branch.<name>.pushremote not working with push.default simple or upstream

Hi, I tried to use the new Git feature to push by default to a different remote you normally pull but I had some problems. I asked in the #git IRC channel and been told it looks like a bug and to report it here.

I have 2 remotes, origin and upstream. origin is my private fork (and I can push to it) while upstream is read-only for me. I have only one branch, 'master' (present in all the remotes), originally tracking origin/master.

I changed branch.master.remote to upstream and set branch.master.pushremote to origin, but when I do I git push I get an error:

$ git push --dry-run --verbose fatal: You are pushing to remote 'origin', which is not the upstream of your current branch 'master', without telling me what to push to update which remote branch.

I'm using push.default 'simple' to stay forward compatible with Git 2.0. In the IRC channel they suggested to try with other push.default settings and I did. 'matching' and 'current' works, but 'simple' and 'upstream' fail with the error message above.

Thank you.