upgrading to (unreleased) 4.3.6 gets sql error on some sites

Out of about 70 sites, we had two with this error:

Exception: "A fatal error was triggered: is not of type String"
#0 /var/aegir/platforms/master-ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Core/DAO.php(1003): CRM_Core_Error::fatal(" is not of type String")
#1 /var/aegir/platforms/master-ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Core/DAO.php(903): CRM_Core_DAO::composeQuery("UPDATE civicrm_line_item cli\nLEFT JOIN civicrm_financial_item cfi ON cli.id ...", (Array:6), TRUE)
#2 /var/aegir/platforms/master-ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Upgrade/Incremental/php/FourThree.php(995): CRM_Core_DAO::executeQuery("UPDATE civicrm_line_item cli\nLEFT JOIN civicrm_financial_item cfi ON cli.id ...", (Array:6))
#3 [internal function](): CRM_Upgrade_Incremental_php_FourThree::updateLineItemData(Object(CRM_Queue_TaskContext), "4.3.6")
#4 /var/aegir/platforms/master-ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Queue/Task.php(79): call_user_func_array((Array:2), (Array:2))
#5 /var/aegir/platforms/master-ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Queue/Runner.php(186): CRM_Queue_Task->run(Object(CRM_Queue_TaskContext))
#6 /var/aegir/platforms/master-ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Queue/Runner.php(148): CRM_Queue_Runner->runNext()
#7 /var/aegir/platforms/master-ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Upgrade/Headless.php(65): CRM_Queue_Runner->runAll()
#8 /home/jamie/projects/ptp/repos/provision_civicrm/civicrm.drush.inc(543): CRM_Upgrade_Headless->run()
#9 [internal function](): drush_civicrm_upgrade_db()
#10 /usr/share/drush/includes/command.inc(134): call_user_func_array("drush_civicrm_upgrade_db", (Array:0))
#11 /usr/share/drush/includes/command.inc(806): _drush_invoke_args("civicrm-upgrade-db", (Array:0), "civicrm")
#12 [internal function](): drush_command()
#13 /usr/share/drush/includes/command.inc(214): call_user_func_array("drush_command", (Array:0))
#14 /usr/share/drush/drush.php(101): drush_dispatch((Array:22))
#15 /usr/share/drush/drush.php(41): drush_main()
#16

{main}

#

It seems to happen if the label is set to NULL in the database.

Here's some sample data from an affected site:

mysql> SELECT cc.id contribution_id, cc.contribution_recur_id,
-> cc.financial_type_id contribution_financial_type,
-> cli.financial_type_id line_financial_type_id,
-> cli.price_field_id, cli.price_field_value_id, cli.label, cli.id line_item_id,
-> cfi.financial_account_id
-> FROM `civicrm_line_item` cli
-> LEFT JOIN civicrm_contribution cc ON cc.id = cli.entity_id
-> LEFT JOIN civicrm_financial_item cfi ON cfi.entity_id = cli.id
-> LEFT JOIN civicrm_price_field cpf ON cpf.id = cli.price_field_id
-> LEFT JOIN civicrm_price_set cps ON cps.id = cpf.price_set_id
-> LEFT JOIN civicrm_price_field_value cpfv ON cpfv.id = cli.price_field_value_id
-> WHERE cfi.entity_table = 'civicrm_line_item'
-> AND cli.entity_table = 'civicrm_contribution'
-> AND cps.is_quick_config = 1 AND cc.contribution_recur_id IS NOT NULL
-> ORDER BY cli.id;
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
5 rows in set (0.11 sec)

mysql> select * from civicrm_line_item where id = 6862;
------------------------------------------------------------------------------------------------------------------------------------------------------------------+

------------------------------------------------------------------------------------------------------------------------------------------------------------------+

------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql>

The fix for the error is trivial. Something like:

— /var/aegir/platforms/ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Upgrade/Incremental/php/FourThree.php 2013-08-28 11:49:04.000000000 -0400
+++ /var/aegir/platforms/master-ourpowerbase-d7-c4.3/sites/all/modules/civicrm/CRM/Upgrade/Incremental/php/FourThree.php 2013-09-04 14:41:41.000000000 -0400
@@ -984,11 +984,11 @@
WHERE cfi.entity_table = 'civicrm_line_item'
AND cli.entity_table = 'civicrm_contribution' AND cli.id IN (" . implode(',', $value). ');';
$params = array(

• 1 => array($financialTrxn[$key]['label'], 'String'),
  + 1 => array(strval($financialTrxn[$key]['label']), 'String'),
  2 => array($financialTrxn[$key]['price_field_id'], 'Integer'),
  3 => array($financialTrxn[$key]['price_field_value_id'], 'Integer'),
  4 => array($financialTrxn[$key]['financial_account_id'], 'Integer'),
• 5 => array($financialTrxn[$key]['label'], 'String'),
  + 5 => array(str($financialTrxn[$key]['label']), 'String'),
  6 => array($dao->contribution_financial_type, 'Integer'),
  );
  CRM_Core_DAO::executeQuery($sql, $params);

But... wanted to see if this was an indicator of something wrong with the data that the code should be checking for. For example, in the data above, it looks like the problem is that the row with a NULL label appears before the row with the non NULL label