Validation - nested array rules

[azzumed]

💡 Idea: Nested Array Validation Rules for Cleaner Syntax

Hi everyone!

I'd like to propose a small but pretty improvement to Laravel's Validator: supporting nested array syntax for validation rules.

---

📌 Problem

Currently, when validating nested arrays - especially with wildcards (*) - the rule definitions can become repetitive. For example:

public function rules() {
    return [
        'album_id' => ['required', 'integer', 'exists:albums,id'],
        'photos.*.name' => ['required', 'string'],
        'photos.*.description' => ['nullable', 'string'],
        'photos.*.file' => ['required', 'file'],
    ];
}

As photos properties grow in complexity, managing rules this way gets tedious and error-prone.

---

✅ Suggested Improvement

I'd like to suggest allowing a more expressive, structured syntax using nested arrays:

public function rules() {
    return [
        'album_id' => ['required', 'integer', 'exists:albums,id'],
        'photos.*' => [
            'name' => ['required', 'string'],
            'description' => ['nullable', 'string'],
            'file' => ['required', 'file'],
        ],
    ];
}

Laravel would automatically flatten this into traditional rule keys like photos.*.name, photos.*.description, etc.

---

🔧 Possible Implementation

Flattening these nested rules could be done using a helper similar to Arr::dot, but with special handling to ignore list-style arrays and preserve wildcard logic:

function array_dot_except_list($array, $prepend = ''): array
{
    $results = [];

    $flatten = function ($data, $prefix) use (&$results, &$flatten): void {
        foreach ($data as $key => $value) {
            $newKey = $prefix.$key;

            if (is_array($value) && ! empty($value) && !array_is_list($value)) {
                $flatten($value, $newKey.'.');
            } else {
                $results[$newKey] = $value;
            }
        }
    };

    $flatten($array, $prepend);

    return $results;
}

This would allow Laravel to pre-process rules before validation, making the developer experience much smoother for large arrays.

[azzumed]

What do you think about implementation: should i add new method to Arr:: helper, or add third argument to Arr::dot, like $exceptList = false ?

[shaedrich]

Tried that with #55491, Taylor didn't like it 🤷🏻‍♂️