Prestashop 1.6.X - Fix attribute color list doesn't show on product list if turning on smarty cache

FrontController.php

<?php
class FrontController extends FrontControllerCore
{
    public function addColorsToProductList(&$products)
    {
        if (!is_array($products) || !count($products) || !file_exists(_PS_THEME_DIR_.'product-list-colors.tpl')) {
            return;
        }

        $products_need_cache = array();
        foreach ($products as &$product) {
            if (!$this->isCached(_PS_THEME_DIR_.'product-list-colors.tpl', $this->getColorsListCacheId($product['id_product']))) {
                $products_need_cache[] = (int)$product['id_product'];
            }else{
                $product['color_list'] = $this->context->smarty->createTemplate(_PS_THEME_DIR_.'product-list-colors.tpl', $this->getColorsListCacheId($product['id_product']))->fetch();
            }
        }

        unset($product);

        $colors = false;
        if (count($products_need_cache)) {
            $colors = Product::getAttributesColorList($products_need_cache);
			Tools::enableCache();
			foreach ($products as &$product) {
				if (in_array($product['id_product'], $products_need_cache)){
					$tpl = $this->context->smarty->createTemplate(_PS_THEME_DIR_.'product-list-colors.tpl', $this->getColorsListCacheId($product['id_product']));
					if (isset($colors[$product['id_product']])) {
						$tpl->assign(array(
							'id_product'  => $product['id_product'],
							'colors_list' => $colors[$product['id_product']],
							'link'        => Context::getContext()->link,
							'img_col_dir' => _THEME_COL_DIR_,
							'col_img_dir' => _PS_COL_IMG_DIR_
						));
						$product['color_list'] = $tpl->fetch(_PS_THEME_DIR_.'product-list-colors.tpl', $this->getColorsListCacheId($product['id_product']));
					} else {
						$product['color_list'] = '';
					}
				}
			}
			Tools::restoreCacheSettings();
        }

    }
}

how yo use:

1. Download the gist and make sure the filename is FrontController.php and place it in overrides/classes/controller/
2. Delete class_index.php in /cache/
3. Clear store cache

Original Author: iTiaNex
Source: PrestaShop/PrestaShop#7876 (comment)