Update comments, use short array syntax and fix redundancy.

lib/Doctrine/DBAL/Cache/ArrayStatement.php

@@ -139,7 +139,7 @@ class ArrayStatement implements \IteratorAggregate, ResultStatement
     {
         $row = $this->fetch(PDO::FETCH_NUM);
 
-        // TODO: verify this is correct behavior
+        // TODO: verify that return false is the correct behavior
         return $row[$columnIndex] ?? false;
     }
 }

lib/Doctrine/DBAL/Cache/ResultCacheStatement.php

@@ -196,7 +196,7 @@ class ResultCacheStatement implements \IteratorAggregate, ResultStatement
     {
         $row = $this->fetch(PDO::FETCH_NUM);
 
-        // TODO: verify this is correct behavior
+        // TODO: verify that return false is the correct behavior
         return $row[$columnIndex] ?? false;
     }
 

lib/Doctrine/DBAL/DriverManager.php

@@ -153,7 +153,7 @@ final class DriverManager
             self::_checkParams($params);
         }
 
-        $className = $params['driverClass'] ?? $className = self::$_driverMap[$params['driver']];
+        $className = $params['driverClass'] ?? self::$_driverMap[$params['driver']];
 
         $driver = new $className();
 
@@ -393,11 +393,11 @@ final class DriverManager
             // URL schemes must not contain underscores, but dashes are ok
             $driver = str_replace('-', '_', $url['scheme']);
 
-            // The requested driver from the URL scheme takes precedence
-            // over the default driver from the connection parameters (if any).
+            // The requested driver from the URL scheme takes precedence over the
+            // default driver from the connection parameters. If the driver is
+            // an alias (e.g. "postgres"), map it to the actual name ("pdo-pgsql").
+            // Otherwise, let checkParams decide later if the driver exists.
             $params['driver'] = self::$driverSchemeAliases[$driver] ?? $driver;
-            // use alias like "postgres", else we just let checkParams decide later
-            // if the driver exists (for literal "pdo-pgsql" etc)
 
             return $params;
         }

tests/Doctrine/Tests/DBAL/Functional/Schema/SchemaManagerFunctionalTestCase.php

@@ -873,7 +873,7 @@ class SchemaManagerFunctionalTestCase extends \Doctrine\Tests\DbalFunctionalTest
      */
     protected function createTestTable($name = 'test_table', $data = array())
     {
-        $options = $data['options'] ?? array();
+        $options = $data['options'] ?? [];
 
         $table = $this->getTestTable($name, $options);