MAGETWO-61120: Tax and Order total not correct when discount is applied

Author: Alex Paliarush

app/code/Magento/Tax/Model/Config.php

@@ -23,7 +23,7 @@ class Config
 
     const XML_PATH_TAX_NOTIFICATION_IGNORE_PRICE_DISPLAY = 'tax/notification/ignore_price_display';
 
-    const XML_PATH_TAX_NOTIFICATION_IGNORE_PRICE_EXCLUDING_TAX_SETTINGS = 'tax/notification/ignore_price_excluding_tax';
+    const XML_PATH_TAX_NOTIFICATION_IGNORE_APPLY_DISCOUNT = 'tax/notification/ignore_apply_discount';
 
     const XML_PATH_TAX_NOTIFICATION_INFO_URL = 'tax/notification/info_url';
 
@@ -764,18 +764,19 @@ public function crossBorderTradeEnabled($store = null)
     }
 
     /**
-     * Check if admin notification about possible issues related to tax display settings should be ignored.
+     * Check if admin notification related to misconfiguration of "Apply Discount On Prices" should be ignored.
      *
-     * For the case when prices under "Calculation Settings" are set to "Excluding Tax"
-     * and at the same time some of price display settings are set to "Including Tax"
+     * Warning is displayed in case when "Catalog Prices" = "Excluding Tax"
+     * AND "Apply Discount On Prices" = "Including Tax"
+     * AND "Apply Customer Tax" = "After Discount"
      *
      * @param null|string|Store $store
      * @return bool
      */
-    public function isWrongPriceExcludingTaxSettingsIgnored($store = null)
+    public function isWrongApplyDiscountSettingIgnored($store = null)
     {
         return (bool)$this->_scopeConfig->getValue(
-            self::XML_PATH_TAX_NOTIFICATION_IGNORE_PRICE_EXCLUDING_TAX_SETTINGS,
+            self::XML_PATH_TAX_NOTIFICATION_IGNORE_APPLY_DISCOUNT,
             \Magento\Store\Model\ScopeInterface::SCOPE_STORE,
             $store
         );

app/code/Magento/Tax/Model/Config/Notification.php

@@ -52,7 +52,7 @@ public function afterSave()
         if ($this->isValueChanged()) {
             $this->_resetNotificationFlag(Config::XML_PATH_TAX_NOTIFICATION_IGNORE_DISCOUNT);
             $this->_resetNotificationFlag(Config::XML_PATH_TAX_NOTIFICATION_IGNORE_PRICE_DISPLAY);
-            $this->_resetNotificationFlag(Config::XML_PATH_TAX_NOTIFICATION_IGNORE_PRICE_EXCLUDING_TAX_SETTINGS);
+            $this->_resetNotificationFlag(Config::XML_PATH_TAX_NOTIFICATION_IGNORE_APPLY_DISCOUNT);
         }
         return parent::afterSave();
     }

app/code/Magento/Tax/Model/System/Message/Notification/AdminPriceExcludingTax.php renamed to app/code/Magento/Tax/Model/System/Message/Notification/ApplyDiscountOnPrices.php

@@ -8,12 +8,13 @@
 use Magento\Tax\Model\Config;
 
 /**
- * Class allows to show admin notification about possible issues related to tax calculation and display settings.
+ * Class allows to show admin notification about possible issues related to "Apply Discount On Prices" setting.
  *
- * For the case when prices under "Calculation Settings" are set to "Excluding Tax"
- * and at the same time some of price display settings are set to "Including Tax"
+ * Warning is displayed in case when "Catalog Prices" = "Excluding Tax"
+ * AND "Apply Discount On Prices" = "Including Tax"
+ * AND "Apply Customer Tax" = "After Discount"
  */
-class AdminPriceExcludingTax implements \Magento\Tax\Model\System\Message\NotificationInterface
+class ApplyDiscountOnPrices implements \Magento\Tax\Model\System\Message\NotificationInterface
 {
     /**
      * @var \Magento\Store\Model\StoreManagerInterface
@@ -58,15 +59,15 @@ public function __construct(
      */
     public function getIdentity()
     {
-        return 'TAX_NOTIFICATION_PRICE_EXCLUDING_TAX';
+        return 'TAX_NOTIFICATION_APPLY_DISCOUNT';
     }
 
     /**
      * {@inheritdoc}
      */
     public function isDisplayed()
     {
-        if (!$this->taxConfig->isWrongPriceExcludingTaxSettingsIgnored() && $this->getStoresWithWrongSettings()) {
+        if (!$this->taxConfig->isWrongApplyDiscountSettingIgnored() && $this->getStoresWithWrongSettings()) {
             return true;
         }
         return false;
@@ -81,14 +82,14 @@ public function getText()
 
         if ($this->isDisplayed()) {
             $messageDetails .= '<strong>';
-            $messageDetails .= __('Current tax configuration can result in rounding errors and discount calculation errors. ');
+            $messageDetails .= __('If you want to apply discount on prices including tax and apply customer tax after discount, you must set Catalog Prices to “Including Price”. ');
             $messageDetails .= '</strong><p>';
             $messageDetails .= __('Store(s) affected: ');
             $messageDetails .= implode(', ', $this->getStoresWithWrongSettings());
             $messageDetails .= '</p><p>';
             $messageDetails .= __(
                 'Click on the link to <a href="%1">ignore this notification</a>',
-                $this->urlBuilder->getUrl('tax/tax/ignoreTaxNotification', ['section' => 'price_excluding_tax'])
+                $this->urlBuilder->getUrl('tax/tax/ignoreTaxNotification', ['section' => 'apply_discount'])
             );
             $messageDetails .= "</p>";
         }
@@ -106,7 +107,7 @@ public function getSeverity()
     }
 
     /**
-     * Return list of store names which have incompatible tax calculation and tax display settings.
+     * Return list of store names which have invalid settings.
      *
      * @return array
      */
@@ -127,56 +128,15 @@ private function getStoresWithWrongSettings()
     }
 
     /**
-     * Check if tax calculation and tax display settings are compatible.
+     * Check if settings are valid.
      *
      * @param null|int|bool|string|\Magento\Store\Model\Store $store $store
      * @return bool false if settings are incorrect
      */
     private function checkSettings($store = null)
     {
-        $adminCatalogPricesExcludeTax = !$this->taxConfig->priceIncludesTax($store)
-            || !$this->taxConfig->shippingPriceIncludesTax($store);
-        $displayPricesWhichIncludeTax = $this->hasCatalogDisplaySettingsWhichIncludeTax($store)
-            || $this->hasCartDisplaySettingsWhichIncludeTax($store)
-            || $this->hasSalesDisplaySettingsWhichIncludeTax($store);
-        return !($adminCatalogPricesExcludeTax && $displayPricesWhichIncludeTax);
-    }
-
-    /**
-     * Check if there are any price display settings for catalog with values other than "Excluding tax"
-     *
-     * @param null|int|bool|string|\Magento\Store\Model\Store $store $store
-     * @return bool
-     */
-    private function hasCatalogDisplaySettingsWhichIncludeTax($store = null)
-    {
-        return $this->taxConfig->getPriceDisplayType($store) !== Config::DISPLAY_TYPE_EXCLUDING_TAX
-            || $this->taxConfig->getShippingPriceDisplayType($store) !== Config::DISPLAY_TYPE_EXCLUDING_TAX;
-    }
-
-    /**
-     * Check if there are any price display settings for cart with values other than "Excluding tax"
-     *
-     * @param null|int|bool|string|\Magento\Store\Model\Store $store $store
-     * @return bool
-     */
-    private function hasCartDisplaySettingsWhichIncludeTax($store = null)
-    {
-        return !$this->taxConfig->displayCartPricesExclTax($store)
-            || !$this->taxConfig->displayCartSubtotalExclTax($store)
-            || !$this->taxConfig->displayCartShippingExclTax($store);
-    }
-
-    /**
-     * Check if there are any price display settings for orders, invoices, credit memos with values not "Excluding tax"
-     *
-     * @param null|int|bool|string|\Magento\Store\Model\Store $store $store
-     * @return bool
-     */
-    private function hasSalesDisplaySettingsWhichIncludeTax($store = null)
-    {
-        return !$this->taxConfig->displaySalesPricesExclTax($store)
-            || !$this->taxConfig->displaySalesSubtotalExclTax($store)
-            || !$this->taxConfig->displaySalesShippingExclTax($store);
+        return $this->taxConfig->priceIncludesTax($store)
+            || !$this->taxConfig->applyTaxAfterDiscount($store)
+            || !$this->taxConfig->discountTax($store);
     }
 }