Issue #1476782 by daffie, droplet, donquixote, Katiemouse, Lendude, lnunesbr, ekl1773, init90, jhedstrom, catch, clemens.tolboom, amateescu: DatabaseStatementPrefetch::current PHP function array_unshift() are used incorrectly

(cherry picked from commit 6add1ca7a3)

core/lib/Drupal/Core/Database/StatementPrefetch.php

@@ -282,7 +282,7 @@ class StatementPrefetch implements \Iterator, StatementInterface {
         case \PDO::FETCH_OBJ:
           return (object) $this->currentRow;
         case \PDO::FETCH_CLASS | \PDO::FETCH_CLASSTYPE:
-          $class_name = array_unshift($this->currentRow);
+          $class_name = array_shift($this->currentRow);
           // Deliberate no break.
         case \PDO::FETCH_CLASS:
           if (!isset($class_name)) {

core/modules/system/tests/modules/database_test/database_test.install

@@ -54,6 +54,44 @@ function database_test_schema() {
     ],
   ];
 
+  $schema['test_classtype'] = [
+    'description' => 'A duplicate version of the test table, used for fetch_style PDO::FETCH_CLASSTYPE tests.',
+    'fields' => [
+      'classname' => [
+        'description' => "A custom class name",
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ],
+      'name' => [
+        'description' => "A person's name",
+        'type' => 'varchar',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ],
+      'age' => [
+        'description' => "The person's age",
+        'type' => 'int',
+        'unsigned' => TRUE,
+        'not null' => TRUE,
+        'default' => 0,
+      ],
+      'job' => [
+        'description' => "The person's job",
+        'type' => 'varchar_ascii',
+        'length' => 255,
+        'not null' => TRUE,
+        'default' => '',
+      ],
+    ],
+    'primary key' => ['job'],
+    'indexes' => [
+      'ages' => ['age'],
+    ],
+  ];
+
   // This is an alternate version of the same table that is structured the same
   // but has a non-serial Primary Key.
   $schema['test_people'] = [

core/tests/Drupal/KernelTests/Core/Database/DatabaseTestBase.php

@@ -27,6 +27,7 @@ abstract class DatabaseTestBase extends KernelTestBase {
     $this->connection = Database::getConnection();
     $this->installSchema('database_test', [
       'test',
+      'test_classtype',
       'test_people',
       'test_people_copy',
       'test_one_blob',
@@ -100,6 +101,15 @@ abstract class DatabaseTestBase extends KernelTestBase {
       ])
       ->execute();
 
+    $connection->insert('test_classtype')
+      ->fields([
+        'classname' => 'Drupal\Tests\system\Functional\Database\FakeRecord',
+        'name' => 'Kay',
+        'age' => 26,
+        'job' => 'Web Developer',
+      ])
+      ->execute();
+
     $connection->insert('test_people')
       ->fields([
         'name' => 'Meredith',

core/tests/Drupal/KernelTests/Core/Database/FetchTest.php

@@ -80,6 +80,27 @@ class FetchTest extends DatabaseTestBase {
     $this->assertIdentical(count($records), 1, 'There is only one record.');
   }
 
+  /**
+   * Confirms that we can fetch a record into a new instance of a custom class.
+   * The name of the class is determined from a value of the first column.
+   *
+   * @see \Drupal\Tests\system\Functional\Database\FakeRecord
+   */
+  public function testQueryFetchClasstype() {
+    $records = [];
+    $result = $this->connection->query('SELECT classname, name, job FROM {test_classtype} WHERE age = :age', [':age' => 26], ['fetch' => \PDO::FETCH_CLASS | \PDO::FETCH_CLASSTYPE]);
+    foreach ($result as $record) {
+      $records[] = $record;
+      if ($this->assertTrue($record instanceof FakeRecord, 'Record is an object of class FakeRecord.')) {
+        $this->assertSame('Kay', $record->name, 'Kay is found.');
+        $this->assertSame('Web Developer', $record->job, 'A 26 year old Web Developer.');
+      }
+      $this->assertFalse(isset($record->classname), 'Classname field not found, as intended.');
+    }
+
+    $this->assertCount(1, $records, 'There is only one record.');
+  }
+
   /**
    * Confirms that we can fetch a record into an indexed array explicitly.
    */