pypa/pip · error · InstallationError

not found. Cannot resolve '--group' option.

Error message

{path} not found. Cannot resolve '--group' option.

What it means

The pyproject.toml file path specified for '--group' resolution does not exist on the filesystem. The _load_pyproject helper caught a FileNotFoundError and converted it to an InstallationError with a clear message.

Solutions

1. Verify the file exists: 'ls pyproject.toml' or 'ls /path/to/pyproject.toml'
2. Run pip from the project root directory where pyproject.toml lives
3. Create a pyproject.toml if your project does not have one

import os

def pyproject_exists(path: str) -> bool:
    return os.path.isfile(path)

if not pyproject_exists("pyproject.toml"):
    print("pyproject.toml not found — create it or check the path")

import os

def pyproject_file_exists(path: str) -> bool:
    """Type guard: True if the pyproject.toml file exists."""
    return os.path.isfile(path)

from pip._internal.exceptions import InstallationError
from pip._internal.req.req_dependency_group import parse_dependency_groups

try:
    reqs = parse_dependency_groups([("pyproject.toml", "dev")])
except InstallationError as e:
    if "not found" in str(e):
        print("Create pyproject.toml or verify the working directory")
    else:
        raise

When it happens

Trigger: Running 'pip install --group dev' from a directory with no pyproject.toml, or specifying a custom pyproject.toml path that does not exist.

Common situations: Wrong working directory in CI or locally. Deleted or never-created pyproject.toml. Path typo. Running pip from a subdirectory of the project.

Related errors

• [dependency-groups] resolution failed for
• [dependency-groups] table was missing from
• [dependency-groups] data was invalid in
• [dependency-groups] table was malformed in
• Error parsing

AI-assisted analysis of pypa/pip@f399c37189 (2026-08-08). Data as JSON: /api/errors/d070071d2dfcf7f2. Report an issue: GitHub.

Appendix: source

Thrown at src/pip/_internal/req/req_dependency_group.py:82

            messages = [str(e) for e in eg.exceptions]
            raise InstallationError(
                f"[dependency-groups] data was invalid in {path}: {'; '.join(messages)}"
            ) from eg

    return resolvers


def _load_pyproject(path: str) -> dict[str, Any]:
    """
    This helper loads a pyproject.toml as TOML.

    It raises an InstallationError if the operation fails.
    """
    try:
        with open(path, "rb") as fp:
            return tomllib.load(fp)
    except FileNotFoundError:
        raise InstallationError(f"{path} not found. Cannot resolve '--group' option.")
    except tomllib.TOMLDecodeError as e:
        raise InstallationError(f"Error parsing {path}: {e}") from e
    except OSError as e:
        raise InstallationError(f"Error reading {path}: {e}") from e

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