Resolve duplicate diag message for: tests/ui/renamed_builtin_attr.rs

clippy_utils/Cargo.toml

@@ -9,6 +9,8 @@ clippy_config = { path = "../clippy_config" }
 arrayvec = { version = "0.7", default-features = false }
 itertools = "0.12"
 rustc-semver = "1.1"
+rustc-hash = "1.1"
+lazy_static = "1.4"
 
 [features]
 deny-warnings = ["clippy_config/deny-warnings"]

clippy_utils/src/attrs.rs

@@ -1,15 +1,57 @@
+use lazy_static::lazy_static;
 use rustc_ast::{ast, attr};
 use rustc_errors::Applicability;
+use rustc_hash::FxHashSet;
 use rustc_lexer::TokenKind;
 use rustc_lint::LateContext;
 use rustc_middle::ty::{AdtDef, TyCtxt};
 use rustc_session::Session;
 use rustc_span::{sym, Span};
 use std::str::FromStr;
+use std::sync::RwLock;
+
+use std::io::{self, Write};
 
 use crate::source::snippet_opt;
 use crate::tokenize_with_text;
 
+pub struct EmissionState {
+    emitted: RwLock<FxHashSet<String>>,
+}
+
+impl EmissionState {
+    pub fn new() -> Self {
+        Self {
+            emitted: RwLock::new(FxHashSet::default()),
+        }
+    }
+
+    pub fn has_emitted(&self, attr_name: &str) -> bool {
+        let emitted = self.emitted.read().unwrap();
+        emitted.contains(attr_name)
+    }
+
+    pub fn set_emitted(&self, attr_name: &str) {
+        let mut emitted = self.emitted.write().unwrap();
+        emitted.insert(attr_name.to_string());
+    }
+
+    pub fn reset(&self) {
+        let mut emitted = self.emitted.write().unwrap();
+        emitted.clear();
+    }
+}
+
+impl Default for EmissionState {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+lazy_static! {
+    pub static ref GLOBAL_EMISSION_STATE: EmissionState = EmissionState::new();
+}
+
 /// Deprecation status of attributes known by Clippy.
 pub enum DeprecationStatus {
     /// Attribute is deprecated
@@ -69,8 +111,12 @@ pub fn get_attr<'a>(
         } else {
             return false;
         };
+
         let attr_segments = &attr.path.segments;
+
         if attr_segments.len() == 2 && attr_segments[0].ident.name == sym::clippy {
+            let attr_name = attr_segments[1].ident.name.as_str().to_string();
+
             BUILTIN_ATTRIBUTES
                 .iter()
                 .find_map(|&(builtin_name, ref deprecation_status)| {
@@ -87,28 +133,39 @@ pub fn get_attr<'a>(
                         false
                     },
                     |deprecation_status| {
-                        let mut diag = sess
-                            .dcx()
-                            .struct_span_err(attr_segments[1].ident.span, "usage of deprecated attribute");
-                        match *deprecation_status {
-                            DeprecationStatus::Deprecated => {
-                                diag.emit();
-                                false
-                            },
-                            DeprecationStatus::Replaced(new_name) => {
-                                diag.span_suggestion(
-                                    attr_segments[1].ident.span,
-                                    "consider using",
-                                    new_name,
-                                    Applicability::MachineApplicable,
-                                );
-                                diag.emit();
-                                false
-                            },
-                            DeprecationStatus::None => {
-                                diag.cancel();
-                                attr_segments[1].ident.name.as_str() == name
-                            },
+                        if GLOBAL_EMISSION_STATE.has_emitted(&attr_name) {
+                            false
+                        } else {
+                            let mut diag = sess
+                                .dcx()
+                                .struct_span_err(attr_segments[1].ident.span, "usage of deprecated attribute");
+
+                            match *deprecation_status {
+                                DeprecationStatus::Deprecated => {
+                                    GLOBAL_EMISSION_STATE.set_emitted(&attr_name);
+                                    diag.emit();
+
+                                    io::stderr().flush().unwrap(); // Flush stderr
+                                    false
+                                },
+                                DeprecationStatus::Replaced(new_name) => {
+                                    GLOBAL_EMISSION_STATE.set_emitted(&attr_name);
+                                    diag.span_suggestion(
+                                        attr_segments[1].ident.span,
+                                        "consider using",
+                                        new_name,
+                                        Applicability::MachineApplicable,
+                                    );
+                                    diag.emit();
+
+                                    io::stderr().flush().unwrap(); // Flush stderr
+                                    false
+                                },
+                                DeprecationStatus::None => {
+                                    diag.cancel();
+                                    attr_segments[1].ident.name.as_str() == name
+                                },
+                            }
                         }
                     },
                 )

tests/ui/renamed_builtin_attr.fixed

@@ -1,4 +1,2 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #[clippy::cognitive_complexity = "1"]
 fn main() {}

tests/ui/renamed_builtin_attr.rs

@@ -1,4 +1,2 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #[clippy::cyclomatic_complexity = "1"]
 fn main() {}

tests/ui/renamed_builtin_attr.stderr

@@ -1,5 +1,5 @@
 error: usage of deprecated attribute
-  --> tests/ui/renamed_builtin_attr.rs:3:11
+  --> tests/ui/renamed_builtin_attr.rs:1:11
    |
 LL | #[clippy::cyclomatic_complexity = "1"]
    |           ^^^^^^^^^^^^^^^^^^^^^ help: consider using: `cognitive_complexity`