Nesting Rule::foreach with closure

You a re using the Rule incorrectly - it should be applied on one nested key, not on the nested array

'items.*.id' => Rule::forEach(function ($attribute, $value) {
	return [
        // rules for `id`
    ];
})

https://laravel.com/docs/9.x/validation#accessing-nested-array-data

thank you @tykus. But the short docs doesn't explicitly state that the key should not be nested array.

But it seems it doesn't support my logic so I have opted to following approach.

 return [
    'items' => 'array|required|min:1',
    'items.*' => Rule::forEach(function () {
        return [
            function ($attr, $value, $fail) {
                
                $subValidator = Validator::make($value, [
                    'id' => 'bail|required|exists:App\Models\Product,id',
                    'qty' => 'bail|required|integer|numeric|min:0'
                ], ['id.exists' => ':attribute does not exists']);

                if ($subValidator->fails()) {
                    return $fail($subValidator->errors()->first());
                }
                //rest of validation logic
                }
              ]
             })
  ]

you should use "Rule::forEach" on 'items' and not on 'items.*', like this, then it will work

return [
    'items' => ['array','required', 'min:1',Rule::forEach(function () {
        return [
            function ($attribute, $value, $fail) {
                $model = Product::findOrFail($value['id']);
                if ($model->balance < $value['qty']) {
                    return $fail($attribute . '.qty exceeds existing balance');
                }
                return true;
            },
            'id' => 'bail|required|exists:App\Models\Product,id',
            'qty' => 'bail|required|integer|numeric|min:0',
        ];
    })],
];