MAGETWO-49193: Price field doesn't show currency symbol and validation doesn't work

Author: Bohdan Korablov

app/code/Magento/Catalog/Ui/DataProvider/Product/Form/Modifier/Eav.php

@@ -462,6 +462,25 @@ protected function setupMetaProperties(ProductAttributeInterface $attribute)
         }
 
         $meta = $this->addWysiwyg($attribute, $meta);
+        $meta = $this->customizePriceAttribute($attribute, $meta);
+
+        return $meta;
+    }
+
+    /**
+     * Customize attribute that has price type
+     *
+     * @param ProductAttributeInterface $attribute
+     * @param array $meta
+     * @return array
+     */
+    private function customizePriceAttribute(ProductAttributeInterface $attribute, array $meta)
+    {
+        if ($attribute->getFrontendInput() === 'price') {
+            $meta['arguments']['data']['config']['addbefore'] = $this->locator->getStore()
+                ->getBaseCurrency()
+                ->getCurrencySymbol();
+        }
 
         return $meta;
     }

app/code/Magento/Ui/DataProvider/EavValidationRules.php

@@ -35,6 +35,10 @@ public function build(AbstractAttribute $attribute, array $data)
         if (!empty($data['arguments']['data']['config']['required'])) {
             $rules['required-entry'] = true;
         }
+        if ($attribute->getFrontendInput() === 'price') {
+            $rules['validate-zero-or-greater'] = true;
+        }
+
         $validation = $attribute->getValidateRules();
         if (!empty($validation)) {
             foreach ($validation as $type => $ruleName) {