Since the 1.19pre2 I've some errors as for instance :
In fact it's into an action with a %1 parameter which is set to ''.
For instance to reproduce :
Code
<action name="action_one">
action_two('');
</action>
<action name="action_two">
if(%1 != '',
...
);
</action>
%1 seems to be "null"
Works only with :