deployment - git deploy: force branch switch when everything is up-to-date -

i'm deploying branches on test machine

git push branchname 

on remote test machine there bare repo post-receive hook checkout live:

checkout -f $branchname  

always on same web directory

everything works fine except don't know how switch branch on remote. if remote repo on branch dev1 , git push dev2, if there no changes in dev2, git "everything up-to-date" , nothing happen.

i found solution force git run post-receive hook, if "up-to-date"

but seems me involves "dummy" commit each time want switch branch. other solution?