pypa/pip · error · CommandError

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

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 as CommandError by check_only_deps_option_does_not_conflict (cmdoptions.py:91) when --only-dependencies is combined with mutually exclusive options. The function (lines 68-96) collects conflicts from --no-deps, --use-deprecated legacy-resolver, -r/--requirement, --requirements-from-script, and --group, joining them into a human-readable message and pointing at the user guide. --only-dependencies installs only the transitive dependencies of the requested packages, which is semantically incompatible with options that change the dependency set or supply the requirements directly.

Solutions

1. Drop the conflicting option. To install only dependencies from a requirements file, copy/extract the dependency lines instead of using -r with --only-dependencies.
2. If you want no dependencies at all, use --no-deps by itself (not --only-dependencies).
3. If you want the package plus its deps, omit --only-dependencies entirely.

Example fix

# before
pip install --only-dependencies --no-deps mypkg
# after (pick one intent)
pip install --only-dependencies mypkg
# or
pip install --no-deps mypkg

# Validate option set before constructing the pip command.
def safe_only_deps(opts):
    conflicts = []
    if opts.get("no_deps"): conflicts.append("--no-deps")
    if opts.get("requirement"): conflicts.append("-r/--requirement")
    if opts.get("requirements_from_script"): conflicts.append("--requirements-from-script")
    if opts.get("group"): conflicts.append("--group")
    if opts.get("use_deprecated_legacy_resolver"): conflicts.append("legacy-resolver")
    if opts.get("only_dependencies") and conflicts:
        raise ValueError(f"--only-dependencies conflicts with {conflicts}")
    return True

When it happens

Trigger: Running `pip install --only-dependencies --no-deps <pkg>`, `pip install --only-dependencies -r requirements.txt`, `pip install --only-dependencies --group dev`, or combining --only-dependencies with the legacy resolver.

Common situations: Adopting the new --only-dependencies flag in a Makefile/script that already passes -r or --no-deps; copy-pasting option combinations from a working install command without realizing the new flag conflicts; trying to install just dependencies of a locked set while also disabling deps.

Related errors

• Cannot combine '--path' with '--user' or '--local'
• --pre cannot be used with --all-releases or --only-final.
• --require-hashes and --no-require-hashes are mutually…
• --build-constraint cannot be used with --no-build-isolation.
• Can not use any platform or abi specific options unless…

AI-assisted analysis of pypa/pip@f399c37189 (2026-08-08). Data as JSON: /api/errors/eebe45060caf760f. Report an issue: GitHub.

Appendix: 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,

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