From 2ae9f5367a99342d1603bc98e60b0f31a27831a6 Mon Sep 17 00:00:00 2001
From: Xianpeng Shen <3353385+shenxianpeng@users.noreply.github.com>
Date: Tue, 10 Nov 2026 06:31:24 +0000
Subject: [PATCH] fix: don't drop clang-tidy diagnostics when colors are on

If `.clang-tidy` sets `UseColor: true`, clang-tidy prints ANSI color
codes even when piped, so no line matched NOTE_HEADER and every
diagnostic was dropped. Strip the codes from each line before parsing.

Fixes #560
---
 cpp-linter/src/clang_tools/clang_tidy/mod.rs  | 11 ++++--
 cpp-linter/src/clang_tools/clang_tidy/test.rs | 36 +++++++++++++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/cpp-linter/src/clang_tools/clang_tidy/mod.rs b/cpp-linter/src/clang_tools/clang_tidy/mod.rs
index cc49ae54..ec6c21a7 100644
--- a/cpp-linter/src/clang_tools/clang_tidy/mod.rs
+++ b/cpp-linter/src/clang_tools/clang_tidy/mod.rs
@@ -182,6 +182,11 @@ impl TidyAdvice {
 /// A regex pattern to capture the clang-tidy note header.
 const NOTE_HEADER: &str = r"^(.+):(\d+):(\d+):\s(\w+):(.*)\[([a-zA-Z\d\-\.]+),?[^\]]*\]$";
 
+/// A regex pattern to match ANSI color codes.
+///
+/// clang-tidy emits them even when piped if `.clang-tidy` sets `UseColor: true`.
+const ANSI_ESCAPE: &str = r"\x1b\[[0-9;]*m";
+
 /// Parses clang-tidy stdout.
 ///
 /// Here it helps to have the JSON database deserialized for normalizing paths present
@@ -192,6 +197,7 @@ fn parse_tidy_output(
     repo_root: &Path,
 ) -> Result<Vec<TidyNotification>, ClangCaptureError> {
     let note_header = Regex::new(NOTE_HEADER)?;
+    let ansi_escape = Regex::new(ANSI_ESCAPE)?;
     let mut notification = None;
     let mut result = Vec::new();
     for line in String::from_utf8(tidy_stdout.to_vec())
@@ -201,7 +207,8 @@ fn parse_tidy_output(
         })?
         .lines()
     {
-        if let Some(captured) = note_header.captures(line) {
+        let line = ansi_escape.replace_all(line, "");
+        if let Some(captured) = note_header.captures(&line) {
             // First check that the diagnostic name is a actual diagnostic name.
             // Sometimes clang-tidy uses square brackets to enclose additional context
             // about the diagnostic rationale. For example: '[with auto = typename ...]'
@@ -267,7 +274,7 @@ fn parse_tidy_output(
         } else if let Some(note) = &mut notification {
             // append lines of code that are part of
             // the previous line's notification
-            note.suggestion.push(line.to_string());
+            note.suggestion.push(line.into_owned());
         }
     }
     if let Some(note) = notification {
diff --git a/cpp-linter/src/clang_tools/clang_tidy/test.rs b/cpp-linter/src/clang_tools/clang_tidy/test.rs
index 32bd57e0..4aa71e22 100644
--- a/cpp-linter/src/clang_tools/clang_tidy/test.rs
+++ b/cpp-linter/src/clang_tools/clang_tidy/test.rs
@@ -223,6 +223,42 @@ TrenchBroom/TrenchBroom/common/test/src/mdl/tst_ReadFreeImageTexture.cpp:44:48:
     }
 }
 
+#[test]
+fn parse_colored_tidy_output() {
+    // clang-tidy 18 output when `.clang-tidy` sets `UseColor: true`
+    // cspell:ignore mwarning mvariable mnote deadcode
+    let tidy_out = concat!(
+        "\x1b[1ma.cpp:1:17: \x1b[0m\x1b[0;1;35mwarning: \x1b[0m\x1b[1mvariable name 'x' is too short, expected at least 3 characters [readability-identifier-length]\x1b[0m\n",
+        "    1 | int main(){ int x = 0; x = 1; return 0; }\x1b[0m\n",
+        "      | \x1b[0;1;32m                ^\n",
+        "\x1b[0m\x1b[1ma.cpp:1:24: \x1b[0m\x1b[0;1;35mwarning: \x1b[0m\x1b[1mValue stored to 'x' is never read [clang-analyzer-deadcode.DeadStores]\x1b[0m\n",
+        "    1 | int main(){ int x = 0; x = 1; return 0; }\x1b[0m\n",
+        "      | \x1b[0;1;32m                       ^   ~\n",
+        "\x1b[0m\x1b[1ma.cpp:1:24: \x1b[0m\x1b[0;1;36mnote: \x1b[0mValue stored to 'x' is never read\x1b[0m\n",
+        "    1 | int main(){ int x = 0; x = 1; return 0; }\x1b[0m\n",
+        "      | \x1b[0;1;32m                       ^   ~\n",
+        "\x1b[0m\n",
+    );
+    let notes = parse_tidy_output(tidy_out.as_bytes(), &None, &PathBuf::from(".")).unwrap();
+    let diagnostics = notes
+        .iter()
+        .map(|n| n.diagnostic.as_str())
+        .collect::<Vec<_>>();
+    assert_eq!(
+        diagnostics,
+        [
+            "readability-identifier-length",
+            "clang-analyzer-deadcode.DeadStores"
+        ]
+    );
+    assert_eq!(notes[0].filename, "a.cpp");
+    assert_eq!((notes[1].line, notes[1].cols), (1, 24));
+    for note in &notes {
+        assert!(!note.rationale.contains('\x1b'));
+        assert!(note.suggestion.iter().all(|l| !l.contains('\x1b')));
+    }
+}
+
 fn dummy_note(filename: &str, fixed_lines: Vec<u32>) -> TidyNotification {
     TidyNotification {
         filename: filename.to_string(),