Branches with remotes

At some point, it is very likely that you have cloned somebody's repository. This means you have an associated remote. The remote is usually called origin because it is where the source originated from.

While working with Git and remotes, you will get some benefits from Git.

We can start with git status and see what we get while working with the remote.

Getting ready

1. We will start by checking out a local branch that tracks a remote branch:

   $ git checkout -b remoteBugFix --track origin/stable-3.2
   Branch remoteBugFix set up to track remote branch stable-3.2 from origin.
   Switched to a new branch 'remoteBugFix'
   

2. The previous command creates and checks out the remoteBugFix branch that will track the origin/stable-3.2 branch. So, for instance, executing git status will automatically show how different your branch is from origin/stable-3.2, and it will also show whether your branch's HEAD can be fast forwarded to the HEAD of the remote branch or not.
3. To provide an example of how the previous step works, we need to do some manual work that will simulate this situation. First, we find a commit:

   $ git log -10 origin/stable-3.2 --oneline
   f839d38 Prepare post 3.2.0 builds
   699900c JGit v3.2.0.201312181205-r
   0ff691c Revert "Fix for core.autocrlf=input resulting in modified fil
   1def0a1 Fix for core.autocrlf=input resulting in modified file and un
   0ce61ca Canonicalize worktree path in BaseRepositoryBuilder if set vi
   be7942f Add missing @since tags for new public methods in Config
   ea04d23 Don't use API exception in RebaseTodoLine
   3a063a0 Merge "Fix aborting rebase with detached head" into stable-3.
   e90438c Fix aborting rebase with detached head
   2e0d178 Add recursive variant of Config.getNames() methods
   

4. The command will list the last 10 commits on the stable-3.2 branch from the remote origin. The --oneline option will show the abbreviated commit hash and the commit subject. For this recipe, we will be using the following commit:

   $ git reset --hard 2e0d178
   HEAD is now at 2e0d178 Add recursive variant of Config.getNames() m
   

5. This will reset the remoteBugFix branch to the 2e0d178 commit hash. We are now ready to continue using the free benefits of Git when we have a remote tracking branch.

We are resetting to a commit that is accessible from the origin/stable-3.2 remote tracking branch; this is done to simulate that we have performed a Git fetch and new commits were downloaded for the origin/stable-3.2 branch.

How to do it…

Here, we will try a few commands that assist you when you have a remote tracking branch:

1. Start by executing git status:

   $ git status
   On branch remoteBugFix
   Your branch is behind 'origin/stable-3.2' by 9 commits, and can be fast-forwarded.
    (use "git pull" to update your local branch)
    nothing to commit, working directory clean
   

   Git is very descriptive when you have a tracking branch and you use git status. As you can see from the message, you can use git pull to update your local branch, which we will try in the next example. Now, we will just perform the merge:

   Tip

   The git pull command is just a git fetch command and then a git merge command with the remote tracking branch.

   $ git merge origin/stable-3.2
   Updating 2e0d178..f839d38
   Fast-forward
    .../org/eclipse/jgit/api/RebaseCommandTest.java | 213 +++++++++++
    .../src/org/eclipse/jgit/api/RebaseCommand.java | 31 +--
    .../jgit/errors/IllegalTodoFileModification.java | 59 ++++++
    .../eclipse/jgit/lib/BaseRepositoryBuilder.java | 2 +-
    .../src/org/eclipse/jgit/lib/Config.java | 2 +.../src/org/eclipse/jgit/lib/RebaseTodoLine.java | 16 +-
    6 files changed, 266 insertions(+), 57 deletions(-)
    create mode 100644 org.eclipse.jgit/src/org/eclipse/jgit/errors/Ille
   

2. From the output, you can see it is a fast-forward merge, as Git predicted in the output of git status.

There's more...

You can also add a remote to an existing branch, which is very handy when you realize that you actually wanted a remote tracking branch but forgot to add the tracking information while creating the branch:

1. Start by creating a local branch at the 2e0d17 commit:

   $ git checkout -b remoteBugFix2 2e0d17
   
   Switched to a new branch 'remoteBugFix2'
   

2. The remoteBugFix2 branch is just a local branch at the moment with no tracking information; to set the tracking branch, we need to use --set-upstream-to or –u as a flag to the git branch command:

   $ git branch --set-upstream-to origin/stable-3.2
   Branch remoteBugFix2 set up to track remote branch stable-3.2 from origin.
   

3. As you can see from the Git output, we are now tracking the stable-3.2 branch from the origin:

   $ git status
   On branch remoteBugFix2
   Your branch is behind 'origin/stable-3.2' by 9 commits, and can be fast-forwarded.
    (use "git pull" to update your local branch)
   
   nothing to commit, working directory clean
   

4. You can see from the Git output that you are nine commits ahead, and you can use git pull to update the branch. Remember that a git pull command is just a git fetch command, and then a git merge command with the upstream branch, which we also call the remote tracking branch:

   $ git pull
   remote: Counting objects: 1657, done
   remote: Finding sources: 100% (102/102)
   remote: Total 102 (delta 32), reused 98 (delta 32)
   Receiving objects: 100% (102/102), 65.44 KiB | 0 bytes/s, done.
   Resolving deltas: 100% (32/32), completed with 19 local objects.
   From https://git.eclipse.org/r/jgit/jgit
    25fe20b..50a830f master -> origin/master
   First, rewinding head to replay your work on top of it...
   Fast-forwarded remoteBugFix2 to f839d383e6fbbda26729db7fd57fc917fa47db44.
   

5. From the output, you can see the branch has been fast forwarded to the f839d383e6fbbda26729db7fd57fc917fa47db44 commit hash, which is equivalent to origin/stable-3.2. You can verify this with git log:

   $ git log -1 origin/stable-3.2 --format=format:%H
   f839d383e6fbbda26729db7fd57fc917fa47db44