ldc-legaulois/app/Http/Requests/UpdateMiniAcfRequest.php

<?php

namespace App\Http\Requests;

use Illuminate\Contracts\Validation\Factory as ValidationFactory;

class UpdateMiniAcfRequest extends StoreMiniAcfRequest
{
    protected $isStore = false;

    /**
     * The model var name
     * used as route parameter name
     *
     * This is used to populate generatedRules
     *
     * @var array
     */
    protected $modelVarName;

    /**
     * Overload createDefaultValidator
     * to generate rules and merge data
     * like booleans before validator is created
     * as it copies data from the request.
     *
     * The reason : using $this->merge in rules method
     * will not be taken into account
     *
     * @param ValidationFactory $factory
     * @return void
     */
    protected function createDefaultValidator(ValidationFactory $factory)
    {
        $this->generatedRules = $this->genRules($this->{$this->modelVarName}->content);
        return parent::createDefaultValidator($factory);
    }
}