nodejs/node · error · ExceptionGroup
invalid or unparsed metadata
Error message
invalid or unparsed metadata
What it means
A re-wrapping ExceptionGroup raised by Metadata.from_email after it has already checked for unparsed headers: when the subsequent cls.from_raw(raw, validate=validate) itself raises an ExceptionGroup (the 'invalid metadata' group), it is caught and re-raised with the broader message 'invalid or unparsed metadata', discarding the original cause via 'from None'.
Solutions
- Catch ExceptionGroup and read .exceptions to identify the failing raw fields.
- Correct the offending field values in the source METADATA/PKG-INFO.
- Pass validate=False to from_email to skip raw validation entirely.
Example fix
# before
meta = Metadata.from_email(data, validate=True)
# after
try:
meta = Metadata.from_email(data, validate=True)
except ExceptionGroup as eg:
for sub in eg.exceptions:
print(sub)
raise Defensive patterns
Strategy: try-catch
Try / catch
try:
meta = Metadata.from_email(data, validate=True)
except ExceptionGroup as eg:
for sub in eg.exceptions:
# sub is InvalidMetadata with .field; fix source accordingly
pass Prevention
- Validate field values (versions, names) before they reach metadata emission.
- Keep the packaging library version current with the core-metadata spec you target.
- Use validate=False for read-only inspection when strictness is not required.
When it happens
Trigger: Calling Metadata.from_email(data, validate=True) where headers parsed cleanly into raw fields but one or more of those fields then fails raw-level validation inside from_raw. The inner 'invalid metadata' group is rebranded and re-raised here.
Common situations: A well-formed email whose field values are invalid (e.g. a Version header that is not PEP 440 compliant, or a name that fails canonicalization). The from None hides the original traceback chain, so the developer sees only this top-level group.
Related errors
AI-assisted analysis of nodejs/node@1b2de5e052 (2026-08-13).
Data as JSON: /api/errors/207e130b4128a272.
Report an issue: GitHub.
Appendix: source
Thrown at tools/gyp/pylib/packaging/metadata.py:732
"""
raw, unparsed = parse_email(data)
if validate:
exceptions: list[Exception] = []
for unparsed_key in unparsed:
if unparsed_key in _EMAIL_TO_RAW_MAPPING:
message = f"{unparsed_key!r} has invalid data"
else:
message = f"unrecognized field: {unparsed_key!r}"
exceptions.append(InvalidMetadata(unparsed_key, message))
if exceptions:
raise ExceptionGroup("unparsed", exceptions)
try:
return cls.from_raw(raw, validate=validate)
except ExceptionGroup as exc_group:
raise ExceptionGroup(
"invalid or unparsed metadata", exc_group.exceptions
) from None
metadata_version: _Validator[_MetadataVersion] = _Validator()
""":external:ref:`core-metadata-metadata-version`
(required; validated to be a valid metadata version)"""
name: _Validator[str] = _Validator()
""":external:ref:`core-metadata-name`
(required; validated using :func:`~packaging.utils.canonicalize_name` and its
*validate* parameter)"""
version: _Validator[version_module.Version] = _Validator()
""":external:ref:`core-metadata-version` (required)"""
dynamic: _Validator[Optional[List[str]]] = _Validator(
added="2.2",
)
""":external:ref:`core-metadata-dynamic`
(validated against core metadata field names and lowercased)"""
platforms: _Validator[Optional[List[str]]] = _Validator()View on GitHub (pinned to 1b2de5e052)