laravel/framework · error · InvalidArgumentException

Number of groups must be at least 1.

Error message

Number of groups must be at least 1.

What it means

Thrown by Collection::split($numberOfGroups) when $numberOfGroups < 1. Splitting into zero or negative groups is meaningless; the method requires at least one target group. An empty collection is handled separately (returns empty instance) and does not trigger this.

Solutions

1. Clamp to 1: $collection->split(max(1, $numberOfGroups)).
2. Validate $numberOfGroups >= 1 before calling.
3. Compute group count defensively from a guaranteed-positive divisor.

Example fix

// before
$groups = $col->split($divisor); // throws if $divisor <= 0
// after
$groups = $col->split(max(1, (int) $divisor));

$groups = max(1, (int) $numberOfGroups);
$result = $collection->split($groups);

function isPositiveGroupCount(int $n): bool { return $n >= 1; }

try {
    $parts = $col->split($n);
} catch (\InvalidArgumentException $e) {
    $parts = $col->split(1);
}

When it happens

Trigger: Calling $collection->split(0) or ->split(-1), or passing a computed group count <= 0.

Common situations: Group count derived from a divisor that can be 0 (e.g. ceil(count / perGroup) when perGroup is huge); user-supplied group count not bounded.

Related errors

• Collection should only include
• Number of shifted items may not be less than zero.
• Size value must be at least 1.
• Step value must be at least 1.
• You requested items, but there are only items available.

AI-assisted analysis of laravel/framework@e0f6eb3518 (2026-08-11). Data as JSON: /api/errors/d96e0efa7f1975be. Report an issue: GitHub.

Appendix: source

Thrown at src/Illuminate/Collections/Collection.php:1385

     * @return static
     */
    public function slice($offset, $length = null)
    {
        return $this->newInstance(array_slice($this->items, $offset, $length, true));
    }

    /**
     * Split a collection into a certain number of groups.
     *
     * @param  int  $numberOfGroups
     * @return ($numberOfGroups is positive-int ? static<int, static> : never)
     *
     * @throws \InvalidArgumentException
     */
    public function split($numberOfGroups)
    {
        if ($numberOfGroups < 1) {
            throw new InvalidArgumentException('Number of groups must be at least 1.');
        }

        if ($this->isEmpty()) {
            return $this->newInstance();
        }

        $groups = $this->newInstance();

        $groupSize = floor($this->count() / $numberOfGroups);

        $remain = $this->count() % $numberOfGroups;

        $start = 0;

        for ($i = 0; $i < $numberOfGroups; $i++) {
            $size = $groupSize;

            if ($i < $remain) {

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