%s is invalid. Name may only contain lowercase letters, numb

Error message

%s is invalid. Name may only contain lowercase letters, numbers, '_', and '-'

What it means

asdf restricts plugin names to lowercase letters, digits, '_' and '-' (regexp ^[[:lower:][:digit:]_-]+$). validatePluginName runs at the top of Add and Remove; any name with uppercase letters, spaces, dots or other characters is rejected with this message naming the offending name. This keeps plugin names safe as directory names and hook suffixes.

Source

Thrown at internal/plugins/plugins.go:504

	if errors.Is(err, os.ErrNotExist) {
		return false, nil
	}

	if err != nil {
		return false, err
	}

	return fileInfo.IsDir(), nil
}

func validatePluginName(name string) error {
	match, err := regexp.MatchString("^[[:lower:][:digit:]_-]+$", name)
	if err != nil {
		return err
	}

	if !match {
		return fmt.Errorf(invalidPluginNameMsg, name)
	}

	return nil
}

View on GitHub (pinned to 074a1722ca)

Solutions

Rename to lowercase, using '-' or '_' as separators (e.g. 'my-plugin')
Check for stray whitespace or hidden characters in the name argument
Validate/normalize the name in your own code before calling Add/Remove

Example fix

// before
plugins.Add(conf, "NodeJS", url, "", os.Stdout)
// after
plugins.Add(conf, "nodejs", url, "", os.Stdout)

Defensive patterns

Strategy: validation

Validate before calling

var pluginNameRe = regexp.MustCompile(`^[[:lower:][:digit:]_-]+$`)
if !pluginNameRe.MatchString(name) {
    return fmt.Errorf("invalid plugin name: %q", name)
}

Type guard

func validPluginName(name string) bool {
    return regexp.MustCompile(`^[[:lower:][:digit:]_-]+$`).MatchString(name)
}

Prevention

Normalize names to lowercase with '-'/'_' separators before calling Add/Remove
Trim whitespace from user-supplied plugin names

When it happens

Trigger: plugins.Add or plugins.Remove (or CLI add/remove) with names containing uppercase letters, spaces, dots (e.g. 'My.Plugin', 'node js'), or other non-matching characters.

Common situations: Copy-pasting a plugin repo name like 'asdf-nodejs' with different casing, using the plugin's display name with spaces, or interpolating a variable that is empty or contains slashes.

Related errors

AI-assisted analysis of asdf-vm/asdf@074a1722ca (2026-08-30). Data as JSON: /api/errors/426403db2c92cc08. Report an issue: GitHub.