filp/whoops · error · InvalidArgumentException

Expecting callback argument to be callable

Error message

Expecting callback argument to be callable

What it means

Error "Expecting callback argument to be callable" thrown in filp/whoops.

Source

Thrown at src/Whoops/Handler/PrettyPageHandler.php:385

    /**
     * Lazily adds an entry to the list of tables displayed in the table.
     *
     * The supplied callback argument will be called when the error is
     * rendered, it should produce a simple associative array. Any nested
     * arrays will be flattened with `print_r`.
     *
     * @param string   $label
     * @param callable $callback Callable returning an associative array
     *
     * @throws InvalidArgumentException If $callback is not callable
     *
     * @return static
     */
    public function addDataTableCallback($label, /* callable */ $callback)
    {
        if (!is_callable($callback)) {
            throw new InvalidArgumentException('Expecting callback argument to be callable');
        }

        $this->extraTables[$label] = function (?\Whoops\Inspector\InspectorInterface $inspector = null) use ($callback) {
            try {
                $result = call_user_func($callback, $inspector);

                // Only return the result if it can be iterated over by foreach().
                return is_array($result) || $result instanceof \Traversable ? $result : [];
            } catch (\Exception $e) {
                // Don't allow failure to break the rendering of the original exception.
                return [];
            }
        };

        return $this;
    }

    /**

View on GitHub (pinned to fa1bc9c95a)

When it happens

Trigger: Thrown at src/Whoops/Handler/PrettyPageHandler.php:385 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of filp/whoops@fa1bc9c95a (2026-08-21). Data as JSON: /api/errors/718f0254293d033d. Report an issue: GitHub.