pypa/pip · error · CommandError

Cannot use '--only-dependencies' in combination with {confli

Error message

Cannot use '--only-dependencies' in combination with {conflict_message}. If this is unexpected, please refer to the user guide:

    https://pip.pypa.io/en/stable/user_guide/#installing-only-dependencies

What it means

Raised by check_only_deps_option_does_not_conflict() in cmdoptions.py:91 when --only-dependencies is combined with one or more incompatible options: --no-deps, --use-deprecated legacy-resolver, --requirement (-r), --requirements-from-script, or --group. The error message lists all conflicting options and links to the user guide for the --only-dependencies feature.

Source

Thrown at src/pip/_internal/cli/cmdoptions.py:91

    """
    if not options.only_dependencies:
        return
    conflicts = []
    if options.ignore_dependencies:
        conflicts.append("'--no-deps'")
    if "legacy-resolver" in options.deprecated_features_enabled:
        conflicts.append("'--use-deprecated legacy-resolver'")
    if options.requirements:
        conflicts.append("'--requirement'")
    if options.requirements_from_scripts:
        conflicts.append("'--requirements-from-script'")
    if options.dependency_groups:
        conflicts.append("'--group'")
    if conflicts:
        if len(conflicts) > 1:
            conflicts[-1] = "or " + conflicts[-1]
        conflict_message = ", ".join(conflicts)
        raise CommandError(
            f"Cannot use '--only-dependencies' in combination with {conflict_message}. "
            "If this is unexpected, please refer to the user guide:\n"
            "\n"
            "    https://pip.pypa.io/en/stable/user_guide/#installing-only-dependencies"
        )


def check_dist_restriction(options: Values, check_target: bool = False) -> None:
    """Function for determining if custom platform options are allowed.

    :param options: The OptionParser options.
    :param check_target: Whether or not to check if --target is being used.
    """
    dist_restriction_set = any(
        [
            options.python_version,
            options.platforms,
            options.abis,

View on GitHub (pinned to d7d0d0a394)

Solutions

1. Remove the conflicting option identified in the error message.
2. If you want deps from a requirements file without --only-deps, just use `pip install -r requirements.txt`.
3. If you want a group's dependencies, use `pip install --group dev` without --only-deps.
4. Switch from the legacy resolver to the default (resolvelib) resolver.

Example fix

# before
pip install --only-deps --no-deps mypackage

# after
pip install --only-deps mypackage
# (remove --no-deps; --only-deps already handles dependency-only install)

def validate_only_deps_options(options):
    """Validate --only-deps doesn't conflict with incompatible options."""
    if not options.get('only_dependencies'):
        return True
    conflicts = ['no-deps', 'legacy-resolver', 'requirement', 'requirements-from-script', 'group']
    for c in conflicts:
        if options.get(c):
            return False
    return True

from pip._internal.exceptions import CommandError
try:
    # pip install invocation
except CommandError as e:
    if "'--only-dependencies'" in str(e):
        # remove conflicting option and retry

When it happens

Trigger: Calling `pip install --only-deps --no-deps <pkg>`, `pip install --only-deps -r requirements.txt`, `pip install --only-deps --group dev`, `pip install --only-deps --requirements-from-script script.py`, or `pip install --only-deps --use-deprecated legacy-resolver <pkg>`.

Common situations: Trying to install only dependencies of a requirements file but also passing --no-deps (logical contradiction). Mixing --group with --only-deps thinking it will install the group's deps. Using the legacy resolver with --only-deps (unsupported combination). Misunderstanding what --only-deps does (it installs the transitive dependencies of named requirements, excluding the requirements themselves).

Related errors

• When restricting platform and interpreter constraints using
• Can not use any platform or abi specific options unless inst
• Platform and interpreter constraints using --python-version,
• --build-constraint cannot be used with --no-build-isolation.
• --pre cannot be used with --all-releases or --only-final.

AI-assisted analysis of pypa/pip@d7d0d0a394 (2026-08-04). Data as JSON: /data/errors/eebe45060caf760f.json. Report an issue: GitHub.