vllm.config.utils ¶

def assert_hashable(text: str) -> bool:
    if not contains_object_print(text):
        return True
    raise AssertionError(
        f"vLLM tried to hash some configs that may have Python objects ids "
        f"in them. This is a bug, please file an issue. "
        f"Text being hashed: {text}"
    )

def config(cls: ConfigT) -> ConfigT:
    """
    A decorator that ensures all fields in a dataclass have default values
    and that each field has a docstring.

    If a `ConfigT` is used as a CLI argument itself, the `type` keyword argument
    provided by `get_kwargs` will be
    `pydantic.TypeAdapter(ConfigT).validate_json(cli_arg)` which treats the
    `cli_arg` as a JSON string which gets validated by `pydantic`.

    Config validation is performed by the tools/pre_commit/validate_config.py
    script, which is invoked during the pre-commit checks.
    """
    return cls

def contains_object_print(text: str) -> bool:
    """
    Check if the text looks like a printed Python object, e.g.
    contains any substring matching the pattern: "at 0xFFFFFFF>"
    We match against 0x followed by 2-16 hex chars (there's
    a max of 16 on a 64-bit system).

    Args:
        text (str): The text to check

    Returns:
        result (bool): `True` if a match is found, `False` otherwise.
    """
    pattern = r"at 0x[a-fA-F0-9]{2,16}>"
    match = re.search(pattern, text)
    return match is not None

def get_attr_docs(cls: type[Any]) -> dict[str, str]:
    """
    Get any docstrings placed after attribute assignments in a class body.

    https://davidism.com/mit-license/
    """

    cls_node = ast.parse(textwrap.dedent(inspect.getsource(cls))).body[0]

    if not isinstance(cls_node, ast.ClassDef):
        raise TypeError("Given object was not a class.")

    out = {}

    # Consider each pair of nodes.
    for a, b in pairwise(cls_node.body):
        # Must be an assignment then a constant string.
        if (
            not isinstance(a, (ast.Assign, ast.AnnAssign))
            or not isinstance(b, ast.Expr)
            or not isinstance(b.value, ast.Constant)
            or not isinstance(b.value.value, str)
        ):
            continue

        doc = inspect.cleandoc(b.value.value)

        # An assignment can have multiple targets (a = b = v), but an
        # annotated assignment only has one target.
        targets = a.targets if isinstance(a, ast.Assign) else [a.target]

        for target in targets:
            # Must be assigning to a plain name.
            if not isinstance(target, ast.Name):
                continue

            out[target.id] = doc

    return out

def get_field(cls: ConfigType, name: str) -> Field:
    """Get the default factory field of a dataclass by name. Used for getting
    default factory fields in `EngineArgs`."""
    if not is_dataclass(cls):
        raise TypeError("The given class is not a dataclass.")
    cls_fields = {f.name: f for f in fields(cls)}
    if name not in cls_fields:
        raise ValueError(f"Field '{name}' not found in {cls.__name__}.")
    named_field: Field = cls_fields[name]
    if (default_factory := named_field.default_factory) is not MISSING:
        return field(default_factory=default_factory)
    if (default := named_field.default) is not MISSING:
        if isinstance(default, FieldInfo):
            # Handle pydantic.Field defaults
            if default.default_factory is not None:
                return field(default_factory=default.default_factory)
            else:
                default = default.default
        return field(default=default)

    raise ValueError(
        f"{cls.__name__}.{name} must have a default value or default factory."
    )

def get_hash_factors(config: ConfigT, ignored_factors: set[str]) -> dict[str, object]:
    """Gets the factors used for hashing a config class.
    - Includes all dataclass fields not in `ignored_factors`.
    - Errors on non-normalizable values.
    """
    factors: dict[str, object] = {}
    for dc_field in fields(config):
        factor = dc_field.name
        if factor in ignored_factors:
            continue
        value = getattr(config, factor, None)
        try:
            factors[factor] = normalize_value(value)
        except TypeError as e:
            raise TypeError(
                f"get_hash_factors: unsupported type for key '{factor}' "
                f"({type(value).__name__})"
            ) from e
    return factors

def getattr_iter(object: object, names: Iterable[str], default: Any) -> Any:
    """
    A helper function that retrieves an attribute from an object which may
    have multiple possible names. This is useful when fetching attributes from
    arbitrary `transformers.PretrainedConfig` instances.
    """
    for name in names:
        if hasattr(object, name):
            return getattr(object, name)
    return default

def hash_factors(items: dict[str, object]) -> str:
    """Return a SHA-256 hex digest of the canonical items structure."""
    return hashlib.sha256(json.dumps(items, sort_keys=True).encode()).hexdigest()

def is_init_field(cls: ConfigType, name: str) -> bool:
    return next(f for f in fields(cls) if f.name == name).init

def normalize_value(x):
    """Return a stable, JSON-serializable canonical form for hashing.
    Order: primitives, special types (Enum, callable, torch.dtype, Path), then
    generic containers (Mapping/Set/Sequence) with recursion.
    """
    # Fast path
    if x is None or isinstance(x, (bool, int, float, str)):
        return x

    # Enums: tag with FQN to avoid primitive collisions.
    # Ex: Enum(1) vs int(1) -> ("module.QualName", value).
    if isinstance(x, enum.Enum):
        enum_type = f"{x.__class__.__module__}.{x.__class__.__qualname__}"
        return (enum_type, normalize_value(x.value))

    # Classes (types) are accepted and canonicalized by their fully-qualified
    # name (module.qualname) for a stable identifier.
    # Instances are only accepted if they expose uuid(); otherwise they are
    # rejected to avoid under-hashing object state.

    # Callables: accept classes only; reject funcs/lambdas/methods.
    # Used by LogitsProcessor types and ModelConfig.hf_overrides.
    if isinstance(x, type):
        module = getattr(x, "__module__", "")
        qual = getattr(x, "__qualname__", getattr(x, "__name__", ""))
        return ".".join([p for p in (module, qual) if p]) or repr(x)

    # Prefer stable uuid identifiers for objects that provide them, even if
    # they are callable instances (e.g., InductorPass wrappers).
    if hasattr(x, "uuid") and callable(getattr(x, "uuid", None)):
        return x.uuid()

    if callable(x):
        raise TypeError("normalize_value: function or callable instance unsupported")

    # Torch dtype: stringify (torch.float64 -> "torch.float64").
    # We rely on the string form here; dtype-bearing fields that need additional
    # disambiguation should encode that at the config layer.
    if isinstance(x, torch.dtype):
        return str(x)

    # Bytes
    if isinstance(x, (bytes, bytearray)):
        return x.hex()

    # Paths (canonicalize)
    if isinstance(x, pathlib.Path):
        try:
            return str(x.expanduser().resolve())
        except Exception:
            return str(x)

    # Dataclasses: represent as (FQN, sorted(field,value) tuple) for stability.
    if is_dataclass(x):
        type_fqn = f"{x.__class__.__module__}.{x.__class__.__qualname__}"
        items = tuple(
            (f.name, normalize_value(getattr(x, f.name)))
            for f in sorted(fields(x), key=lambda f: f.name)
        )
        return (type_fqn, items)

    # Containers (generic)
    if isinstance(x, Mapping):
        return tuple(sorted((str(k), normalize_value(v)) for k, v in x.items()))
    if isinstance(x, Set):
        return tuple(sorted(repr(normalize_value(v)) for v in x))
    if isinstance(x, Sequence) and not isinstance(x, (str, bytes, bytearray)):
        return tuple(normalize_value(v) for v in x)

    # PretrainedConfig
    if hasattr(x, "to_json_string") and callable(x.to_json_string):
        return x.to_json_string()

    # Unsupported type: e.g., modules, generators, open files, or objects
    # without a stable JSON/UUID representation. Hard-error to avoid
    # under-hashing.
    # If you hit this, either reshape your config to use supported primitives
    # and containers, or extend normalize_value to provide a stable encoding
    # (e.g., via uuid() or to_json_string()) for this type.
    raise TypeError(
        f"normalize_value: unsupported type '{type(x).__name__}'. "
        "Ensure config values use supported primitives/containers or add a "
        "stable representation for this type."
    )

def update_config(config: ConfigT, overrides: dict[str, Any]) -> ConfigT:
    processed_overrides = {}
    for field_name, value in overrides.items():
        assert hasattr(config, field_name), (
            f"{type(config)} has no field `{field_name}`"
        )
        current_value = getattr(config, field_name)
        if is_dataclass(current_value) and not is_dataclass(value):
            assert isinstance(value, dict), (
                f"Overrides to {type(config)}.{field_name} must be a dict"
                f"  or {type(current_value)}, but got {type(value)}"
            )
            value = update_config(
                current_value,  # type: ignore[type-var]
                value,
            )
        processed_overrides[field_name] = value
    return replace(config, **processed_overrides)