Function validate_field_metas

python/pyfory/field.py:230–270

Validate field metadata for a dataclass. Checks: - Tag IDs are unique (no duplicate IDs >= 0) - Optional[T] fields have nullable=True Args: cls: The dataclass type. field_metas: Dict mapping field name to ForyFieldMeta. type_hints: Dict mapping field na

(
    cls: type,
    field_metas: Dict[str, ForyFieldMeta],
    type_hints: Dict[str, type],
)

def validate_field_metas(
    cls: type,
    field_metas: Dict[str, ForyFieldMeta],
    type_hints: Dict[str, type],
) -> None:
    """
    Validate field metadata for a dataclass.

    Checks:
    - Tag IDs are unique (no duplicate IDs >= 0)
    - Optional[T] fields have nullable=True

    Args:
        cls: The dataclass type.
        field_metas: Dict mapping field name to ForyFieldMeta.
        type_hints: Dict mapping field name to type hint.

    Raises:
        ValueError: If validation fails.
    """
    from pyfory.type_util import is_optional_type

    # Check tag ID uniqueness
    tag_ids_seen: Dict[int, str] = {}
    for field_name, meta in field_metas.items():
        if meta.id >= 0:
            if meta.id in tag_ids_seen:
                raise ValueError(
                    f"Duplicate tag ID {meta.id} in class {cls.__name__}: fields '{tag_ids_seen[meta.id]}' and '{field_name}' have the same ID"
                )
            tag_ids_seen[meta.id] = field_name

    # Check nullable consistency with Optional types
    for field_name, meta in field_metas.items():
        if field_name not in type_hints:
            continue
        type_hint = type_hints[field_name]
        if is_optional_type(type_hint) and not meta.nullable:
            raise ValueError(
                f"Field '{field_name}' in class {cls.__name__} is Optional[T] but nullable=False. Optional fields must have nullable=True."
            )