Why can git push fail non-fast forward following git pull?

Question

I got this error and now I'm scared.

$ git pull
Already up-to-date.
$ git push
To git@github.com:Unroll-Me/unrollme_thumbnail_generator.git
 ! [rejected]        master -> master (non-fast-forward)

Answer 1

Perhaps you are not on branch master? git pull only merges the current branch.

Try

git checkout master
git pull origin master
git push