Description:
------------
When trying to connect to db with a user that is not 'root' and password is empty (user has correct privileges to dbname) PDO throws exception: 

SQLSTATE[HY000] [1044] Access denied for user ''@'localhost' to database 'mydb'

When the supplied username is 'root' and password is empty, the connect succeeds if the db user has empty password, or throws a correct exception:

SQLSTATE[HY000] [1045] Access denied for user 'root'@'localhost' (using password: NO)

The issues has been reproduced on multiple installations with PHP version 5.3.8 and also Mac with MAMP 3.0.3

I wasn't sure if it's a bug and posted on SE here as well: https://stackoverflow.com/questions/22876169/pdo-on-windows-ignores-host-name-and-username-when-password-is-empty



Test script:
---------------
<?php
$host   = "localhost";
$dbname = "mydb";
$user   = "myuser";
$pass   = "";

try {
    $DBH = new PDO("mysql:host={$host};dbname={$dbname};charset=utf8", $user, $pass);
} catch (Exception $e) {
    echo $e->getMessage();
}

Expected result:
----------------
Connection succeeded or exception:

SQLSTATE[HY000] [1045] Access denied for user 'myuser'@'localhost' (using password: NO)

Actual result:
--------------
SQLSTATE[HY000] [1044] Access denied for user ''@'localhost' to database 'mydb'