Optionally allow expect and unwrap in tests

Author: smoelius

clippy_lints/src/lib.rs

@@ -582,8 +582,17 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     });
 
     let avoid_breaking_exported_api = conf.avoid_breaking_exported_api;
+    let allow_expect_in_tests = conf.allow_expect_in_tests;
+    let allow_unwrap_in_tests = conf.allow_unwrap_in_tests;
     store.register_late_pass(move || Box::new(approx_const::ApproxConstant::new(msrv)));
-    store.register_late_pass(move || Box::new(methods::Methods::new(avoid_breaking_exported_api, msrv)));
+    store.register_late_pass(move || {
+        Box::new(methods::Methods::new(
+            avoid_breaking_exported_api,
+            msrv,
+            allow_expect_in_tests,
+            allow_unwrap_in_tests,
+        ))
+    });
     store.register_late_pass(move || Box::new(matches::Matches::new(msrv)));
     store.register_early_pass(move || Box::new(manual_non_exhaustive::ManualNonExhaustiveStruct::new(msrv)));
     store.register_late_pass(move || Box::new(manual_non_exhaustive::ManualNonExhaustiveEnum::new(msrv)));

clippy_lints/src/methods/expect_used.rs

@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::is_in_test_function;
 use clippy_utils::ty::is_type_diagnostic_item;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
@@ -7,7 +8,7 @@ use rustc_span::sym;
 use super::EXPECT_USED;
 
 /// lint use of `expect()` for `Option`s and `Result`s
-pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>) {
+pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, allow_expect_in_tests: bool) {
     let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs();
 
     let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) {
@@ -18,6 +19,10 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
         None
     };
 
+    if allow_expect_in_tests && is_in_test_function(cx.tcx, expr.hir_id) {
+        return;
+    }
+
     if let Some((lint, kind, none_value)) = mess {
         span_lint_and_help(
             cx,

clippy_lints/src/methods/mod.rs

@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::is_in_test_function;
 use clippy_utils::ty::is_type_diagnostic_item;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
@@ -7,7 +8,7 @@ use rustc_span::sym;
 use super::UNWRAP_USED;
 
 /// lint use of `unwrap()` for `Option`s and `Result`s
-pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>) {
+pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, allow_unwrap_in_tests: bool) {
     let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs();
 
     let mess = if is_type_diagnostic_item(cx, obj_ty, sym::Option) {
@@ -18,6 +19,10 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr
         None
     };
 
+    if allow_unwrap_in_tests && is_in_test_function(cx.tcx, expr.hir_id) {
+        return;
+    }
+
     if let Some((lint, kind, none_value)) = mess {
         span_lint_and_help(
             cx,

clippy_lints/src/methods/unwrap_used.rs

@@ -316,6 +316,14 @@ define_Conf! {
     ///
     /// The maximum size of a file included via `include_bytes!()` or `include_str!()`, in bytes
     (max_include_file_size: u64 = 1_000_000),
+    /// Lint: EXPECT_USED.
+    ///
+    /// Whether `expect` should be allowed in test functions
+    (allow_expect_in_tests: bool = false),
+    /// Lint: UNWRAP_USED.
+    ///
+    /// Whether `unwrap` should be allowed in test functions
+    (allow_unwrap_in_tests: bool = false),
 }
 
 /// Search for the configuration file.

clippy_lints/src/utils/conf.rs

@@ -0,0 +1 @@
+allow-expect-in-tests = true

tests/ui-toml/expect_used/clippy.toml

@@ -0,0 +1,29 @@
+// compile-flags: --test
+#![warn(clippy::expect_used)]
+
+fn expect_option() {
+    let opt = Some(0);
+    let _ = opt.expect("");
+}
+
+fn expect_result() {
+    let res: Result<u8, ()> = Ok(0);
+    let _ = res.expect("");
+}
+
+fn main() {
+    expect_option();
+    expect_result();
+}
+
+#[test]
+fn test_expect_option() {
+    let opt = Some(0);
+    let _ = opt.expect("");
+}
+
+#[test]
+fn test_expect_result() {
+    let res: Result<u8, ()> = Ok(0);
+    let _ = res.expect("");
+}

tests/ui-toml/expect_used/expect_used.rs

@@ -0,0 +1,19 @@
+error: used `expect()` on `an Option` value
+  --> $DIR/expect_used.rs:6:13
+   |
+LL |     let _ = opt.expect("");
+   |             ^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::expect-used` implied by `-D warnings`
+   = help: if this value is an `None`, it will panic
+
+error: used `expect()` on `a Result` value
+  --> $DIR/expect_used.rs:11:13
+   |
+LL |     let _ = res.expect("");
+   |             ^^^^^^^^^^^^^^
+   |
+   = help: if this value is an `Err`, it will panic
+
+error: aborting due to 2 previous errors
+

tests/ui-toml/expect_used/expect_used.stderr

@@ -1,4 +1,4 @@
-error: error reading Clippy's configuration file `$DIR/clippy.toml`: unknown field `foobar`, expected one of `avoid-breaking-exported-api`, `msrv`, `blacklisted-names`, `cognitive-complexity-threshold`, `cyclomatic-complexity-threshold`, `doc-valid-idents`, `too-many-arguments-threshold`, `type-complexity-threshold`, `single-char-binding-names-threshold`, `too-large-for-stack`, `enum-variant-name-threshold`, `enum-variant-size-threshold`, `verbose-bit-mask-threshold`, `literal-representation-threshold`, `trivial-copy-size-limit`, `pass-by-value-size-limit`, `too-many-lines-threshold`, `array-size-threshold`, `vec-box-size-threshold`, `max-trait-bounds`, `max-struct-bools`, `max-fn-params-bools`, `warn-on-all-wildcard-imports`, `disallowed-methods`, `disallowed-types`, `unreadable-literal-lint-fractions`, `upper-case-acronyms-aggressive`, `cargo-ignore-publish`, `standard-macro-braces`, `enforced-import-renames`, `allowed-scripts`, `enable-raw-pointer-heuristic-for-send`, `max-suggested-slice-pattern-length`, `await-holding-invalid-types`, `max-include-file-size`, `third-party` at line 5 column 1
+error: error reading Clippy's configuration file `$DIR/clippy.toml`: unknown field `foobar`, expected one of `avoid-breaking-exported-api`, `msrv`, `blacklisted-names`, `cognitive-complexity-threshold`, `cyclomatic-complexity-threshold`, `doc-valid-idents`, `too-many-arguments-threshold`, `type-complexity-threshold`, `single-char-binding-names-threshold`, `too-large-for-stack`, `enum-variant-name-threshold`, `enum-variant-size-threshold`, `verbose-bit-mask-threshold`, `literal-representation-threshold`, `trivial-copy-size-limit`, `pass-by-value-size-limit`, `too-many-lines-threshold`, `array-size-threshold`, `vec-box-size-threshold`, `max-trait-bounds`, `max-struct-bools`, `max-fn-params-bools`, `warn-on-all-wildcard-imports`, `disallowed-methods`, `disallowed-types`, `unreadable-literal-lint-fractions`, `upper-case-acronyms-aggressive`, `cargo-ignore-publish`, `standard-macro-braces`, `enforced-import-renames`, `allowed-scripts`, `enable-raw-pointer-heuristic-for-send`, `max-suggested-slice-pattern-length`, `await-holding-invalid-types`, `max-include-file-size`, `allow-expect-in-tests`, `allow-unwrap-in-tests`, `third-party` at line 5 column 1
 
 error: aborting due to previous error
 

tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr

@@ -0,0 +1 @@
+allow-unwrap-in-tests = true

tests/ui-toml/unwrap_used/clippy.toml

@@ -0,0 +1,74 @@
+// compile-flags: --test
+
+#![allow(unused_mut, clippy::from_iter_instead_of_collect)]
+#![warn(clippy::unwrap_used)]
+#![deny(clippy::get_unwrap)]
+
+use std::collections::BTreeMap;
+use std::collections::HashMap;
+use std::collections::VecDeque;
+use std::iter::FromIterator;
+
+struct GetFalsePositive {
+    arr: [u32; 3],
+}
+
+impl GetFalsePositive {
+    fn get(&self, pos: usize) -> Option<&u32> {
+        self.arr.get(pos)
+    }
+    fn get_mut(&mut self, pos: usize) -> Option<&mut u32> {
+        self.arr.get_mut(pos)
+    }
+}
+
+fn main() {
+    let mut boxed_slice: Box<[u8]> = Box::new([0, 1, 2, 3]);
+    let mut some_slice = &mut [0, 1, 2, 3];
+    let mut some_vec = vec![0, 1, 2, 3];
+    let mut some_vecdeque: VecDeque<_> = some_vec.iter().cloned().collect();
+    let mut some_hashmap: HashMap<u8, char> = HashMap::from_iter(vec![(1, 'a'), (2, 'b')]);
+    let mut some_btreemap: BTreeMap<u8, char> = BTreeMap::from_iter(vec![(1, 'a'), (2, 'b')]);
+    let mut false_positive = GetFalsePositive { arr: [0, 1, 2] };
+
+    {
+        // Test `get().unwrap()`
+        let _ = boxed_slice.get(1).unwrap();
+        let _ = some_slice.get(0).unwrap();
+        let _ = some_vec.get(0).unwrap();
+        let _ = some_vecdeque.get(0).unwrap();
+        let _ = some_hashmap.get(&1).unwrap();
+        let _ = some_btreemap.get(&1).unwrap();
+        #[allow(clippy::unwrap_used)]
+        let _ = false_positive.get(0).unwrap();
+        // Test with deref
+        let _: u8 = *boxed_slice.get(1).unwrap();
+    }
+
+    {
+        // Test `get_mut().unwrap()`
+        *boxed_slice.get_mut(0).unwrap() = 1;
+        *some_slice.get_mut(0).unwrap() = 1;
+        *some_vec.get_mut(0).unwrap() = 1;
+        *some_vecdeque.get_mut(0).unwrap() = 1;
+        // Check false positives
+        #[allow(clippy::unwrap_used)]
+        {
+            *some_hashmap.get_mut(&1).unwrap() = 'b';
+            *some_btreemap.get_mut(&1).unwrap() = 'b';
+            *false_positive.get_mut(0).unwrap() = 1;
+        }
+    }
+
+    {
+        // Test `get().unwrap().foo()` and `get_mut().unwrap().bar()`
+        let _ = some_vec.get(0..1).unwrap().to_vec();
+        let _ = some_vec.get_mut(0..1).unwrap().to_vec();
+    }
+}
+
+#[test]
+fn test() {
+    let boxed_slice: Box<[u8]> = Box::new([0, 1, 2, 3]);
+    let _ = boxed_slice.get(1).unwrap();
+}