python-poetry/poetry · error · ValueError

FileCache.hash_type is unknown value: '{self.hash_type}'.

Error message

FileCache.hash_type is unknown value: '{self.hash_type}'.

What it means

FileCache.__post_init__ validates that hash_type is one of the supported algorithms {md5, sha1, sha256} (cache.py:50-54, 86-90) and raises ValueError otherwise. The hash_type drives cache-key hashing and directory layout, so an unsupported value would silently corrupt cache behavior; the check fails fast instead.

Source

Thrown at src/poetry/utils/cache.py:88

        """
        return self.expires is not None and time.time() >= self.expires


@dataclasses.dataclass(frozen=True)
class FileCache(Generic[T]):
    """
    Cachy-compatible minimal file cache. Stores subsequent data in a JSON format.

    :param path: The path that the cache starts at.
    :param hash_type: The hash to use for encoding keys/building directories.
    """

    path: Path
    hash_type: str = "sha256"

    def __post_init__(self) -> None:
        if self.hash_type not in _HASHES:
            raise ValueError(
                f"FileCache.hash_type is unknown value: '{self.hash_type}'."
            )

    def get(self, key: str) -> T | None:
        return self._get_payload(key)

    def has(self, key: str) -> bool:
        """
        Determine if a file exists and has not expired in the cache.
        :param key: The cache key
        :returns: True if the key exists in the cache
        """
        return self.get(key) is not None

    def put(self, key: str, value: Any, minutes: int | None = None) -> None:
        """
        Store an item in the cache.

View on GitHub (pinned to 92b74dcfe3)

Solutions

1. Use one of the supported values: 'md5', 'sha1', or 'sha256' (default 'sha256').
2. If you need a stronger hash, note FileCache only supports these three and file hashes elsewhere are handled by the repository layer.
3. Validate the value against the allowed set before constructing FileCache.

Example fix

// before
cache = FileCache(path=cache_dir, hash_type="sha512")
// after
cache = FileCache(path=cache_dir, hash_type="sha256")

SUPPORTED_HASH_TYPES = {"md5", "sha1", "sha256"}

def is_valid_hash_type(value: str) -> bool:
    return isinstance(value, str) and value in SUPPORTED_HASH_TYPES

try:
    cache = FileCache(path=cache_dir, hash_type=hash_type)
except ValueError as e:
    if "unknown value" in str(e):
        hash_type = "sha256"
        cache = FileCache(path=cache_dir, hash_type=hash_type)
    raise

When it happens

Trigger: Constructing FileCache(path, hash_type='sha512') or any value outside {md5, sha1, sha256}; passing a typo'd algorithm name programmatically.

Common situations: Programmatic misuse of the FileCache dataclass; a config typo feeding an unsupported hash algorithm; copy-pasting code expecting sha512 support.

Related errors

• Setting {self.argument('key')} does not exist
• You can only pass one value.
• "{value}" is an invalid value for {key}
• Hash for {package} from archive {archive.name} not found in
• The name [pypi] is reserved for repositories

AI-assisted analysis of python-poetry/poetry@92b74dcfe3 (2026-08-04). Data as JSON: /data/errors/03af7b913cb55dcc.json. Report an issue: GitHub.