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 LazyCollection::split($numberOfGroups) when the count is less than 1. This is the lazy override that delegates via passthru() to the eager Collection::split, but it validates the argument first since the underlying source may not be materialized. Same precondition as the eager version.

Source

Thrown at src/Illuminate/Collections/LazyCollection.php:1316

        if ($offset < 0 || $length < 0) {
            return $this->passthru(__FUNCTION__, func_get_args());
        }

        $instance = $this->skip($offset);

        return is_null($length) ? $instance : $instance->take($length);
    }

    /**
     * {@inheritDoc}
     *
     * @throws \InvalidArgumentException
     */
    #[\Override]
    public function split($numberOfGroups)
    {
        if ($numberOfGroups < 1) {
            throw new InvalidArgumentException('Number of groups must be at least 1.');
        }

        return $this->passthru(__FUNCTION__, func_get_args());
    }

    /**
     * Get the first item in the collection, but only if exactly one item exists. Otherwise, throw an exception.
     *
     * @param  (callable(TValue, TKey): bool)|string|null  $key
     * @param  mixed  $operator
     * @param  mixed  $value
     * @return TValue
     *
     * @throws \Illuminate\Support\ItemNotFoundException
     * @throws \Illuminate\Support\MultipleItemsFoundException
     */
    public function sole($key = null, $operator = null, $value = null)
    {

View on GitHub (pinned to bd6b5437e6)

Solutions

1. Pass an integer >= 1 to split(); clamp with max(1, $n).
2. Default the group-count source to a positive value.
3. Guard the call site when the count may be 0 or negative.

Example fix

// before
$groups = $lazy->split($partitionCount);

// after
$groups = $lazy->split(max(1, (int) $partitionCount));

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

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

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

When it happens

Trigger: Calling $lazy->split(0) or $lazy->split(-2). Often with a dynamically computed group count from a query result size that can be 0.

Common situations: Splitting a lazy collection (e.g. from a cursor/generator) into N batches where N is derived from config or a count that resolves to 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.
• Generators should not be passed directly to LazyCollection.

AI-assisted analysis of laravel/framework@bd6b5437e6 (2026-08-06). Data as JSON: /data/errors/58155f4e398f4f6b.json. Report an issue: GitHub.