Fix pagination issue in JSONResponseCursorPaginator with empty stri…

…ng cursor value

Adjusts the `update_state()` method to set `_next_reference` to None
when the cursor value extracted from the JSON response is an empty
string, preventing unintended pagination requests.

Fixed #2012

dlt/sources/helpers/rest_client/paginators.py

@@ -651,7 +651,7 @@ def __init__(
     def update_state(self, response: Response, data: Optional[List[Any]] = None) -> None:
         """Extracts the cursor value from the JSON response."""
         values = jsonpath.find_values(self.cursor_path, response.json())
-        self._next_reference = values[0] if values else None
+        self._next_reference = values[0] if values and values[0] else None
 
     def update_request(self, request: Request) -> None:
         """Updates the request with the cursor query parameter."""

tests/sources/helpers/rest_client/test_paginators.py

@@ -530,6 +530,12 @@ def test_update_state(self):
         assert paginator._next_reference == "cursor-2"
         assert paginator.has_next_page is True
 
+    def test_update_state_when_cursor_path_is_empty_string(self):
+        paginator = JSONResponseCursorPaginator(cursor_path="next_cursor")
+        response = Mock(Response, json=lambda: {"next_cursor": "", "results": []})
+        paginator.update_state(response)
+        assert paginator.has_next_page is False
+
     def test_update_request(self):
         paginator = JSONResponseCursorPaginator(cursor_path="next_cursor")
         paginator._next_reference = "cursor-2"