symfony/var-dumper · error · InvalidArgumentException

Theme " " does not exist in class " ".

Error message

Theme "%s" does not exist in class "%s".

What it means

HtmlDumper::setTheme() validates the theme name against static::$themes (which defines 'default' and 'dark'). An unknown name throws InvalidArgumentException instead of silently keeping the current styles.

Solutions

1. Use a built-in theme name: 'default' or 'dark'
2. Check available themes in HtmlDumper::$themes for your installed version
3. For custom themes, subclass HtmlDumper, add an entry to static::$themes, then call setTheme on the subclass

Example fix

// before
$dumper->setTheme('light');
// after
$dumper->setTheme('dark');

$theme = $options['theme'] ?? 'default';
if (!isset(\Symfony\Component\VarDumper\Dumper\HtmlDumper::$themes[$theme])) {
    throw new \InvalidArgumentException(sprintf('Unknown theme "%s"; available: %s', $theme, implode(', ', array_keys(\Symfony\Component\VarDumper\Dumper\HtmlDumper::$themes))));
}

function themeExists(string $theme, string $class = \Symfony\Component\VarDumper\Dumper\HtmlDumper::class): bool {
    return isset($class::$themes[$theme]);
}

try {
    $dumper->setTheme($theme);
} catch (\InvalidArgumentException $e) {
    $logger->warning($e->getMessage());
    $dumper->setTheme('default');
}

When it happens

Trigger: Calling `(new HtmlDumper())->setTheme('light')` or setTheme with any name not present in HtmlDumper::$themes; configuring a profiler/dump output with a mistyped theme option.

Common situations: Typos like 'dark-theme' or 'light'; assuming other themes exist; custom themes registered in a subclass but setTheme called on the base class.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Unsupported format " ".

AI-assisted analysis of symfony/var-dumper@e9d9cf5dcd (2026-09-14). Data as JSON: /api/errors/a913c192201656e8. Report an issue: GitHub.

Appendix: source

Thrown at Dumper/HtmlDumper.php:98

    public function __construct($output = null, ?string $charset = null, int $flags = 0)
    {
        AbstractDumper::__construct($output, $charset, $flags);
        $this->dumpId = 'sf-dump-'.mt_rand();
        $this->displayOptions['fileLinkFormat'] = \ini_get('xdebug.file_link_format') ?: get_cfg_var('xdebug.file_link_format');
        $this->styles = static::$themes['dark'] ?? self::$themes['dark'];
    }

    public function setStyles(array $styles): void
    {
        $this->headerIsDumped = false;
        $this->styles = $styles + $this->styles;
    }

    public function setTheme(string $themeName): void
    {
        if (!isset(static::$themes[$themeName])) {
            throw new \InvalidArgumentException(\sprintf('Theme "%s" does not exist in class "%s".', $themeName, static::class));
        }

        $this->setStyles(static::$themes[$themeName]);
    }

    /**
     * Configures display options.
     *
     * @param array $displayOptions A map of display options to customize the behavior
     */
    public function setDisplayOptions(array $displayOptions): void
    {
        $this->headerIsDumped = false;
        $this->displayOptions = $displayOptions + $this->displayOptions;
    }

    /**
     * Sets an HTML header that will be dumped once in the output stream.

View on GitHub (pinned to e9d9cf5dcd)