What causes "Size value must be at least 1." in laravel/framework?

Ensure size >= 1: ->sliding(max(1, $size), max(1, $step)).

laravel/framework · error · InvalidArgumentException

Size value must be at least 1.

Error message

Size value must be at least 1.

What it means

Thrown by LazyCollection::sliding($size, $step) when $size < 1. sliding builds overlapping 'window' chunks of $size elements advancing by $step; a window size below 1 cannot produce a valid chunk and is rejected with an InvalidArgumentException. The PHPDoc marks both params as positive-int.

Solutions

Ensure size >= 1: ->sliding(max(1, $size), max(1, $step)).
Validate both size and step before calling.
Provide a sensible default (size=2) when sourced from user input.

Example fix

// before
$windows = $collection->sliding($windowSize, $step);
// after
$windowSize = max(1, $windowSize);
$step = max(1, $step);
$windows = $collection->sliding($windowSize, $step);

Defensive patterns

Strategy: validation

Validate before calling

if ($size < 1 || $step < 1) {
    throw new \InvalidArgumentException('sliding size and step must be >= 1');
}
return $collection->sliding($size, $step);

Type guard

$size = (is_int($size) && $size >= 1) ? $size : 2;
$step = (is_int($step) && $step >= 1) ? $step : 1;

Try / catch

try {
    return $collection->sliding($size, $step);
} catch (\InvalidArgumentException $e) {
    return $collection->sliding(2, 1);
}

Prevention

Clamp both size and step: sliding(max(1,$size), max(1,$step)).
Validate window configs at the request boundary.
Default window size to 2 and step to 1 in config.

When it happens

Trigger: ->sliding(0), ->sliding(-1); size derived from a length/width setting that can be zero; passing a configurable window size from a request.

Common situations: Time-series windowing where window size is configurable; pagination window math that yields 0 for small datasets; defaults left at 0 in config.

Related errors

AI-assisted analysis of laravel/framework@e0f6eb3518 (2026-08-11). Data as JSON: /api/errors/366743ac97778e9a. Report an issue: GitHub.

Appendix: source

Thrown at src/Illuminate/Collections/LazyCollection.php:1198

    #[\Override]
    public function shuffle()
    {
        return $this->passthru(__FUNCTION__, []);
    }

    /**
     * Create chunks representing a "sliding window" view of the items in the collection.
     *
     * @param  positive-int  $size
     * @param  positive-int  $step
     * @return static<int, static>
     *
     * @throws \InvalidArgumentException
     */
    public function sliding($size = 2, $step = 1)
    {
        if ($size < 1) {
            throw new InvalidArgumentException('Size value must be at least 1.');
        } elseif ($step < 1) {
            throw new InvalidArgumentException('Step value must be at least 1.');
        }

        return new static(function () use ($size, $step) {
            $iterator = $this->getIterator();

            $chunk = [];

            while ($iterator->valid()) {
                $chunk[$iterator->key()] = $iterator->current();

                if (count($chunk) == $size) {
                    yield (new static($chunk))->tap(function () use (&$chunk, $step) {
                        $chunk = array_slice($chunk, $step, null, true);
                    });

                    // If the $step between chunks is bigger than each chunk's $size

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