Hi, On Sat, Apr 2, 2016 at 5:25 PM, Benjamin Sandeen <benjaminsandeen2016@xxxxxxxxxxxxxxxxxx> wrote: > Today, I managed to create a duplicate branch in a git repository. While > this may not be a bug per se, I do think that it is confusing and some way > of preventing such issues in the future may be helpful. > > I first cloned the repository: > > $ git clone https://github.com/CodeForChicago/superclass.git > > Then, I created a new branch (or so I thought): > > $ git checkout -b lesson_page > > However, this branch has already existed for about 4 weeks, without my > knowledge. I proceeded to do some work on the files it contained, and when > it came time to commit and push, and when I pushed, I got the following > message: The branch existed in the remote repository, but it doesn't exist locally. You never fetched a copy into refs/remotes/origin since you didn't say you were interested, and git will fully allow you to create local branches with the same name as remote branches. > > To https://github.com/CodeForChicago/superclass.git > ! [rejected] lesson_page -> lesson_page (non-fast-forward) > error: failed to push some refs to ' > https://github.com/CodeForChicago/superclass.git' > hint: Updates were rejected because the tip of your current branch is behind > hint: its remote counterpart. Integrate the remote changes (e.g. > hint: 'git pull ...') before pushing again. > hint: See the 'Note about fast-forwards' in 'git push --help' for details. > When you tried to push this branch, it will push into refs/heads/lesson_page on the remote, which already exists. Since it cannot perform a fast-forward update, as your local work isn't based directly on the tip of the remote branch, you either need to merge, rebase, or start from scratch. > Given that I had believed that I had created the branch just a few hours > prior and was the first to attempt to push to it, this error was > consternating. Let me try to explain. You created your own local branch, which happened to share the same name as an already existing branch. Had you know this you could have fetched and checked out that branch. You can view all branches using "git branch -a" or "git ls-remote". > > I may be wrong (I am aware that my understanding of git is limited), but I > believe that the git checkout -b command is simply supposed to create a new > branch and then switch to it (I'm not aware of any subtle behavior that goes > on behind the scenes if the "new" branch that the user is attempting to > create already exists). This is why I said it "may not be a bug per se". > However, I expect most people who use git to expect this command to create a > new branch and then switch to it (this is what most sources online will tell > users to do to create a new branch), and as such, it would be extremely > beneficial if git were to, at the very least, alert the user to the conflict > in some way or another. git checkout -b <branch_name> will create a new branch in your local copy of the repository. Git is distributed. You can do "git checkout --track <branch>" to attempt to create a local branch which tracks the upstream branch, and then git status will provide useful information about the relationship between your local work and the remote work. It could maybe be improved to notice that a remote has a branch with the same name. However, git can support multiple remotes, so determining which remote to care about is difficult. In your case you have a couple of options to fix it. I would suggest at least "git branch --set-upstream-to=origin/<branch_name>" so that git status will give you useful information about the branch relationship. Then you can merge or rebase your work into the branch. The issue is in understanding how git distributes branches, and how it could handle this. I suspect improvements could be made so that it will attempt to warn you when you create a branch that already exists. However, often you do this *intending* to make it track the specific branch so I am not sure how much good a warning would do. Just a message wouldn't really hurt anything, however. Thanks, Jake > > Thanks, > Ben > -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html