What causes "no color stops in gradient" in d2lang/d2?

Add at least one color stop after the direction, e.g. 'linear-gradient(45deg, #fff, #000)'

no color stops in gradient

Error message

no color stops in gradient

What it means

ParseGradient validates CSS gradient parameter lists. After a direction token (e.g. '45deg' or 'to right' for linear, 'circle'/'ellipse' for radial) is consumed, at least one color stop must remain; if the direction token is the only parameter, the gradient would have nothing to render, so it returns this error.

Solutions

Add at least one color stop after the direction, e.g. 'linear-gradient(45deg, #fff, #000)'
Remove the trailing direction-only parameter list or the whole gradient value if a plain color was intended
Validate the gradient string with ValidColor before use and surface a clearer message to the user

Example fix

// before
ParseGradient("linear-gradient(45deg)")
// after
ParseGradient("linear-gradient(45deg, blue, red)")

Defensive patterns

Strategy: validation

Validate before calling

params := strings.Split(inner, ",")
first := strings.TrimSpace(params[0])
if (strings.HasSuffix(first, "deg") || strings.HasPrefix(first, "to ")) && len(params) < 2 {
    return errors.New("gradient needs at least one color stop after direction")
}

Try / catch

g, err := ParseGradient(s)
if err != nil {
    // fallback: treat s as a plain color or surface the validation message
}

Prevention

Always include at least one color stop after a direction token
Validate gradient strings with ValidColor before persisting them
Build gradients programmatically with strings.Join(stops, ", ") to avoid truncation

When it happens

Trigger: Calling ParseGradient (indirectly via ValidColor) with a gradient string like 'linear-gradient(45deg)' or 'radial-gradient(circle)' where the parameter list contains only a direction and zero color stops.

Common situations: Hand-written CSS color values with a truncated gradient, templates interpolating an empty color list after a direction, or config files where the stops were accidentally dropped.

Related errors

AI-assisted analysis of d2lang/d2@0d69dca6f5 (2026-08-31). Data as JSON: /api/errors/2a58d2ce4944447b. Report an issue: GitHub.

Appendix: source

Thrown at lib/color/gradient.go:54

	params := matches[2]

	gradient := Gradient{
		Type: strings.TrimSuffix(gradientType, "-gradient"),
	}

	paramList := splitParams(params)

	if len(paramList) == 0 {
		return Gradient{}, errors.New("no parameters in gradient")
	}

	firstParam := strings.TrimSpace(paramList[0])

	if gradient.Type == "linear" && (strings.HasSuffix(firstParam, "deg") || strings.HasPrefix(firstParam, "to ")) {
		gradient.Direction = firstParam
		colorStops := paramList[1:]
		if len(colorStops) == 0 {
			return Gradient{}, errors.New("no color stops in gradient")
		}
		gradient.ColorStops = parseColorStops(colorStops)
	} else if gradient.Type == "radial" && (firstParam == "circle" || firstParam == "ellipse") {
		gradient.Direction = firstParam
		colorStops := paramList[1:]
		if len(colorStops) == 0 {
			return Gradient{}, errors.New("no color stops in gradient")
		}
		gradient.ColorStops = parseColorStops(colorStops)
	} else {
		gradient.ColorStops = parseColorStops(paramList)
	}
	gradient.ID = UniqueGradientID(cssGradient)

	return gradient, nil
}

func splitParams(params string) []string {

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