non-numeric value encountered @ sfYamlInline.php

[xerc]

https://github.com/propelorm/Propel/blob/3f7a284906ce3e402bcb101938270842fdad71fa/runtime/lib/parser/yaml/sfYamlInline.php#L130 return (integer) $v + (integer) $w;

[jestep]

Following, would prefer not to patch my own installations to have them overwritten on a future update.