pre-push hook does not get input on non-fast-forward pushes

Hi,

I noticed that without an additional --force the pre-push hook does not
get any input on stdin if a push would result in non-fast-forward
uploads. This is not a problem per se (although I don't get the
rationale) but it is undocumented and the latter left me puzzled.

(Please keep me in CC since I am not subscribed, thanks)

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner