I'm working on a tutorial and the tutorial actually provided a git repository, which one was to fork and work with. When I forked the repository, I only forked the master branch, as I assumed that's the only one I need.

The next assignment is to check out a speficic branch from that repository. And Im not quite sure how to do that.

I know that I can simply create a new repo and fork the whole thing again but that would throw me back to the start and somewhat disrupt the flow.

So what I tried is to add the source repo (provided by tutorial) as a remote (next to my forked repo), check out the branch, push it to my own forked repo and rebase it accordingly.

This didnt work.

I did add the source repo as remote and when I run git remote it is listed there. However, none of the branches are. When I use git branch all I see is my own master branch.

I also tried `git fetch -t source/branch but that didnt work either.

I saw this answer and it's basically what I tried but when I try to checkout I get this error:

# German
# fatal: 'source/branch' ist kein Commit und es kann kein Branch 'branch' aus diesem erstellt werden.

# English
# fatal: 'source/branch' is not a commit and  branch 'branch' could not be created

Is there any way to do this properly without starting from scratch by forking the source repo agian? Could you explain to me why my approach didn't work?

CodePudding user response：

When I use git branch all I see is my own master branch.

Correct, because git branch lists only local branches that you have created,¹ and you have not created any other local branches. But when you say git branch --all you see all the branches. You can then check any of them out locally.

I'll demonstrate (follow along on your machine if you like). I go to https://github.com/BLeeEZ/amperfy (chosen at random!) and make a fork where, making the same mistake you made, I choose to take only the master branch. I then clone my fork to my own computer, using the instructions that GitHub gives me:

% git clone [email protected]:mattneub/amperfy.git
% cd amperfy

Now, still pretending to be you, I realize that I needed all the branches; so I decide to add the original as a second remote. It is usual to call this upstream (not source) so I will do that:

% git remote add upstream https://github.com/BLeeEZ/amperfy

Now I have to fetch in order to get the branches from upstream (perhaps this is the step you forgot? You do not mention it anywhere):

% git fetch --all

Okay, so when I say merely git branch I see only my own master branch, just as you say:

% git branch
* master

But when I say git branch --all, there they all are!

% git branch --all
* master
  remotes/origin/HEAD -> origin/master
  remotes/origin/master
  remotes/upstream/HysteriaPlayer
  remotes/upstream/develop
  remotes/upstream/gapless
  remotes/upstream/gaplessStreamingKit
  remotes/upstream/master
  remotes/upstream/miniPlayerNextButton

So you see, I do have all the branches from upstream, which is my second remote corresponding to your source.

Finally, let's say I want to check out one of these branches locally. I'll check out gapless:

% git switch gapless

Presto, I have created a local gapless branch corresponding to upstream/gapless. I could now, if desired, work with this branch and ultimately push it to my own fork:

% git push origin gapless

---

¹ You might say: So where did master come from? I never "created" it. Well, yes you did. When you git clone, Git kindly saves you a step by checking out the remote's default branch as a local branch, thus creating it for you. You can actually suppress that step when you clone (by saying -n), thus ending up with no local branches at all. That can actually be a very useful thing to do, and I do it quite often.

CodePudding user response：

I've documented how to work with remote branches originated from PR's while using the Forking Strategy and how to commit your local changes back to the original fork branch which also updates the PR. This requires you have write permission on the remote repo. Otherwise, you can only send a PR to the original author.

I'm using BitBucket server.

https://blog.jeremyfiel.com/bitbucket-pull-pr-and-commit-local-changes-remote-forks