Enhance robustness of CVS processing ,Fix potential CSV parsing issues

- Add CSV quoting for all fields
- Remove null characters from CSV input
- Improve CSV data integrity
- Ensure consistent CSV formatting

lightrag/utils.py

@@ -237,13 +237,13 @@ def truncate_list_by_token_size(list_data: list, key: callable, max_token_size:
 
 def list_of_list_to_csv(data: List[List[str]]) -> str:
     output = io.StringIO()
-    writer = csv.writer(output)
+    writer = csv.writer(output, quoting=csv.QUOTE_ALL)
     writer.writerows(data)
     return output.getvalue()
 
 
 def csv_string_to_list(csv_string: str) -> List[List[str]]:
-    output = io.StringIO(csv_string)
+    output = io.StringIO(csv_string.replace('\x00', ''))
     reader = csv.reader(output)
     return [row for row in reader]