helm/helm · error

not a directory

Error message

not a directory

What it means

setIndex (pkg/strvals/parser.go:308) rejects negative indexes with this message. For normal --set input this guard is shadowed by the earlier check in parser.listItem (parser.go:335), so seeing it means setIndex was reached with i < 0 directly — typically the same malformed input ('a[-1]=v') but observed from the lower-level call path, or a program calling setIndex-shaped flows via the public Parse APIs on unusual input.

Source

Thrown at internal/chart/v3/lint/rules/template.go:218

	return scanner.Err()
}

// Validation functions
func templatesDirExists(templatesPath string) error {
	_, err := os.Stat(templatesPath)
	if errors.Is(err, os.ErrNotExist) {
		return errors.New("directory does not exist")
	}
	return nil
}

func validateTemplatesDir(templatesPath string) error {
	fi, err := os.Stat(templatesPath)
	if err != nil {
		return err
	}
	if !fi.IsDir() {
		return errors.New("not a directory")
	}
	return nil
}

func validateAllowedExtension(fileName string) error {
	ext := filepath.Ext(fileName)
	validExtensions := []string{".yaml", ".yml", ".tpl", ".txt"}

	if slices.Contains(validExtensions, ext) {
		return nil
	}

	return fmt.Errorf("file extension '%s' not valid. Valid extensions are .yaml, .yml, .tpl, or .txt", ext)
}

func validateYamlContent(err error) error {
	if err != nil {
		return fmt.Errorf("unable to parse YAML: %w", err)

View on GitHub (pinned to 2a29f1770b)

Solutions

1. Use a non-negative 0-based index
2. Compute the correct index client-side instead of relying on negative semantics
3. Validate bracket contents are ^\[\d+\]$ before calling Parse

Example fix

// before
strvals.Parse("items[-1]=x")
// after
strvals.Parse("items[0]=x")

var negIdx = regexp.MustCompile(`\[-\d+\]`)
func hasNegativeIndex(setLine string) bool { return negIdx.MatchString(setLine) }

if err := strvals.Parse(s); err != nil {
    if strings.Contains(err.Error(), "negative") && strings.Contains(err.Error(), "index not allowed") { /* fix index */ }
}

When it happens

Trigger: strvals.Parse("a[-1]=v") normally surfaces the listItem variant; this variant appears when the negative index reaches setIndex itself, e.g. through nested paths or direct library use patterns.

Common situations: Same as negative-index errors generally: negative indexing expectations, bad interpolation producing -1, off-by-one loop counters.

Related errors

• file does not exist
• each maintainer requires a name
• icon is recommended
• not a directory
• apiVersion is not in 'apiextensions.k8s.io'

AI-assisted analysis of helm/helm@2a29f1770b (2026-08-15). Data as JSON: /api/errors/25157056f8e73925. Report an issue: GitHub.