From dee67205deb42f4fd1c8ff4d2ea99f1b5e575688 Mon Sep 17 00:00:00 2001
From: Dhruv Manilawala <dhruvmanila@gmail.com>
Date: Tue, 18 Jun 2024 15:45:07 +0530
Subject: [PATCH] Avoid adding `noqa` comment for syntax error

---
 crates/ruff_linter/src/noqa.rs | 40 +++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/crates/ruff_linter/src/noqa.rs b/crates/ruff_linter/src/noqa.rs
index dae0b0cf66651..51fc4596d7b3c 100644
--- a/crates/ruff_linter/src/noqa.rs
+++ b/crates/ruff_linter/src/noqa.rs
@@ -726,6 +726,12 @@ fn find_noqa_comments<'a>(
 
     // Mark any non-ignored diagnostics.
     for diagnostic in diagnostics {
+        // Syntax errors cannot be ignored by a `noqa` comment so we shouldn't add them either.
+        if diagnostic.kind.rule() == Rule::SyntaxError {
+            comments_by_line.push(None);
+            continue;
+        }
+
         match &exemption {
             FileExemption::All(_) => {
                 // If the file is exempted, don't add any noqa directives.
@@ -1063,7 +1069,7 @@ mod tests {
 
     use crate::generate_noqa_edits;
     use crate::noqa::{add_noqa_inner, Directive, NoqaMapping, ParsedFileExemption};
-    use crate::rules::pycodestyle::rules::AmbiguousVariableName;
+    use crate::rules::pycodestyle::rules::{AmbiguousVariableName, UselessSemicolon};
     use crate::rules::pyflakes::rules::UnusedVariable;
     use crate::rules::pyupgrade::rules::PrintfStringFormatting;
 
@@ -1380,4 +1386,36 @@ print(
             ))]
         );
     }
+
+    #[test]
+    fn syntax_error() {
+        let path = Path::new("/tmp/foo.txt");
+        let source = "\
+foo;
+bar =
+";
+        let diagnostics = [Diagnostic::new(
+            UselessSemicolon,
+            TextRange::new(4.into(), 5.into()),
+        )];
+        let noqa_line_for = NoqaMapping::default();
+        let comment_ranges = CommentRanges::default();
+        let edits = generate_noqa_edits(
+            path,
+            &diagnostics,
+            &Locator::new(source),
+            &comment_ranges,
+            &[],
+            &noqa_line_for,
+            LineEnding::Lf,
+        );
+        assert_eq!(
+            edits,
+            vec![Some(Edit::replacement(
+                "  # noqa: E703\n".to_string(),
+                4.into(),
+                5.into()
+            ))]
+        );
+    }
 }