special case rendering from filter

I have a special case(does not normally occur) render in a filter.
Because its in a filter, I can't end execution with a 'return' which
would work otherwise. Therefore I get this error:

Can only render or redirect once per action

what version of rails are you using ? In rails 2 and above rendering
from a filter should cause the filter chain to halt. in previous
versions you had to return false from your filter.