silverstripe/silverstripe-framework — pull request #3272 by halkyon (2014-07-08 00:21:17+00:00)
Title: BUG Config::merge_array_low_into_high() ignores falsey values

Specific case: LeftAndMain::$session_keepalive_ping = true cannot be
set to false in config.yml for some cases because the value is ignored
when merge_array_low_into_high() is processing the config arrays.