pypa/pip · error · NoneMetadataError

None {metadata_name} metadata found for distribution: {dist}

Error message

None {metadata_name} metadata found for distribution: {dist}

What it means

NoneMetadataError raised by _check_requires_python in the legacy resolver when reading the distribution's metadata raises FileNotFoundError — i.e. there is no METADATA/PKG-INFO file at all for the distribution. Without metadata pip cannot read Requires-Python (or anything else), so it cannot decide compatibility and surfaces the underlying file error.

Source

Thrown at src/pip/_internal/resolution/legacy/resolver.py:80

    """
    Check whether the given Python version is compatible with a distribution's
    "Requires-Python" value.

    :param version_info: A 3-tuple of ints representing the Python
        major-minor-micro version to check.
    :param ignore_requires_python: Whether to ignore the "Requires-Python"
        value if the given Python version isn't compatible.

    :raises UnsupportedPythonVersion: When the given Python version isn't
        compatible.
    """
    # This idiosyncratically converts the SpecifierSet to str and let
    # check_requires_python then parse it again into SpecifierSet. But this
    # is the legacy resolver so I'm just not going to bother refactoring.
    try:
        requires_python = str(dist.requires_python)
    except FileNotFoundError as e:
        raise NoneMetadataError(dist, str(e))
    try:
        is_compatible = check_requires_python(
            requires_python,
            version_info=version_info,
        )
    except specifiers.InvalidSpecifier as exc:
        logger.warning(
            "Package %r has an invalid Requires-Python: %s", dist.raw_name, exc
        )
        return

    if is_compatible:
        return

    version = ".".join(map(str, version_info))
    if ignore_requires_python:
        logger.debug(
            "Ignoring failed Requires-Python check for package %r: %s not in %r",

View on GitHub (pinned to d7d0d0a394)

Solutions

1. Clear the pip cache: 'pip cache purge' (and remove ~/.cache/pip or the build dir).
2. Upgrade to the new resolver if possible (drop '--use-legacy-resolver') so the failure surfaces more cleanly.
3. Re-download or rebuild the offending distribution; verify its .dist-info contains METADATA.
4. If the package on the index is broken, pin a known-good version with 'pkg==X.Y.Z'.

Example fix

# before
pip install --use-legacy-resolver broken-pkg   # NoneMetadataError

# after
pip cache purge
pip install broken-pkg   # new resolver; or pin a known-good version

def distribution_has_metadata(dist) -> bool:
    try:
        _ = dist.requires_python
        return True
    except FileNotFoundError:
        return False

def has_metadata_file(dist_info_dir: str) -> bool:
    import os
    return os.path.isfile(os.path.join(dist_info_dir, 'METADATA'))

from pip._internal.exceptions import NoneMetadataError
try:
    run_pip(['install', '--use-legacy-resolver', 'pkg'])
except NoneMetadataError:
    run_pip(['cache', 'purge'])
    run_pip(['install', 'pkg'])   # or pin a known-good version

When it happens

Trigger: Legacy resolver ('--use-feature=no use of new resolver' off, or '--legacy-resolver') processing a distribution whose .dist-info/METADATA is missing from the index/cache, or whose extracted source has no metadata file. dist.requires_python access triggers FileNotFoundError.

Common situations: Corrupted pip cache; partially-downloaded distribution; a malformed package on an index; filesystem issue removing the metadata file; an old sdist that fails to generate metadata.

Related errors

• {path} is a symlink; Will not return uid for symlinks
• venv-creation-error
• Too many arguments
• Please provide a pattern
• Can not open an editor for a file name containing " {fname}

AI-assisted analysis of pypa/pip@d7d0d0a394 (2026-08-04). Data as JSON: /data/errors/47a343b1a614ea51.json. Report an issue: GitHub.