docker/cli · error

unable to determine basename of plugin candidate %q

Error message

unable to determine basename of plugin candidate %q

What it means

Error "unable to determine basename of plugin candidate %q" thrown in docker/cli.

Source

Thrown at cli-plugins/manager/plugin.go:71

	Metadata() ([]byte, error)
}

// newPlugin determines if the given candidate is valid and returns a
// Plugin.  If the candidate fails one of the tests then `Plugin.Err`
// is set, and is always a `pluginError`, but the `Plugin` is still
// returned with no error. An error is only returned due to a
// non-recoverable error.
func newPlugin(c pluginCandidate, cmds []*cobra.Command) (Plugin, error) {
	path := c.Path()
	if path == "" {
		return Plugin{}, errors.New("plugin candidate path cannot be empty")
	}

	// The candidate listing process should have skipped anything
	// which would fail here, so there are all real errors.
	fullname := filepath.Base(path)
	if fullname == "." {
		return Plugin{}, fmt.Errorf("unable to determine basename of plugin candidate %q", path)
	}
	var err error
	if fullname, err = trimExeSuffix(fullname); err != nil {
		return Plugin{}, fmt.Errorf("plugin candidate %q: %w", path, err)
	}
	if !strings.HasPrefix(fullname, metadata.NamePrefix) {
		return Plugin{}, fmt.Errorf("plugin candidate %q: does not have %q prefix", path, metadata.NamePrefix)
	}

	p := Plugin{
		Name: strings.TrimPrefix(fullname, metadata.NamePrefix),
		Path: path,
	}

	// Now apply the candidate tests, so these update p.Err.
	if !isValidPluginName(p.Name) {
		p.Err = newPluginError("plugin candidate %q did not match %q", p.Name, pluginNameFormat)
		return p, nil

View on GitHub (pinned to e9452d6e78)

When it happens

Trigger: Thrown at cli-plugins/manager/plugin.go:71 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of docker/cli@e9452d6e78 (2026-08-01). Data as JSON: /data/errors/a94505d0835cae82.json. Report an issue: GitHub.