pypa/pip · error · MetadataInvalid

Requested {self.ireq} has invalid metadata: {self.error}

Error message

Requested {self.ireq} has invalid metadata: {self.error}

What it means

_check_metadata_consistency (candidates.py:238-241) parses the distribution's Requires-Dist entries via iter_dependencies; if any dependency string raises InvalidRequirement, pip wraps it as MetadataInvalid. The package's own metadata violates PEP 508 requirement syntax.

Source

Thrown at src/pip/_internal/resolution/resolvelib/candidates.py:241

                self._ireq,
                "name",
                self._name,
                dist.canonical_name,
            )
        if self._version is not None and self._version != dist.version:
            raise MetadataInconsistent(
                self._ireq,
                "version",
                str(self._version),
                str(dist.version),
            )
        # check dependencies are valid
        # TODO performance: this means we iterate the dependencies at least twice,
        # we may want to cache parsed Requires-Dist
        try:
            list(dist.iter_dependencies(list(dist.iter_provided_extras())))
        except InvalidRequirement as e:
            raise MetadataInvalid(self._ireq, str(e))

    def _prepare(self) -> BaseDistribution:
        try:
            dist = self._prepare_distribution()
        except HashError as e:
            # Provide HashError the underlying ireq that caused it. This
            # provides context for the resulting error message to show the
            # offending line to the user.
            e.req = self._ireq
            raise
        except InstallationSubprocessError as exc:
            if isinstance(self._ireq.comes_from, InstallRequirement):
                request_chain = self._ireq.comes_from.from_path()
            else:
                request_chain = self._ireq.comes_from

            if request_chain is None:
                request_chain = "directly requested"

View on GitHub (pinned to f399c37189)

Solutions

1. Report the malformed metadata to the package maintainer.
2. Pin to a version of the package known to have valid metadata.
3. Fork/rebuild the package with corrected METADATA and install from your fixed source.

# Validate a wheel's Requires-Dist entries parse as PEP 508 before install.
import zipfile, sys
from packaging.requirements import Requirement, InvalidRequirement
whl = sys.argv[1]
with zipfile.ZipFile(whl) as z:
    meta = [n for n in z.namelist() if n.endswith("METADATA")][0]
    for line in z.read(meta).decode().splitlines():
        if line.startswith("Requires-Dist:"):
            spec = line.split(":", 1)[1].strip()
            try:
                Requirement(spec)
            except InvalidRequirement as e:
                print(f"INVALID Requires-Dist in {whl}: {spec!r} ({e})")

When it happens

Trigger: Installing a package whose METADATA contains a malformed Requires-Dist value (invalid PEP 508 specifier syntax), detected during candidate preparation.

Common situations: Upstream packaging bug; a hand-edited METADATA; a very old package using non-standard dependency notation.

Related errors

• Requested {ireq} has invalid metadata: Requires-Dist in {sou
• Invalid requirement: {req_string!r}: {exc}
• invalid-installed-package
• Index {link.comes_from} does not provide upload-time metadat
• Bad metadata in {dist} (invalid metadata entry 'name')

AI-assisted analysis of pypa/pip@f399c37189 (2026-08-08). Data as JSON: /api/errors/3f60a3677322b2a4. Report an issue: GitHub.