Laravel 5.6. Fail, if 2 specific fields are present in the request

Question

I have 2 fields in the request. field1 and field2.

What rules should I define in the FormRequest to fail validation, if both are present?

Answer 1

AFAIK there is no validation rule for this, you could write one, or if it's one-off, you could write a closure:

    'field1' => function ($attribute, $value, $fail) {
        if ($value && $this->input('field2')) {
            return $fail($attribute.' can only be filled when field2 is empty.');
        }
    },

https://laravel.com/docs/5.6/validation#using-closures

Note: Outside of a FormRequest class, you would need to use something other than $this->input()