Deleting disabled category forces category flat and catalog search re-indexed fully

app/code/Magento/Catalog/Model/Category.php

@@ -1159,7 +1159,10 @@ public function reindex()
      */
     public function afterDeleteCommit()
     {
-        $this->reindex();
+        if ($this->getIsActive() || $this->getDeletedChildrenIds()) {
+            $this->reindex();
+        }
+
         return parent::afterDeleteCommit();
     }
 

app/code/Magento/Catalog/Model/ResourceModel/Category.php

@@ -232,7 +232,10 @@ protected function _beforeDelete(\Magento\Framework\DataObject $object)
      */
     protected function _afterDelete(DataObject $object)
     {
-        $this->indexerProcessor->markIndexerAsInvalid();
+        if ($object->getIsActive() || $object->getDeletedChildrenIds()) {
+            $this->indexerProcessor->markIndexerAsInvalid();
+        }
+
         return parent::_afterDelete($object);
     }
 

app/code/Magento/CatalogSearch/Model/Indexer/Fulltext/Model/Plugin/Category.php

@@ -9,6 +9,7 @@
 
 use Magento\Catalog\Model\ResourceModel\Category as Resource;
 use Magento\CatalogSearch\Model\Indexer\Fulltext\Processor;
+use Magento\Framework\DataObject;
 
 /**
  * Perform indexer invalidation after a category delete.
@@ -33,12 +34,15 @@ public function __construct(Processor $fulltextIndexerProcessor)
      *
      * @param Resource $subjectCategory
      * @param Resource $resultCategory
+     * @param DataObject $object
      * @return Resource
      * @SuppressWarnings(PHPMD.UnusedFormalParameter)
      */
-    public function afterDelete(Resource $subjectCategory, Resource $resultCategory) : Resource
+    public function afterDelete(Resource $subjectCategory, Resource $resultCategory, DataObject $object) : Resource
     {
-        $this->fulltextIndexerProcessor->markIndexerAsInvalid();
+        if ($object->getIsActive() || $object->getDeletedChildrenIds()) {
+            $this->fulltextIndexerProcessor->markIndexerAsInvalid();
+        }
 
         return $resultCategory;
     }

dev/tests/integration/testsuite/Magento/Catalog/Model/Indexer/Category/ProductTest.php

@@ -184,7 +184,36 @@ public function testCategoryDelete()
         }
     }
 
-    public function testCategoryCreate()
+
+    /**
+     * Verify that indexer still valid after deleting inactive category
+     *
+     * @magentoAppArea adminhtml
+     * @magentoDataFixture Magento/Catalog/_files/categories_disabled.php
+     *
+     * @return void
+     */
+    public function testDeleteInactiveCategory(): void
+    {
+        $this->indexer->reindexAll();
+        $isInvalidIndexer = $this->indexer->isInvalid();
+
+        $this->categoryRepository->deleteByIdentifier(8);
+
+        $state = $this->indexer->getState();
+        $state->loadByIndexer($this->indexer->getId());
+        $status = $state->getStatus();
+
+        $this->assertFalse($isInvalidIndexer);
+        $this->assertEquals(StateInterface::STATUS_VALID, $status);
+    }
+
+    /**
+     * Create category
+     *
+     * @return void
+     */
+    public function testCategoryCreate(): void
     {
         $this->testReindexAll();
         $categories = $this->getCategories(4);

dev/tests/integration/testsuite/Magento/CatalogSearch/Model/Indexer/Fulltext/Model/Plugin/CategoryTest.php

@@ -9,10 +9,16 @@
 
 use Magento\Catalog\Api\CategoryRepositoryInterface;
 use Magento\Catalog\Model\Category;
+use Magento\Catalog\Model\ResourceModel\Category\CollectionFactory as CategoryCollectionFactory;
 use Magento\CatalogSearch\Model\Indexer\Fulltext\Processor;
+use Magento\Framework\Indexer\StateInterface;
 use Magento\TestFramework\Helper\Bootstrap;
+use PHPUnit\Framework\TestCase;
 
-class CategoryTest extends \PHPUnit\Framework\TestCase
+/**
+ * Test for category repository plugin
+ */
+class CategoryTest extends TestCase
 {
     /**
      * @var Processor
@@ -24,10 +30,19 @@ class CategoryTest extends \PHPUnit\Framework\TestCase
      */
     private $categoryRepository;
 
+    /**
+     * @var CategoryCollectionFactory
+     */
+    private $categoryCollectionFactory;
+
+    /**
+     * @inheritDoc
+     */
     protected function setUp(): void
     {
         $this->indexerProcessor = Bootstrap::getObjectManager()->create(Processor::class);
         $this->categoryRepository = Bootstrap::getObjectManager()->create(CategoryRepositoryInterface::class);
+        $this->categoryCollectionFactory = Bootstrap::getObjectManager()->create(CategoryCollectionFactory::class);
     }
 
     /**
@@ -47,22 +62,22 @@ public function testIndexerInvalidatedAfterCategoryDelete()
         $status = $state->getStatus();
 
         $this->assertTrue($isIndexerValid);
-        $this->assertEquals(\Magento\Framework\Indexer\StateInterface::STATUS_INVALID, $status);
+        $this->assertEquals(StateInterface::STATUS_INVALID, $status);
     }
 
     /**
+     * Returns categories
+     *
      * @param int $count
      * @return Category[]
      */
-    private function getCategories($count)
+    private function getCategories(int $count): array
     {
-        /** @var Category $category */
-        $category = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create(
-            \Magento\Catalog\Model\Category::class
-        );
-
-        $result = $category->getCollection()->addAttributeToSelect('name')->getItems();
-        $result = array_slice($result, 2);
+        $collection = $this->categoryCollectionFactory->create()
+            ->addAttributeToSelect('name')
+            ->addAttributeToSelect('is_active')
+            ->getItems();
+        $result = array_slice($collection, 2);
 
         return array_slice($result, 0, $count);
     }