gohugoio/hugo · error

error correction level must be one of low, medium, quartile,

Error message

error correction level must be one of low, medium, quartile, or high

What it means

`images.QR` accepts an options map whose `level` sets the QR error-correction level. Hugo looks the value up in a fixed map (`low`, `medium`, `quartile`, `high` → qr.L/M/Q/H) and rejects anything else. The default is `medium` when the option is omitted.

Source

Thrown at tpl/images/images.go:155

	text, err := cast.ToStringE(args[0])
	if err != nil {
		return nil, err
	}

	if text == "" {
		return nil, errors.New("cannot encode an empty string")
	}

	if len(args) == 2 {
		err := mapstructure.WeakDecode(args[1], &opts)
		if err != nil {
			return nil, err
		}
	}

	level, ok := qrErrorCorrectionLevels[opts.Level]
	if !ok {
		return nil, errors.New("error correction level must be one of low, medium, quartile, or high")
	}

	if opts.Scale < 2 {
		return nil, errors.New("scale must be an integer greater than or equal to 2")
	}

	targetPath := path.Join(opts.TargetDir, fmt.Sprintf("qr_%s.png", hashing.HashStringHex(text, opts)))

	r, err := ns.createClient.FromOpts(
		create.Options{
			TargetPath:        targetPath,
			TargetPathHasHash: true,
			CreateContent: func() (func() (hugio.ReadSeekCloser, error), error) {
				code, err := qr.Encode(text, level)
				if err != nil {
					return nil, err
				}
				code.Scale = opts.Scale

View on GitHub ↗ (pinned to 8a468df065)

Solutions

1. Use one of the exact strings: `low`, `medium`, `quartile`, or `high` (lowercase).
2. Map other libraries' L/M/Q/H notation to the corresponding word before passing it.
3. Omit `level` entirely to get the default `medium`.

Example fix

<!-- before -->
{{ $qr := images.QR $text (dict "level" "H") }}
<!-- after -->
{{ $qr := images.QR $text (dict "level" "high") }}

{{ $level := .Params.qrLevel | default "medium" }}
{{ if not (in (slice "low" "medium" "quartile" "high") $level) }}
  {{ errorf "invalid qrLevel %q" $level }}
{{ end }}
{{ $qr := images.QR $text (dict "level" $level) }}

When it happens

Trigger: Calling `{{ images.QR $text (dict "level" "h") }}` or any `level` value outside the four exact lowercase names — e.g. `"L"`, `"High"`, `"25%"`, or a typo like `"quartlie"`.

Common situations: Using single-letter levels (L/M/Q/H) familiar from other QR libraries; capitalizing the level name; passing a percentage value from other tools' terminology.

Related errors

• scale must be an integer greater than or equal to 2
• cannot encode an empty string
• errKeyIsEmptyString
• invalid options type: %w
• %q is not a valid duration unit

AI-assisted analysis of gohugoio/hugo@8a468df065 (2026-07-31). Data as JSON: /data/errors/de65544ea03b0072.json. Report an issue: GitHub ↗.