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() when the requested number of groups is less than 1. split() divides the collection into a fixed count of roughly-equal groups, so a non-positive group count has no meaningful result. The guard exists at the top of the method before any slicing math runs. InvalidArgumentException is thrown immediately.

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) {

View on GitHub (pinned to bd6b5437e6)

Solutions

1. Pass an integer >= 1 to split(); clamp the dynamic value with max(1, $count) before calling.
2. Validate the source variable is positive before the call (e.g. abort_if($groups < 1)).
3. If the count is genuinely unknown/0, guard the call site: $groups > 0 ? $c->split($groups) : $c->chunk(1).

Example fix

// before
$parts = $collection->split($userRequestedGroups);

// after
$parts = $collection->split(max(1, (int) $userRequestedGroups));

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

function isValidGroupCount($n): bool { return is_int($n) && $n >= 1; }

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

When it happens

Trigger: Calling $collection->split(0) or $collection->split(-3). Also when a computed/groupCount variable evaluates to 0 or negative, e.g. split(count($arr) - count($arr)) or split($request->input('groups')) with an unvalidated negative input.

Common situations: Dynamic group counts derived from user input, request params, or database values that can be 0 when a list/section is empty. Refactoring from chunk() (which takes size) to split() (which takes count) and accidentally passing 0.

Related errors

• Step value cannot be zero.
• Step value must be at least 1.
• Size value must be at least 1.
• Number of groups must be at least 1.
• You requested {$requested} items, but there are only {$count

AI-assisted analysis of laravel/framework@bd6b5437e6 (2026-08-06). Data as JSON: /data/errors/d96e0efa7f1975be.json. Report an issue: GitHub.