def raise_if_valid_subsets_unintentionally_ignored(train_cfg) -> None:
    """Raises if there are paths matching 'valid*[0-9].*' which are not combined or ignored."""
    if (
        train_cfg.dataset.ignore_unused_valid_subsets
        or train_cfg.dataset.combine_valid_subsets
        or train_cfg.dataset.disable_validation
        or not hasattr(train_cfg.task, "data")
    ):
        return
    other_paths = _find_extra_valid_paths(train_cfg.task.data)
    specified_subsets = train_cfg.dataset.valid_subset.split(",")
    ignored_paths = [p for p in other_paths if p not in specified_subsets]
    if ignored_paths:
        advice = "Set --combine-val to combine them or --ignore-unused-valid-subsets to ignore them."
        msg = f"Valid paths {ignored_paths} will be ignored. {advice}"
        raise ValueError(msg)
Raises if there are paths matching 'valid*[0-9].*' which are not combined or ignored.
fairseq/data/data_utils.py