterator) io::stdin() .lines() diff --git a/tests/ui/lines_filter_map_ok.stderr b/tests/ui/lines_filter_map_ok.stderr index fa2ba0a9a46..9833ab16473 100644 --- a/tests/ui/lines_filter_map_ok.stderr +++ b/tests/ui/lines_filter_map_ok.stderr @@ -24,29 +24,53 @@ note: this expression returning a `std::io::Lines` may produce an infinite numbe LL | BufReader::new(f).lines().flat_map(Result::ok).for_each(|_| ()); | ^^^^^^^^^^^^^^^^^^^^^^^^^ +error: `flatten()` will run forever if the iterator repeatedly produces an `Err` + --> $DIR/lines_filter_map_ok.rs:15:31 + | +LL | BufReader::new(f).lines().flatten().for_each(|_| ()); + | ^^^^^^^^^ help: replace with: `map_while(Result::ok)` + | +note: this expression returning a `std::io::Lines` may produce an infinite number of `Err` in case of a read error + --> $DIR/lines_filter_map_ok.rs:15:5 + | +LL | BufReader::new(f).lines().flatten().for_each(|_| ()); + | ^^^^^^^^^^^^^^^^^^^^^^^^^ + error: `filter_map()` will run forever if the iterator repeatedly produces an `Err` - --> $DIR/lines_filter_map_ok.rs:15:25 + --> $DIR/lines_filter_map_ok.rs:19:25 | LL | io::stdin().lines().filter_map(Result::ok).for_each(|_| ()); | ^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `map_while(Result::ok)` | note: this expression returning a `std::io::Lines` may produce an infinite number of `Err` in case of a read error - --> $DIR/lines_filter_map_ok.rs:15:5 + --> $DIR/lines_filter_map_ok.rs:19:5 | LL | io::stdin().lines().filter_map(Result::ok).for_each(|_| ()); | ^^^^^^^^^^^^^^^^^^^ error: `filter_map()` will run forever if the iterator repeatedly produces an `Err` - --> $DIR/lines_filter_map_ok.rs:17:25 + --> $DIR/lines_filter_map_ok.rs:21:25 | LL | io::stdin().lines().filter_map(|x| x.ok()).for_each(|_| ()); | ^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `map_while(Result::ok)` | note: this expression returning a `std::io::Lines` may produce an infinite number of `Err` in case of a read error - --> $DIR/lines_filter_map_ok.rs:17:5 + --> $DIR/lines_filter_map_ok.rs:21:5 | LL | io::stdin().lines().filter_map(|x| x.ok()).for_each(|_| ()); | ^^^^^^^^^^^^^^^^^^^ -error: aborting due to 4 previous errors +error: `flatten()` will run forever if the iterator repeatedly produces an `Err` + --> $DIR/lines_filter_map_ok.rs:23:25 + | +LL | io::stdin().lines().flatten().for_each(|_| ()); + | ^^^^^^^^^ help: replace with: `map_while(Result::ok)` + | +note: this expression returning a `std::io::Lines` may produce an infinite number of `Err` in case of a read error + --> $DIR/lines_filter_map_ok.rs:23:5 + | +LL | io::stdin().lines().flatten().for_each(|_| ()); + | ^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 6 previous errors |