git push rejected

First use

git pull https://github.com/username/repository master

and then try

git push -u origin master

First, attempt to pull from the same refspec that you are trying to push to.

If this does not work, you can force a git push by using git push -f <repo> <refspec>, but use caution: this method can cause references to be deleted on the remote repository.

When doing a push, try specifying the refspec for the upstream master:

git push upstream upstreammaster:master

Jarret Hardie is correct. Or, first merge your changes back into master and then try the push. By default, git push pushes all branches that have names that match on the remote -- and no others. So those are your two choices -- either specify it explicitly like Jarret said or merge back to a common branch and then push.

There's been talk about this on the Git mail list and it's clear that this behavior is not about to change anytime soon -- many developers rely on this behavior in their workflows.

Edit/Clarification

Assuming your upstreammaster branch is ready to push then you could do this:

1. Pull in any changes from the upstream.

   $ git pull upstream master

2. Switch to my local master branch

   $ git checkout master

3. Merge changes in from upstreammaster

   $ git merge upstreammaster

4. Push my changes up

   $ git push upstream

Another thing that you may want to do before pushing is to rebase your changes against upstream/master so that your commits are all together. You can either do that as a separate step between #1 and #2 above (git rebase upstream/master) or you can do it as part of your pull (git pull --rebase upstream master)