glanceapp/glance · error

invalid HSL color format: %s

Error message

invalid HSL color format: %s

What it means

Returned by hslColorField.UnmarshalYAML when a YAML value destined for an HSL color field (e.g. theme colors like primary-color) does not match the expected 'H S% L%' pattern. The regex hslColorFieldPattern expects 3 capture groups (hue, saturation, lightness); a FindStringSubmatch result of any length other than 4 (full match + 3 groups) triggers this error with the offending value echoed back.

Source

Thrown at internal/glance/config-fields.go:59

		return true
	}
	if c1 == nil || c2 == nil {
		return false
	}
	return c1.H == c2.H && c1.S == c2.S && c1.L == c2.L
}

func (c *hslColorField) UnmarshalYAML(node *yaml.Node) error {
	var value string

	if err := node.Decode(&value); err != nil {
		return err
	}

	matches := hslColorFieldPattern.FindStringSubmatch(value)

	if len(matches) != 4 {
		return fmt.Errorf("invalid HSL color format: %s", value)
	}

	hue, err := strconv.ParseFloat(matches[1], 64)
	if err != nil {
		return err
	}

	if hue > hslHueMax {
		return fmt.Errorf("HSL hue must be between 0 and %d", hslHueMax)
	}

	saturation, err := strconv.ParseFloat(matches[2], 64)
	if err != nil {
		return err
	}

	if saturation > hslSaturationMax {
		return fmt.Errorf("HSL saturation must be between 0 and %d", hslSaturationMax)

View on GitHub (pinned to 91324e8de7)

Solutions

1. Use the exact HSL form without parentheses: `primary-color: 200 50% 40%` (hue 0-360, saturation and lightness with %).
2. Convert hex colors to HSL before putting them in theme config (Glance theme color fields take HSL, not hex).
3. Validate with `glance config:validate` to locate the offending key.

Example fix

# glance.yml (before)
theme:
  primary-color: #3442bb

# after
theme:
  primary-color: 232 55% 47%

python3 - <<'EOF'
import re,sys
pat=re.compile(r'^\d+(\.\d+)? \d+(\.\d+)?% \d+(\.\d+)?%$')
for line in open('glance.yml'):
    if re.search(r'-(\s*\w+-?color):',line):
        key,val=line.split(':',1)
        if val.strip() and not pat.match(val.strip()):
            sys.exit(f'bad HSL: {line.strip()}')
print('ok')
EOF

When it happens

Trigger: Writing primary-color: #ff0000 (hex), primary-color: red, primary-color: 200 50 (missing lightness), or hsl(200, 50%, 40%) with wrong punctuation/spacing; any string the HSL regex cannot fully match.

Common situations: Mixing up hex and HSL formats between theme keys; copying hex colors from a design tool; missing the % sign on saturation/lightness; extra spaces or commas the pattern doesn't allow.

Related errors

• HSL hue must be between 0 and %d
• HSL saturation must be between 0 and %d
• HSL lightness must be between 0 and %d
• URL is required
• nested groups are not supported

AI-assisted analysis of glanceapp/glance@91324e8de7 (2026-08-15). Data as JSON: /api/errors/3ded4eea7ee544d0. Report an issue: GitHub.