[SR-Users] $du gets set automatically before branch_route

[Alex Hermann]

Hello,


while trying to upgrade from 1.5 to 3.1 i noticed that between t_relay() and  
branch_route, $du gets automatically set to $ru if it has not been set before. 

This is a change from 1.5 i could not find documentation for, so it might have 
been unintened.

Can someone enlighten me on the purpose of this change and if there is a way 
to determine if $du is (was) unset other than comparing $ru to $du, wich seems 
a bit inefficient?

Is it even guaranteed that $du gets set to $ru in every possible scenario?
-- 
Alex Hermann