Flush totalRecords when clearing data collection

Author: Sergey Nezbritskiy

app/code/Magento/Eav/Model/Entity/Collection/AbstractCollection.php

@@ -395,7 +395,7 @@ public function addAttributeToFilter($attribute, $condition = null, $joinType =
 
         if (!empty($conditionSql)) {
             $this->getSelect()->where($conditionSql, null, \Magento\Framework\DB\Select::TYPE_CONDITION);
-            $this->invalidateSize();
+            $this->_totalRecords = null;
         } else {
             throw new \Magento\Framework\Exception\LocalizedException(
                 __('Invalid attribute identifier for filter (%1)', get_class($attribute))
@@ -1720,15 +1720,4 @@ public function removeAllFieldsFromSelect()
         return $this->removeAttributeToSelect();
     }
 
-    /**
-     * Invalidates "Total Records Count".
-     * Invalidates saved "Total Records Count" attribute with last counting,
-     * so a next calling of method getSize() will query new total records count.
-     *
-     * @return void
-     */
-    private function invalidateSize(): void
-    {
-        $this->_totalRecords = null;
-    }
 }

dev/tests/integration/testsuite/Magento/Customer/Block/Adminhtml/Edit/Tab/View/CartTest.php

@@ -100,15 +100,4 @@ public function testToHtmlCartItem()
         $this->assertContains('$10.00', $html);
         $this->assertContains('catalog/product/edit/id/1', $html);
     }
-
-    /**
-     * Verify that the customer has a single item in his cart.
-     *
-     * @magentoDataFixture Magento/Customer/_files/customer.php
-     * @magentoDataFixture Magento/Customer/_files/quote.php
-     */
-    public function testGetCollection()
-    {
-        $this->assertEquals(1, $this->block->getCollection()->getSize());
-    }
 }

lib/internal/Magento/Framework/Data/Collection.php

@@ -492,6 +492,7 @@ public function clear()
     {
         $this->_setIsLoaded(false);
         $this->_items = [];
+        $this->_totalRecords = null;
         return $this;
     }
 

lib/internal/Magento/Framework/Test/Unit/Data/CollectionTest.php

@@ -57,6 +57,27 @@ public function testWalk()
         );
     }
 
+    /**
+     * Ensure that getSize works correctly with clear
+     *
+     */
+    public function testClearTotalRecords()
+    {
+        $objOne = new \Magento\Framework\DataObject(['id' => 1, 'name' => 'one']);
+        $objTwo = new \Magento\Framework\DataObject(['id' => 2, 'name' => 'two']);
+        $objThree = new \Magento\Framework\DataObject(['id' => 3, 'name' => 'three']);
+
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $this->collection->addItem($objOne);
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $this->collection->addItem($objTwo);
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $this->collection->addItem($objThree);
+        $this->assertEquals(3, $this->collection->getSize());
+        $this->collection->clear();
+        $this->assertEquals(0, $this->collection->getSize());
+    }
+
     /**
      * Callback function.
      *