Backup task fails when MySQL password requires urlencoding

Aegir 0.4-alpha5
Drush 6.x-3.0-alpha1
Provision version that comes with Aegir alpha5
Drupal 6.15 (Aegir running under this version)
Apache 2.2.12 (Ubuntu)
PHP 5.2.10-2ubuntu6.4 with Suhosin-Patch 0.9.7
MySQL 5.1.37-1ubuntu5.1

After setting up a fresh install of Aegir the backup task kept failing when attempted. I tried the backup task against the imported Aegir site itself and an imported Open Atrium 1.0-beta3.2 site, neither site would successfully backup. When running the same backup task via drush on the command line with the --debug option mysqldump reported "Access denied for user....(using password: YES)".

Next I setup a fresh platform (Drupal 6.15) and created a site under that platform. Once verified and installed, I tried to run the backup task against the site. Low and behold the backup task succeeded!

I eventually determined the backup task was failing because the MySQL password I had used for the Aegir and Atrium 1.0-beta3.2 sites contain special characters. The password appears to be urlencoded in the config/vhost.d/ virtualhost config file, but not in the drushrc.php file. Simply modifying the password to be URL encoded in drushrc.php (at top and bottom) did NOT help. However, when I change the users password in MySQL to not contain special characters and set this new password in virtualhost config and drushrc.php the backup task WORKED!

So I'm not exactly sure where the problem lies (provision, drush or something else), but anyone should be able to reproduce the problem by importing a site that contains a mysql password with special characters.

Below is the output of the failed drush backup command with debugging enabled.

aegir@:~$ /var/aegir/drush/drush.php --root='/var/aegir/platforms/hostmaster-0.4-alpha5' provision-backup 'aegir.example.com' --debug

Drush bootstrap phase : _drush_bootstrap_drupal_root() [0.04 sec, 4.82 MB]                                                                                          [bootstrap]
Loading drushrc "/var/aegir/platforms/hostmaster-0.4-alpha5/drushrc.php" into "drupal" scope. [0.04 sec, 4.82 MB]                                        [bootstrap]
Initialized Drupal 6.15 root directory at /var/aegir/platforms/hostmaster-0.4-alpha5 [0.04 sec, 6.02 MB]                                                       [notice]
Found command: provision-backup (commandfile=provision) [0.05 sec, 6.01 MB]                                                                                       [bootstrap]
Initializing drush commandfile: drush_make [0.05 sec, 6.02 MB]                                                                                                              [bootstrap]
Initializing drush commandfile: drush_make_d_o [0.05 sec, 6.02 MB]                                                                                                       [bootstrap]
Initializing drush commandfile: provision_apache [0.05 sec, 6.03 MB]                                                                                                       [bootstrap]
Undefined index:  base_url [0.05 sec, 6.04 MB]                                                                                                                                   [notice]
Initializing drush commandfile: provision_drupal [0.05 sec, 6.04 MB]                                                                                                        [bootstrap]
Initializing drush commandfile: provision_mysql [0.05 sec, 6.04 MB]                                                                                                         [bootstrap]
Undefined index:  db_url [0.05 sec, 6.04 MB]                                                                                                                                      [notice]
Including /var/aegir/.drush/provision/platform/backup.provision.inc [0.05 sec, 6.05 MB]                                                                              [bootstrap]
Including /var/aegir/.drush/provision/db_server/backup.provision.inc [0.05 sec, 6.08 MB]                                                                            [bootstrap]
Drush bootstrap phase : _drush_bootstrap_drupal_site() [0.05 sec, 6.13 MB]                                                                                           [bootstrap]
Initialized Drupal site aegir.example.com at sites/aegir.example.com [0.05 sec, 6.14 MB]                                                                             [notice]
Loading drushrc "/var/aegir/platforms/hostmaster-0.4-alpha5/sites/aegir.example.com/drushrc.php" into "site" scope. [0.05 sec, 6.14 MB]           [bootstrap]
Drush bootstrap phase : _drush_bootstrap_drupal_configuration() [0.06 sec, 6.53 MB]                                                                               [bootstrap]
Generating mysql dump for aegir.example.com. [0.06 sec, 6.54 MB]                                                                                                         [backup]
mysqldump --defaults-file=/dev/fd/3 -rsites/aegir.example.com/database.sql aegir [0.06 sec, 6.54 MB]                                                         [notice]
Undefined variable: indent [0.06 sec, 6.54 MB]                                                                                                                                    [notice]
Executing: mysqldump --defaults-file=/dev/fd/3 -rsites/aegir.example.com/database.sql aegir
  mysqldump: Got error: 1045: Access denied for user 'aegir'@'localhost' (using password: YES) when trying to connect
Could not generate database backup from mysqldump [0.06 sec, 6.55 MB]                                                                                               [error]
An error occurred at function : drush_provision_mysql_pre_provision_backup [0.06 sec, 6.54 MB]                                                                 [error]
Deleted mysql dump from sites directory [0.06 sec, 6.55 MB]                                                                                                                 [message]
Changes for drush_provision_mysql_pre_provision_backup module have been rolled back. [0.06 sec, 6.55 MB]                                                 [rollback]
Command dispatch complete [0.07 sec, 6.51 MB]                                                                                                                                [notice]
Timer 'page' is  0.01 sec. [0.07 sec, 6.51 MB]                                                                                                                                     [timer]
Peak memory usage was 6.92 MB [0.07 sec, 6.51 MB]                                                                                                                          [memory]