Support for backslashes in default values

It is now possible to use `\`, or other escaped characters, in default
values for a column.

Previously this lead to a confusion when diffing actual and expected
schema leading to perpetual out of sync schema.

lib/Doctrine/DBAL/Platforms/MySqlPlatform.php

@@ -385,7 +385,7 @@ public function getListTableColumnsSQL($table, $database = null)
         }
 
         return "SELECT COLUMN_NAME AS Field, COLUMN_TYPE AS Type, IS_NULLABLE AS `Null`, ".
-               "COLUMN_KEY AS `Key`, COLUMN_DEFAULT AS `Default`, EXTRA AS Extra, COLUMN_COMMENT AS Comment, " .
+               "COLUMN_KEY AS `Key`, TRIM('\'' FROM QUOTE(COLUMN_DEFAULT)) AS `Default`, EXTRA AS Extra, COLUMN_COMMENT AS Comment, " .
                "CHARACTER_SET_NAME AS CharacterSet, COLLATION_NAME AS Collation ".
                "FROM information_schema.COLUMNS WHERE TABLE_SCHEMA = " . $database . " AND TABLE_NAME = " . $table;
     }

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

@@ -180,6 +180,21 @@ public function testDoesNotPropagateDefaultValuesForUnsupportedColumnTypes()
         $this->assertFalse($onlineTable->getColumn('def_blob_null')->getNotnull());
     }
 
+    public function testEscapedDefaultValueMustBePreserved()
+    {
+        $value = "a\\0a\\'a\"a\na\ra\ta\\Za\\\\a";
+
+        $table = new Table('string_escaped_default_value');
+        $table->addColumn('def_string', 'string', array('default' => $value));
+        $this->_sm->dropAndCreateTable($table);
+
+        $onlineTable = $this->_sm->listTableDetails('string_escaped_default_value');
+        $this->assertSame($value, $onlineTable->getColumn('def_string')->getDefault());
+
+        $comparator = new Comparator();
+        $this->assertFalse($comparator->diffTable($table, $onlineTable));
+    }
+
     public function testColumnCollation()
     {
         $table = new Table('test_collation');