Auto merge of rust-lang#8897 - tamaroning:improve_dbg, r=Alexendoo

Introduce `allow-dbg-in-tests` config value

related to: Issue rust-lang#8758,  PR rust-lang/rust-clippy#8838

changelog: Introduced `allow-dbg-in-tests` config value. [dbg_macro] does not allow `dbg!` in test code by default.

clippy_lints/src/dbg_macro.rs

@@ -5,7 +5,7 @@ use clippy_utils::{is_in_cfg_test, is_in_test_function};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::sym;
 
 declare_clippy_lint! {
@@ -30,14 +30,27 @@ declare_clippy_lint! {
     "`dbg!` macro is intended as a debugging tool"
 }
 
-declare_lint_pass!(DbgMacro => [DBG_MACRO]);
+#[derive(Copy, Clone)]
+pub struct DbgMacro {
+    allow_dbg_in_tests: bool,
+}
+
+impl_lint_pass!(DbgMacro => [DBG_MACRO]);
+
+impl DbgMacro {
+    pub fn new(allow_dbg_in_tests: bool) -> Self {
+        DbgMacro { allow_dbg_in_tests }
+    }
+}
 
 impl LateLintPass<'_> for DbgMacro {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
         let Some(macro_call) = root_macro_call_first_node(cx, expr) else { return };
         if cx.tcx.is_diagnostic_item(sym::dbg_macro, macro_call.def_id) {
-            // we make an exception for test code
-            if is_in_test_function(cx.tcx, expr.hir_id) || is_in_cfg_test(cx.tcx, expr.hir_id) {
+            // allows `dbg!` in test code if allow-dbg-in-test is set to true in clippy.toml
+            if self.allow_dbg_in_tests
+                && (is_in_test_function(cx.tcx, expr.hir_id) || is_in_cfg_test(cx.tcx, expr.hir_id))
+            {
                 return;
             }
             let mut applicability = Applicability::MachineApplicable;

clippy_lints/src/lib.rs

@@ -888,7 +888,8 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|| Box::new(default_union_representation::DefaultUnionRepresentation));
     store.register_late_pass(|| Box::new(only_used_in_recursion::OnlyUsedInRecursion));
     store.register_late_pass(|| Box::new(significant_drop_in_scrutinee::SignificantDropInScrutinee));
-    store.register_late_pass(|| Box::new(dbg_macro::DbgMacro));
+    let allow_dbg_in_tests = conf.allow_dbg_in_tests;
+    store.register_late_pass(move || Box::new(dbg_macro::DbgMacro::new(allow_dbg_in_tests)));
     let cargo_ignore_publish = conf.cargo_ignore_publish;
     store.register_late_pass(move || {
         Box::new(cargo::Cargo {

clippy_lints/src/utils/conf.rs

@@ -340,6 +340,10 @@ define_Conf! {
     ///
     /// Whether `unwrap` should be allowed in test functions
     (allow_unwrap_in_tests: bool = false),
+    /// Lint: DBG_MACRO.
+    ///
+    /// Whether `dbg!` should be allowed in test functions
+    (allow_dbg_in_tests: bool = false),
 }
 
 /// Search for the configuration file.

tests/ui-toml/dbg_macro/clippy.toml

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

tests/ui-toml/dbg_macro/dbg_macro.rs

@@ -0,0 +1,39 @@
+// compile-flags: --test
+#![warn(clippy::dbg_macro)]
+
+fn foo(n: u32) -> u32 {
+    if let Some(n) = dbg!(n.checked_sub(4)) { n } else { n }
+}
+
+fn factorial(n: u32) -> u32 {
+    if dbg!(n <= 1) {
+        dbg!(1)
+    } else {
+        dbg!(n * factorial(n - 1))
+    }
+}
+
+fn main() {
+    dbg!(42);
+    dbg!(dbg!(dbg!(42)));
+    foo(3) + dbg!(factorial(4));
+    dbg!(1, 2, dbg!(3, 4));
+    dbg!(1, 2, 3, 4, 5);
+}
+
+#[test]
+pub fn issue8481() {
+    dbg!(1);
+}
+
+#[cfg(test)]
+fn foo2() {
+    dbg!(1);
+}
+
+#[cfg(test)]
+mod mod1 {
+    fn func() {
+        dbg!(1);
+    }
+}

tests/ui-toml/dbg_macro/dbg_macro.stderr

@@ -0,0 +1,102 @@
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:5:22
+   |
+LL |     if let Some(n) = dbg!(n.checked_sub(4)) { n } else { n }
+   |                      ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::dbg-macro` implied by `-D warnings`
+help: ensure to avoid having uses of it in version control
+   |
+LL |     if let Some(n) = n.checked_sub(4) { n } else { n }
+   |                      ~~~~~~~~~~~~~~~~
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:9:8
+   |
+LL |     if dbg!(n <= 1) {
+   |        ^^^^^^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |     if n <= 1 {
+   |        ~~~~~~
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:10:9
+   |
+LL |         dbg!(1)
+   |         ^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |         1
+   |
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:12:9
+   |
+LL |         dbg!(n * factorial(n - 1))
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |         n * factorial(n - 1)
+   |
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:17:5
+   |
+LL |     dbg!(42);
+   |     ^^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |     42;
+   |     ~~
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:18:5
+   |
+LL |     dbg!(dbg!(dbg!(42)));
+   |     ^^^^^^^^^^^^^^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |     dbg!(dbg!(42));
+   |     ~~~~~~~~~~~~~~
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:19:14
+   |
+LL |     foo(3) + dbg!(factorial(4));
+   |              ^^^^^^^^^^^^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |     foo(3) + factorial(4);
+   |              ~~~~~~~~~~~~
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:20:5
+   |
+LL |     dbg!(1, 2, dbg!(3, 4));
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |     (1, 2, dbg!(3, 4));
+   |     ~~~~~~~~~~~~~~~~~~
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:21:5
+   |
+LL |     dbg!(1, 2, 3, 4, 5);
+   |     ^^^^^^^^^^^^^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |     (1, 2, 3, 4, 5);
+   |     ~~~~~~~~~~~~~~~
+
+error: aborting due to 9 previous errors
+

tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr

@@ -1,4 +1,5 @@
 error: error reading Clippy's configuration file `$DIR/clippy.toml`: unknown field `foobar`, expected one of
+           allow-dbg-in-tests
            allow-expect-in-tests
            allow-unwrap-in-tests
            allowed-scripts

tests/ui/dbg_macro.stderr

@@ -109,5 +109,38 @@ help: ensure to avoid having uses of it in version control
 LL |         2;
    |         ~
 
-error: aborting due to 10 previous errors
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:47:5
+   |
+LL |     dbg!(1);
+   |     ^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |     1;
+   |     ~
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:52:5
+   |
+LL |     dbg!(1);
+   |     ^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |     1;
+   |     ~
+
+error: `dbg!` macro is intended as a debugging tool
+  --> $DIR/dbg_macro.rs:58:9
+   |
+LL |         dbg!(1);
+   |         ^^^^^^^
+   |
+help: ensure to avoid having uses of it in version control
+   |
+LL |         1;
+   |         ~
+
+error: aborting due to 13 previous errors