Merge pull request #715 from epage/fuzz

fix(parser): Ensure error spans are valid for escape sequences

Author: epage

crates/toml_edit/src/error.rs

@@ -26,6 +26,11 @@ impl TomlError {
         let raw = String::from_utf8(raw.to_owned()).expect("original document was utf8");
 
         let offset = error.offset();
+        let offset = (0..=offset)
+            .rev()
+            .find(|index| raw.is_char_boundary(*index))
+            .unwrap_or(0);
+
         let mut indices = raw[offset..].char_indices();
         indices.next();
         let len = if let Some((index, _)) = indices.next() {

crates/toml_edit/tests/testsuite/invalid.rs

@@ -227,3 +227,12 @@ fn text_error_span() {
     let actual = &input[err.span().unwrap()];
     assert_eq!(actual, "");
 }
+
+#[test]
+fn fuzzed_68144_error_span() {
+    let input = "\"\\ᾂr\"";
+    let err = input.parse::<toml_edit::DocumentMut>().unwrap_err();
+    dbg!(err.span());
+    let actual = &input[err.span().unwrap()];
+    assert_eq!(actual, "ᾂ");
+}