Make next_cursor extraction logic even more robust (ref #1407) (#1409)

Author: seratch

slack_sdk/web/internal_utils.py

@@ -230,9 +230,10 @@ def _next_cursor_is_present(data) -> bool:
         A boolean value.
     """
     # Only admin.conversations.search returns next_cursor at the top level
-    present = ("next_cursor" in data and data["next_cursor"] != "") or (
+    present = ("next_cursor" in data and data["next_cursor"] is not None and data["next_cursor"] != "") or (
         "response_metadata" in data
         and "next_cursor" in data["response_metadata"]
+        and data["response_metadata"]["next_cursor"] is not None
         and data["response_metadata"]["next_cursor"] != ""
     )
     return present

tests/slack_sdk/web/test_internal_utils.py

@@ -11,6 +11,7 @@
     _build_unexpected_body_error_message,
     _parse_web_class_objects,
     _to_v2_file_upload_item,
+    _next_cursor_is_present,
 )
 
 
@@ -98,3 +99,12 @@ def test_files_upload_v2_issue_1356(self):
         assert file_io_item.get("filename") == "Uploaded file"
         file_io_item = _to_v2_file_upload_item({"file": file_io, "filename": "foo.txt"})
         assert file_io_item.get("filename") == "foo.txt"
+
+    def test_next_cursor_is_present(self):
+        assert _next_cursor_is_present({"next_cursor": "next-page"}) is True
+        assert _next_cursor_is_present({"next_cursor": ""}) is False
+        assert _next_cursor_is_present({"next_cursor": None}) is False
+        assert _next_cursor_is_present({"response_metadata": {"next_cursor": "next-page"}}) is True
+        assert _next_cursor_is_present({"response_metadata": {"next_cursor": ""}}) is False
+        assert _next_cursor_is_present({"response_metadata": {"next_cursor": None}}) is False
+        assert _next_cursor_is_present({"something_else": {"next_cursor": "next-page"}}) is False