kovidgoyal/kitty · error

not a valid color name: %#v

Error message

not a valid color name: %#v

What it means

Raised by ParseColor when the input (trimmed, lowercased) is neither a key in the ColorNames map nor long enough (≥4 chars) to possibly be a structured color. Short strings that aren't known color names can never match any of the structured parsers, so they are rejected immediately.

Source

Thrown at tools/utils/style/wrapper.go:208

	if strings.HasPrefix(color, "#") {
		// For hex colors, only strip comments after whitespace
		parts := strings.Fields(color)
		if len(parts) > 0 {
			color = parts[0] // Keep only the hex color part
		}
	} else {
		// For non-hex colors, strip everything after #
		if idx := strings.Index(color, "#"); idx >= 0 {
			color = strings.TrimSpace(color[:idx])
		}
	}

	raw := strings.TrimSpace(strings.ToLower(color))
	if val, ok := ColorNames[raw]; ok {
		return val, nil
	}
	if len(raw) < 4 {
		return RGBA{}, fmt.Errorf("not a valid color name: %#v", color)
	}
	var parser func(string) (RGBA, error)
	switch raw[0] {
	case '#':
		parser = parse_sharp
		raw = raw[1:]
	case 'o':
		if strings.HasPrefix(raw, "oklch(") {
			parser, raw = parseOklch, raw[6:]
		}
	case 'l':
		if strings.HasPrefix(raw, "lab(") {
			parser, raw = parseLab, raw[4:]
		}
	case 'r':
		if len(raw) > 4 && strings.HasPrefix(raw, "rgb") {
			raw = raw[3:]
			switch raw[0] {

View on GitHub (pinned to 6d5d0c4406)

Solutions

1. Check for empty/unset color variables before calling ParseColor (e.g. missing env var produced "").
2. Use a known color name from ColorNames (red, green, ...) for short values.
3. For structured formats, ensure the string is at least 4 characters (e.g. "#fff" + prefix requirements).
4. Trim input and log the offending value when the error occurs.

Example fix

// before
col, err := style.ParseColor(os.Getenv("ACCENT")) // ACCENT unset → ""

// after
v := strings.TrimSpace(os.Getenv("ACCENT"))
if v == "" { v = "red" }
col, err := style.ParseColor(v)

func nonEmptyColorName(s string) bool {
	return len(strings.TrimSpace(s)) > 0
}

if _, err := style.ParseColor(v); err != nil {
	return fmt.Errorf("invalid color %q: %w", v, err)
}

When it happens

Trigger: ParseColor("abc") (3 chars, not a known name), ParseColor(""), ParseColor(" # ") after trimming, or a 1–3 character typo like "rd" instead of "red".

Common situations: Typos in named colors, empty values from unset config/env variables, or strings that were mangled by earlier processing (e.g. comment-stripping removing most of the input).

Related errors

• length not a multiple of 3
• not a valid color name: %#v %w
• Invalid color name: {raw!r}
• invalid rgb numbers
• No kitten named {original_kitten_name}

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/e662fe3003a74fac. Report an issue: GitHub.