diff --git a/CHANGELOG.md b/CHANGELOG.md index 64f9379b3..285a2ff80 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1755,6 +1755,7 @@ Released 2018-09-13 [`out_of_bounds_indexing`]: https://rust-lang.github.io/rust-clippy/master/index.html#out_of_bounds_indexing [`overflow_check_conditional`]: https://rust-lang.github.io/rust-clippy/master/index.html#overflow_check_conditional [`panic`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic +[`panic_in_result_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_in_result_fn [`panic_params`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_params [`panicking_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#panicking_unwrap [`partialeq_ne_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#partialeq_ne_impl diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 2020ef785..1795fd10f 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -269,6 +269,7 @@ mod open_options; mod option_env_unwrap; mod option_if_let_else; mod overflow_check_conditional; +mod panic_in_result_fn; mod panic_unimplemented; mod partialeq_ne_impl; mod path_buf_push_overwrite; @@ -751,6 +752,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &option_env_unwrap::OPTION_ENV_UNWRAP, &option_if_let_else::OPTION_IF_LET_ELSE, &overflow_check_conditional::OVERFLOW_CHECK_CONDITIONAL, + &panic_in_result_fn::PANIC_IN_RESULT_FN, &panic_unimplemented::PANIC, &panic_unimplemented::PANIC_PARAMS, &panic_unimplemented::TODO, @@ -1091,6 +1093,8 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: store.register_late_pass(|| box manual_async_fn::ManualAsyncFn); store.register_early_pass(|| box redundant_field_names::RedundantFieldNames); store.register_late_pass(|| box vec_resize_to_zero::VecResizeToZero); + store.register_late_pass(|| box panic_in_result_fn::PanicInResultFn); + let single_char_binding_names_threshold = conf.single_char_binding_names_threshold; store.register_early_pass(move || box non_expressive_names::NonExpressiveNames { single_char_binding_names_threshold, @@ -1135,6 +1139,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&missing_doc::MISSING_DOCS_IN_PRIVATE_ITEMS), LintId::of(&missing_inline::MISSING_INLINE_IN_PUBLIC_ITEMS), LintId::of(&modulo_arithmetic::MODULO_ARITHMETIC), + LintId::of(&panic_in_result_fn::PANIC_IN_RESULT_FN), LintId::of(&panic_unimplemented::PANIC), LintId::of(&panic_unimplemented::TODO), LintId::of(&panic_unimplemented::UNIMPLEMENTED), diff --git a/clippy_lints/src/panic_in_result_fn.rs b/clippy_lints/src/panic_in_result_fn.rs new file mode 100644 index 000000000..4077aba6e --- /dev/null +++ b/clippy_lints/src/panic_in_result_fn.rs @@ -0,0 +1,90 @@ +use crate::utils::{is_expn_of, is_type_diagnostic_item, return_ty, span_lint_and_then}; +use rustc_hir as hir; +use rustc_hir::intravisit::{self, FnKind, NestedVisitorMap, Visitor}; +use rustc_hir::Expr; +use rustc_lint::{LateContext, LateLintPass}; +use rustc_middle::hir::map::Map; +use rustc_session::{declare_lint_pass, declare_tool_lint}; +use rustc_span::Span; + +declare_clippy_lint! { + /// **What it does:** Checks for usage of `panic!`, `unimplemented!`, `todo!` or `unreachable!` in a function of type result. + /// + /// **Why is this bad?** For some codebases, it is desirable for functions of type result to return an error instead of crashing. Hence unimplemented, panic and unreachable should be avoided. + /// + /// **Known problems:** None. + /// + /// **Example:** + /// + /// ```rust + /// fn result_with_panic() -> Result + /// { + /// panic!("error"); + /// } + /// ``` + pub PANIC_IN_RESULT_FN, + restriction, + "functions of type `Result<..>` that contain `panic!()`, `todo!()` or `unreachable()` or `unimplemented()` " +} + +declare_lint_pass!(PanicInResultFn => [PANIC_IN_RESULT_FN]); + +impl<'tcx> LateLintPass<'tcx> for PanicInResultFn { + fn check_fn( + &mut self, + cx: &LateContext<'tcx>, + fn_kind: FnKind<'tcx>, + _: &'tcx hir::FnDecl<'tcx>, + body: &'tcx hir::Body<'tcx>, + span: Span, + hir_id: hir::HirId, + ) { + if !matches!(fn_kind, FnKind::Closure(_)) + && is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym!(result_type)) + { + lint_impl_body(cx, span, body); + } + } +} + +struct FindPanicUnimplementedUnreachable { + result: Vec, +} + +impl<'tcx> Visitor<'tcx> for FindPanicUnimplementedUnreachable { + type Map = Map<'tcx>; + + fn visit_expr(&mut self, expr: &'tcx Expr<'_>) { + if ["unimplemented", "unreachable", "panic", "todo"] + .iter() + .any(|fun| is_expn_of(expr.span, fun).is_some()) + { + self.result.push(expr.span); + } + // and check sub-expressions + intravisit::walk_expr(self, expr); + } + + fn nested_visit_map(&mut self) -> NestedVisitorMap { + NestedVisitorMap::None + } +} + +fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, body: &'tcx hir::Body<'tcx>) { + let mut panics = FindPanicUnimplementedUnreachable { result: Vec::new() }; + panics.visit_expr(&body.value); + if !panics.result.is_empty() { + span_lint_and_then( + cx, + PANIC_IN_RESULT_FN, + impl_span, + "used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`", + move |diag| { + diag.help( + "`unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing", + ); + diag.span_note(panics.result, "return Err() instead of panicking"); + }, + ); + } +} diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs index 6697835e9..04d486438 100644 --- a/src/lintlist/mod.rs +++ b/src/lintlist/mod.rs @@ -1718,6 +1718,13 @@ pub static ref ALL_LINTS: Vec = vec![ deprecation: None, module: "panic_unimplemented", }, + Lint { + name: "panic_in_result_fn", + group: "restriction", + desc: "functions of type `Result<..>` that contain `panic!()`, `todo!()` or `unreachable()` or `unimplemented()` ", + deprecation: None, + module: "panic_in_result_fn", + }, Lint { name: "panic_params", group: "style", diff --git a/tests/ui/panic_in_result_fn.rs b/tests/ui/panic_in_result_fn.rs new file mode 100644 index 000000000..287726f7a --- /dev/null +++ b/tests/ui/panic_in_result_fn.rs @@ -0,0 +1,70 @@ +#![warn(clippy::panic_in_result_fn)] + +struct A; + +impl A { + fn result_with_panic() -> Result // should emit lint + { + panic!("error"); + } + + fn result_with_unimplemented() -> Result // should emit lint + { + unimplemented!(); + } + + fn result_with_unreachable() -> Result // should emit lint + { + unreachable!(); + } + + fn result_with_todo() -> Result // should emit lint + { + todo!("Finish this"); + } + + fn other_with_panic() // should not emit lint + { + panic!(""); + } + + fn other_with_unreachable() // should not emit lint + { + unreachable!(); + } + + fn other_with_unimplemented() // should not emit lint + { + unimplemented!(); + } + + fn other_with_todo() // should not emit lint + { + todo!("finish this") + } + + fn result_without_banned_functions() -> Result // should not emit lint + { + Ok(true) + } +} + +fn function_result_with_panic() -> Result // should emit lint +{ + panic!("error"); +} + +fn todo() { + println!("something"); +} + +fn function_result_with_custom_todo() -> Result // should not emit lint +{ + todo(); + Ok(true) +} + +fn main() -> Result<(), String> { + todo!("finish main method"); + Ok(()) +} diff --git a/tests/ui/panic_in_result_fn.stderr b/tests/ui/panic_in_result_fn.stderr new file mode 100644 index 000000000..c6936fd86 --- /dev/null +++ b/tests/ui/panic_in_result_fn.stderr @@ -0,0 +1,105 @@ +error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result` + --> $DIR/panic_in_result_fn.rs:6:5 + | +LL | / fn result_with_panic() -> Result // should emit lint +LL | | { +LL | | panic!("error"); +LL | | } + | |_____^ + | + = note: `-D clippy::panic-in-result-fn` implied by `-D warnings` + = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing +note: return Err() instead of panicking + --> $DIR/panic_in_result_fn.rs:8:9 + | +LL | panic!("error"); + | ^^^^^^^^^^^^^^^^ + = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info) + +error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result` + --> $DIR/panic_in_result_fn.rs:11:5 + | +LL | / fn result_with_unimplemented() -> Result // should emit lint +LL | | { +LL | | unimplemented!(); +LL | | } + | |_____^ + | + = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing +note: return Err() instead of panicking + --> $DIR/panic_in_result_fn.rs:13:9 + | +LL | unimplemented!(); + | ^^^^^^^^^^^^^^^^^ + = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info) + +error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result` + --> $DIR/panic_in_result_fn.rs:16:5 + | +LL | / fn result_with_unreachable() -> Result // should emit lint +LL | | { +LL | | unreachable!(); +LL | | } + | |_____^ + | + = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing +note: return Err() instead of panicking + --> $DIR/panic_in_result_fn.rs:18:9 + | +LL | unreachable!(); + | ^^^^^^^^^^^^^^^ + = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info) + +error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result` + --> $DIR/panic_in_result_fn.rs:21:5 + | +LL | / fn result_with_todo() -> Result // should emit lint +LL | | { +LL | | todo!("Finish this"); +LL | | } + | |_____^ + | + = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing +note: return Err() instead of panicking + --> $DIR/panic_in_result_fn.rs:23:9 + | +LL | todo!("Finish this"); + | ^^^^^^^^^^^^^^^^^^^^^ + = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info) + +error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result` + --> $DIR/panic_in_result_fn.rs:52:1 + | +LL | / fn function_result_with_panic() -> Result // should emit lint +LL | | { +LL | | panic!("error"); +LL | | } + | |_^ + | + = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing +note: return Err() instead of panicking + --> $DIR/panic_in_result_fn.rs:54:5 + | +LL | panic!("error"); + | ^^^^^^^^^^^^^^^^ + = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info) + +error: used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result` + --> $DIR/panic_in_result_fn.rs:67:1 + | +LL | / fn main() -> Result<(), String> { +LL | | todo!("finish main method"); +LL | | Ok(()) +LL | | } + | |_^ + | + = help: `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing +note: return Err() instead of panicking + --> $DIR/panic_in_result_fn.rs:68:5 + | +LL | todo!("finish main method"); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info) + +error: aborting due to 6 previous errors +