Magento 2.2 - custom product sorting issue

Question

I have override toolbar.php for custom sorting attribute.

<?php
    namespace Vendor\Module\Block\Product\ProductList;
    class Toolbar extends \Magento\Catalog\Block\Product\ProductList\Toolbar
    {
        protected $_template = 'Magento_Catalog::product/list/toolbar.phtml'; 

        public function setCollection($collection)
        {
            $this->_collection = $collection;

            $this->_collection->setCurPage($this->getCurrentPage());

            $limit = (int) $this->getLimit();
            if ($limit) {
                $this->_collection->setPageSize($limit);
            }
            if ($this->getCurrentOrder()) {
                if ($this->getCurrentOrder() == 'stock') {
                    $this->_collection->getSelect()
                        ->joinLeft(
                                'cataloginventory_stock_item AS csi',
                                'e.entity_id = csi.product_id',
                                'csi.qty AS quantity'
                        )
                    ->group('e.entity_id')
                    ->order('quantity ' .$this->getCurrentDirectionReverse());
                } elseif ($this->getCurrentOrder() == 'created_at') {
                    $this->_collection
                       ->setOrder(
                            $this->getCurrentOrder(),
                            $this->getCurrentDirectionReverse()
                    );
               } else {
                    $this->_collection
                         ->setOrder(
                               $this->getCurrentOrder(),
                               $this->getCurrentDirection()
                         );
                }
            }
            return $this->_collection;
        }
    }

Select created_at attribute in frontend, it display good result.

But after select stock attribute, it display below error.

[2017-11-17 04:28:36] main.CRITICAL: You cannot define a correlation name 'csi' more than once [] []

I noticed that it is because of join query. In magento 2.1.x, it was good. Issue is occuring in Magento 2.2.

Other point:

In Magento 2.2, product listing page is reloads twice by default. I have tried it by echo and it display 2 times. So I hope it may be issue.

Please help!

Answer 1

In your stock condition just remove alias name csi and try, It's work for me.

if ($this->getCurrentOrder() == 'stock') {
    $this->_collection->getSelect()
        ->joinLeft(
                'cataloginventory_stock_item',
                'e.entity_id = cataloginventory_stock_item .product_id',
                'cataloginventory_stock_item .qty AS quantity'
        )
    ->group('e.entity_id')
    ->order('quantity ' .$this->getCurrentDirectionReverse());
}