Magento 2.3 - Set max compare products to 3

Question

I want to limit the max products to compare to 3. I tried to create this module: https://magento.stackexchange.com/a/159543/16894

But it seems that this does not work with Magento 2.3, because I do not get any message and still can add more than 3 items.

How can I achieve this?

Answer 1

I have tuned the answer that you did find faulty. The change is minor but hopefully it resolve your issue.

public function aroundExecute(
        \Magento\Catalog\Controller\Product\Compare\Add $subject,
        callable $proceed
    ) {
        $count = $this->helper->getItemCount();
        if ($count >= self::$LIMIT_TO_COMPARE_PRODUCTS) {
            $this->messageManager->addErrorMessage(
                sprintf('Only up to %s items can be added to the comparison list', self::$LIMIT_TO_COMPARE_PRODUCTS)
            );

            /** @var \Magento\Framework\Controller\Result\Redirect $resultRedirect */
            $resultRedirect = $this->resultRedirectFactory->create();
            return $resultRedirect->setRefererOrBaseUrl();
        }

        return $proceed();
    }