python-poetry/poetry · error · RuntimeError

Unable to retrieve the package version for {name}

Error message

Unable to retrieve the package version for {name}

What it means

Raised by PackageInfo.to_package() at src/poetry/inspection/info.py:135-138 when the version field is falsy. Version is mandatory for a Package, so Poetry aborts with RuntimeError rather than silently using '0.0.0'.

Source

Thrown at src/poetry/inspection/info.py:138

        """
        Create a new `poetry.core.packages.package.Package` instance using metadata from
        this instance.

        :param name: Name to use for the package, if not specified name from this
            instance is used.
        :param extras: Extras to activate for this package.
        :param root_dir:  Optional root directory to use for the package. If set,
            dependency strings will be parsed relative to this directory.
        """
        name = name or self.name

        if not name:
            raise RuntimeError(f"Unable to create package with no name for {root_dir}")

        if not self.version:
            # The version could not be determined, so we raise an error since it is
            # mandatory.
            raise RuntimeError(f"Unable to retrieve the package version for {name}")

        package = Package(
            name=name,
            version=self.version,
            source_type=self._source_type,
            source_url=self._source_url,
            source_reference=self._source_reference,
            yanked=self.yanked,
        )
        if self.summary is not None:
            package.description = self.summary
        package.root_dir = root_dir
        package.python_versions = self.requires_python or "*"
        package.files = self.files

        # If this is a local poetry project, we can extract "richer" requirement
        # information, eg: development requirements etc.
        if root_dir is not None:

View on GitHub (pinned to 92b74dcfe3)

Solutions

1. Ensure the inspected package's metadata exposes a concrete Version (set version in pyproject.toml [project] or pass it explicitly in setup.py).
2. If using dynamic versioning, confirm the build backend (e.g. setuptools-git-versioning) actually produces a version at build time.
3. Rebuild the artifact and verify with `python -m pkginfo ./dist/*.whl` that version is populated.

Example fix

# before
[project]
name = "my_pkg"
# no version, no dynamic

# after
[project]
name = "my_pkg"
version = "0.1.0"

from poetry.inspection.info import PackageInfo

info = PackageInfo.from_path(path)
if not info.version:
    raise ValueError(f'No version in metadata for {info.name or path}; refusing to convert.')
pkg = info.to_package(root_dir=path)

def has_version(info: PackageInfo) -> bool:
    return bool(getattr(info, 'version', None))

try:
    pkg = PackageInfo.from_path(path).to_package(root_dir=path)
except RuntimeError as e:
    if 'retrieve the package version' in str(e):
        raise ValueError(f'Invalid package at {path}: missing version') from e
    raise

When it happens

Trigger: Inspecting a distribution whose metadata has no Version field, or whose version is empty/None. Triggered through PackageInfo.from_path/from_directory → to_package(), e.g. during `poetry add` or dependency resolution on a local package.

Common situations: A local package with dynamic versioning that didn't resolve at inspection time (PEP 621 `dynamic = ["version"]` without a backend that fills it), a hand-built sdist missing the Version header, or a legacy setup.py without version.

Related errors

• Unable to create package with no name for {root_dir}
• Unknown metadata version: {dist.metadata_version}
• Unable to determine package info from path: {file_path}
• Invalid author string. Must be in the format: John Smith <jo
• Invalid version constraint: {constraint}

AI-assisted analysis of python-poetry/poetry@92b74dcfe3 (2026-08-04). Data as JSON: /data/errors/f45b59dc7d3b1086.json. Report an issue: GitHub.