From 23d59bba609575f5a9e8f32737ab3e3ad1ca852d Mon Sep 17 00:00:00 2001
From: catch <catch@35733.no-reply.drupal.org>
Date: Wed, 9 Jun 2021 14:06:35 +0100
Subject: [PATCH] Issue #3122056 by Wim Leers, mohit_aghera, Kristen Pol: Do
 not track viewing history for unsaved entities, nor when previewing existing
 entities

---
 core/modules/history/history.module            |  3 +++
 .../tests/src/Functional/HistoryTest.php       | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/core/modules/history/history.module b/core/modules/history/history.module
index 5495d539fff..02dd964fd7c 100644
--- a/core/modules/history/history.module
+++ b/core/modules/history/history.module
@@ -135,6 +135,9 @@ function history_cron() {
  * Implements hook_ENTITY_TYPE_view_alter() for node entities.
  */
 function history_node_view_alter(array &$build, EntityInterface $node, EntityViewDisplayInterface $display) {
+  if ($node->isNew() || isset($node->in_preview)) {
+    return;
+  }
   // Update the history table, stating that this user viewed this node.
   if ($display->getOriginalMode() === 'full') {
     $build['#cache']['contexts'][] = 'user.roles:authenticated';
diff --git a/core/modules/history/tests/src/Functional/HistoryTest.php b/core/modules/history/tests/src/Functional/HistoryTest.php
index e89fc8e988e..6117a2dd80a 100644
--- a/core/modules/history/tests/src/Functional/HistoryTest.php
+++ b/core/modules/history/tests/src/Functional/HistoryTest.php
@@ -49,6 +49,7 @@ class HistoryTest extends BrowserTestBase {
 
     $this->user = $this->drupalCreateUser([
       'create page content',
+      'edit own page content',
       'access content',
     ]);
     $this->drupalLogin($this->user);
@@ -103,6 +104,11 @@ class HistoryTest extends BrowserTestBase {
   public function testHistory() {
     $nid = $this->testNode->id();
 
+    // Verify that previews of new entities do not create the history.
+    $this->drupalGet("node/add/page");
+    $this->submitForm(['title[0][value]' => 'Unsaved page'], 'Preview');
+    $this->assertArrayNotHasKey('ajaxPageState', $this->getDrupalSettings());
+
     // Retrieve "last read" timestamp for test node, for the current user.
     $response = $this->getNodeReadTimestamps([$nid]);
     $this->assertEquals(200, $response->getStatusCode());
@@ -134,6 +140,11 @@ class HistoryTest extends BrowserTestBase {
     $response = $this->getNodeReadTimestamps([]);
     $this->assertEquals(404, $response->getStatusCode());
 
+    // Verify that previews of existing entities do not update the history.
+    $this->drupalGet("node/$nid/edit");
+    $this->submitForm([], 'Preview');
+    $this->assertArrayNotHasKey('ajaxPageState', $this->getDrupalSettings());
+
     // Accessing either endpoint as the anonymous user should return a 403.
     $this->drupalLogout();
     $response = $this->getNodeReadTimestamps([$nid]);
@@ -142,6 +153,13 @@ class HistoryTest extends BrowserTestBase {
     $this->assertEquals(403, $response->getStatusCode());
     $response = $this->markNodeAsRead($nid);
     $this->assertEquals(403, $response->getStatusCode());
+
+    // Additional check to ensure that we did not forget to verify anything.
+    $rows = \Drupal::database()->query('SELECT * FROM {history}')->fetchAll();
+    $this->assertCount(1, $rows);
+    $this->assertSame($this->user->id(), $rows[0]->uid);
+    $this->assertSame($this->testNode->id(), $rows[0]->nid);
+    $this->assertSame($timestamp, (int) $rows[0]->timestamp);
   }
 
 }