fix unescaped '"' in json writing

src/io/json/write/serialize.rs

@@ -139,15 +139,15 @@ fn list_serializer<'a, O: Offset>(
 
 #[inline]
 fn utf8_serialize(value: &str, buf: &mut Vec<u8>) {
-    if value.as_bytes().is_ascii() {
+    if value.as_bytes().is_ascii() && !value.contains('"') {
         buf.reserve(value.len() + 2);
         buf.push(b'"');
         buf.extend_from_slice(value.as_bytes());
         buf.push(b'"');
     } else {
         // it may contain reserved keywords: perform roundtrip for
         // todo: avoid this roundtrip over serde_json
-        serde_json::to_writer(buf, &Value::String(value.to_string())).unwrap();
+        serde_json::to_writer(buf, value).unwrap();
     }
 }
 

tests/it/io/json/write.rs

@@ -305,3 +305,22 @@ fn write_escaped_utf8() -> Result<()> {
     );
     Ok(())
 }
+
+#[test]
+fn write_quotation_marks_in_utf8() -> Result<()> {
+    let a = Utf8Array::<i32>::from(&vec![Some("a\"a"), None]);
+
+    let batch = Chunk::try_new(vec![&a as &dyn Array]).unwrap();
+
+    let buf = write_batch(
+        batch,
+        vec!["c1".to_string()],
+        json_write::LineDelimited::default(),
+    )?;
+
+    assert_eq!(
+        String::from_utf8(buf).unwrap().as_bytes(),
+        b"{\"c1\":\"a\\\"a\"}\n{\"c1\":null}\n"
+    );
+    Ok(())
+}