Moved adjustments to plugin.

Author: novikor

app/code/Magento/ConfigurableProduct/Plugin/SalesRule/Model/Rule/Condition/Product.php

@@ -0,0 +1,54 @@
+<?php declare(strict_types=1);
+
+namespace Magento\ConfigurableProduct\Plugin\SalesRule\Model\Rule\Condition;
+
+use Magento\ConfigurableProduct\Model\Product\Type\Configurable;
+
+/**
+ * Class Product
+ *
+ * @package Magento\ConfigurableProduct\Plugin\SalesRule\Model\Rule\Condition
+ */
+class Product
+{
+    /**
+     * @param \Magento\SalesRule\Model\Rule\Condition\Product $subject
+     * @param \Magento\Framework\Model\AbstractModel          $model
+     */
+    public function beforeValidate(
+        \Magento\SalesRule\Model\Rule\Condition\Product $subject,
+        \Magento\Framework\Model\AbstractModel $model
+    ) {
+        $model->setProduct(
+            $this->getProductToValidate($subject, $model)
+        );
+    }
+
+
+    /**
+     * @param \Magento\SalesRule\Model\Rule\Condition\Product $subject
+     * @param \Magento\Framework\Model\AbstractModel          $model
+     *
+     * @return \Magento\Catalog\Api\Data\ProductInterface|\Magento\Catalog\Model\Product
+     */
+    private function getProductToValidate(
+        \Magento\SalesRule\Model\Rule\Condition\Product $subject,
+        \Magento\Framework\Model\AbstractModel $model
+    ) {
+        /** @var \Magento\Catalog\Model\Product $product */
+        $product = $model->getProduct();
+
+        $attrCode = $subject->getAttribute();
+
+        /* Check for attributes which are not available for configurable products */
+        if ($product->getTypeId() == Configurable::TYPE_CODE && !$product->hasData($attrCode)) {
+            /** @var \Magento\Catalog\Model\AbstractModel $childProduct */
+            $childProduct = current($model->getChildren())->getProduct();
+            if ($childProduct->hasData($attrCode)) {
+                $product = $childProduct;
+            }
+        }
+
+        return $product;
+    }
+}

app/code/Magento/ConfigurableProduct/composer.json

@@ -19,6 +19,7 @@
     "suggest": {
         "magento/module-webapi": "100.2.*",
         "magento/module-sales": "101.0.*",
+        "magento/module-sales-rule": "101.0.*",
         "magento/module-product-video": "100.2.*",
         "magento/module-configurable-sample-data": "Sample Data version:100.2.*",
         "magento/module-product-links-sample-data": "Sample Data version:100.2.*"

app/code/Magento/ConfigurableProduct/etc/di.xml

@@ -221,4 +221,7 @@
     <type name="Magento\Catalog\Model\Product">
         <plugin name="product_identities_extender" type="Magento\ConfigurableProduct\Model\Plugin\ProductIdentitiesExtender" />
     </type>
+    <type name="Magento\SalesRule\Model\Rule\Condition\Product">
+        <plugin name="apply_rule_on_configurable_children" type="Magento\ConfigurableProduct\Plugin\SalesRule\Model\Rule\Condition\Product" />
+    </type>
 </config>