Issue #3490200 by mondrake, daffie, alexpott:...

Issue #3490200 by mondrake, daffie, alexpott: StatementPrefetchIterator::fetchCol fails silently if the column index is out of range

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

@@ -168,6 +168,9 @@ public function fetchAll($mode = NULL, $column_index = NULL, $constructor_argume
    *
    * @return array
    *   An indexed array, or an empty array if there is no result set.
+   *
+   * @throws \ValueError
+   *   If there is at least one record but the column index is not defined.
    */
   public function fetchCol($index = 0);
 

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

@@ -256,20 +256,24 @@ public function fetch($fetch_style = NULL, $cursor_orientation = \PDO::FETCH_ORI
   }
 
   /**
-   * {@inheritdoc}
+   * @deprecated in drupal:11.2.0 and is removed from drupal:12.0.0. Use
+   *   ::fetchField() instead.
+   *
+   * @see https://www.drupal.org/node/3490312
    */
   public function fetchColumn($index = 0) {
-    if ($row = $this->fetch(\PDO::FETCH_ASSOC)) {
-      return $this->assocToColumn($row, $this->columnNames, $index);
-    }
-    return FALSE;
+    @trigger_error(__METHOD__ . '() is deprecated in drupal:11.2.0 and is removed from drupal:12.0.0. Use ::fetchField() instead. See https://www.drupal.org/node/3490312', E_USER_DEPRECATED);
+    return $this->fetchField($index);
   }
 
   /**
    * {@inheritdoc}
    */
   public function fetchField($index = 0) {
-    return $this->fetchColumn($index);
+    if ($row = $this->fetch(\PDO::FETCH_ASSOC)) {
+      return $this->assocToColumn($row, $this->columnNames, $index);
+    }
+    return FALSE;
   }
 
   /**
@@ -319,14 +323,11 @@ public function fetchAll($mode = NULL, $column_index = NULL, $constructor_argume
    * {@inheritdoc}
    */
   public function fetchCol($index = 0) {
-    if (isset($this->columnNames[$index])) {
-      $result = [];
-      while ($row = $this->fetch(\PDO::FETCH_ASSOC)) {
-        $result[] = $row[$this->columnNames[$index]];
-      }
-      return $result;
+    $result = [];
+    while (($columnValue = $this->fetchField($index)) !== FALSE) {
+      $result[] = $columnValue;
     }
-    return [];
+    return $result;
   }
 
   /**

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

@@ -6,7 +6,9 @@
 
 use Drupal\Core\Database\RowCountException;
 use Drupal\Core\Database\StatementInterface;
+use Drupal\Core\Database\StatementPrefetchIterator;
 use Drupal\Tests\system\Functional\Database\FakeRecord;
+use PHPUnit\Framework\Attributes\IgnoreDeprecations;
 
 /**
  * Tests the Database system's various fetch capabilities.
@@ -33,6 +35,28 @@ public function testQueryFetchDefault(): void {
     $this->assertCount(1, $records, 'There is only one record.');
   }
 
+  /**
+   * Confirms that we can fetch a single column value.
+   */
+  public function testQueryFetchColumn(): void {
+    $statement = $this->connection
+      ->query('SELECT [name] FROM {test} WHERE [age] = :age', [':age' => 25]);
+    $statement->setFetchMode(\PDO::FETCH_COLUMN, 0);
+    $this->assertSame('John', $statement->fetch());
+  }
+
+  /**
+   * Confirms that an out of range index throws an error.
+   */
+  public function testQueryFetchColumnOutOfRange(): void {
+    $this->expectException(\ValueError::class);
+    $this->expectExceptionMessage('Invalid column index');
+    $statement = $this->connection
+      ->query('SELECT [name] FROM {test} WHERE [age] = :age', [':age' => 25]);
+    $statement->setFetchMode(\PDO::FETCH_COLUMN, 200);
+    $statement->fetch();
+  }
+
   /**
    * Confirms that we can fetch a record to an object explicitly.
    */
@@ -161,6 +185,62 @@ public function testQueryFetchCol(): void {
     }
   }
 
+  /**
+   * Tests ::fetchCol() for edge values returned.
+   */
+  public function testQueryFetchColEdgeCases(): void {
+    $this->connection->insert('test_null')
+      ->fields([
+        'name' => 'Foo',
+        'age' => 0,
+      ])
+      ->execute();
+
+    $this->connection->insert('test_null')
+      ->fields([
+        'name' => 'Bar',
+        'age' => NULL,
+      ])
+      ->execute();
+
+    $this->connection->insert('test_null')
+      ->fields([
+        'name' => 'Qux',
+        'age' => (int) FALSE,
+      ])
+      ->execute();
+
+    $statement = $this->connection->select('test_null')
+      ->fields('test_null', ['age'])
+      ->orderBy('id')
+      ->execute();
+
+    $this->assertSame(['0', NULL, '0'], $statement->fetchCol());
+
+    // Additional fetch returns FALSE since the result set is finished.
+    $this->assertFalse($statement->fetchField());
+  }
+
+  /**
+   * Confirms that an out of range index in fetchCol() throws an error.
+   */
+  public function testQueryFetchColIndexOutOfRange(): void {
+    $this->expectException(\ValueError::class);
+    $this->expectExceptionMessage('Invalid column index');
+    $this->connection
+      ->query('SELECT [name] FROM {test} WHERE [age] > :age', [':age' => 25])
+      ->fetchCol(200);
+  }
+
+  /**
+   * Confirms empty result set prevails on out of range index in fetchCol().
+   */
+  public function testQueryFetchColIndexOutOfRangeOnEmptyResultSet(): void {
+    $this->assertSame([], $this->connection
+      ->query('SELECT [name] FROM {test} WHERE [age] = :age', [':age' => 255])
+      ->fetchCol(200));
+  }
+
   /**
    * Tests ::fetchAllAssoc().
    */
@@ -274,7 +354,7 @@ public function testQueryFetchFieldEdgeCases(): void {
   }
 
   /**
-   * Confirms that an out of range index throws an error.
+   * Confirms that an out of range index in fetchField() throws an error.
    */
   public function testQueryFetchFieldIndexOutOfRange(): void {
     $this->expectException(\ValueError::class);
@@ -285,7 +365,7 @@ public function testQueryFetchFieldIndexOutOfRange(): void {
   }
 
   /**
-   * Confirms that empty result set prevails on out of range index.
+   * Confirms empty result set prevails on out of range index in fetchField().
    */
   public function testQueryFetchFieldIndexOutOfRangeOnEmptyResultSet(): void {
     $this->assertFalse($this->connection
@@ -308,4 +388,18 @@ public function testRowCount(): void {
     $this->assertTrue($exception, 'Exception was thrown');
   }
 
+  /**
+   * Confirms deprecation of StatementPrefetchIterator::fetchColumn().
+   */
+  #[IgnoreDeprecations]
+  public function testLegacyFetchColumn(): void {
+    $statement = $this->connection->query('SELECT [name] FROM {test} WHERE [age] = :age', [':age' => 25]);
+    if (!$statement instanceof StatementPrefetchIterator) {
+      $this->markTestSkipped('This test is for StatementPrefetchIterator statements only.');
+    }
+
+    $this->expectDeprecation('Drupal\Core\Database\StatementPrefetchIterator::fetchColumn() is deprecated in drupal:11.2.0 and is removed from drupal:12.0.0. Use ::fetchField() instead. See https://www.drupal.org/node/3490312');
+    $statement->fetchColumn();
+  }
+
 }