python-poetry/poetry · error · RuntimeError

No lockfile found. Unable to read locked packages

Error message

No lockfile found. Unable to read locked packages

What it means

Raised by Locker._get_lock_data() when self.lock (the poetry.lock path) does not exist on disk. Poetry's solver/installer reads the lockfile to know the exact pinned package set; without it the operation cannot proceed in 'locked' mode. The error is a hard precondition check before any TOML parsing is attempted.

Source

Thrown at src/poetry/packages/locker.py:345

        if relevant_project_content:
            relevant_content["project"] = relevant_project_content
        if group_content:
            # For backwards compatibility, we must not add dependency-groups
            # if it is empty.
            relevant_content["dependency-groups"] = group_content

        if relevant_content:
            relevant_content["tool"] = {"poetry": relevant_poetry_content}
        else:
            # For backwards compatibility, we have to put the relevant content
            # of the [tool.poetry] section at top level!
            relevant_content = relevant_poetry_content

        return sha256(json.dumps(relevant_content, sort_keys=True).encode()).hexdigest()

    def _get_lock_data(self) -> dict[str, Any]:
        if not self.lock.exists():
            raise RuntimeError("No lockfile found. Unable to read locked packages")

        with self.lock.open("rb") as f:
            try:
                lock_data = tomllib.load(f)
            except tomllib.TOMLDecodeError as e:
                raise RuntimeError(f"Unable to read the lock file ({e}).")

        # if the lockfile doesn't contain a metadata section at all,
        # it probably needs to be rebuilt completely
        if "metadata" not in lock_data:
            raise RuntimeError(
                "The lock file does not have a metadata entry.\n"
                "Regenerate the lock file with the `poetry lock` command."
            )

        metadata = lock_data["metadata"]
        if "lock-version" not in metadata:
            raise RuntimeError(

View on GitHub (pinned to 92b74dcfe3)

Solutions

1. Run `poetry lock` to generate poetry.lock for the current pyproject.toml.
2. Verify you are in the project root containing pyproject.toml (the lockfile lives alongside it).
3. If the lockfile should exist, check git status / .gitignore to confirm it was committed and not deleted.
4. For install-only workflows, drop the `--locked` / `--no-update` flags that require an existing lockfile.

Example fix

// before: running in a dir with no poetry.lock
$ poetry install
RuntimeError: No lockfile found...

// after
$ poetry lock
$ poetry install

from pathlib import Path
from poetry.factory import Factory

def ensure_lockfile(project_dir: Path) -> Path:
    poetry = Factory().create_poetry(project_dir)
    lock = poetry.pyproject_path.parent / "poetry.lock"
    if not lock.exists():
        raise SystemExit(f"No poetry.lock in {project_dir}. Run `poetry lock` first.")
    return lock

When it happens

Trigger: Calling poetry install, poetry show --locked, or any command that delegates to Locker.locked_packages() / _get_lock_data() in a project directory that has a pyproject.toml but no poetry.lock file (e.g. a fresh clone, or after the lockfile was gitignored/deleted).

Common situations: Fresh checkout of a repo where poetry.lock is not committed; running install before ever running `poetry lock`; CI on a branch that removed the lockfile; wrong working directory so Poetry resolves the project root elsewhere.

Related errors

• Package {package} not found
• Unable to read the lock file ({e}).
• The lock file does not have a metadata entry. Regenerate the
• The lock file is not compatible with the current version of
• The lock file is not compatible with the current version of

AI-assisted analysis of python-poetry/poetry@92b74dcfe3 (2026-08-04). Data as JSON: /data/errors/f8ee269f5bff00a3.json. Report an issue: GitHub.