Git merge hotfix branch into feature branch

Let’s say we have the following situation in Git:

1. A created repository:

   mkdir GitTest2
   cd GitTest2
   git init
   

2. Some modifications in the master take place and get committed:

   echo "On Master" > file
   git commit -a -m "Initial commit"
   

3. Feature1 branched off master and some work is done:

   git branch feature1
   git checkout feature1
   echo "Feature1" > featureFile
   git commit -a -m "Commit for feature1"
   

4. Meanwhile, a bug is discovered in the master-code and a hotfix-branch is established:

   git checkout master
   git branch hotfix1
   git checkout hotfix1
   

5. The bug is fixed in the hotfix branch and merged back into the master (perhaps after a pull request/code review):

   echo "Bugfix" > bugfixFile
   git commit -a -m "Bugfix Commit"
   git checkout master
   git merge --no-ff hotfix1
   

6. Development on feature1 continues:

   git checkout feature1
   

Say I need the hotfix in my feature branch, maybe because the bug also occurs there. How can I achieve this without duplicating the commits into my feature branch?

I want to prevent to get two new commits on my feature branch which have no relation to the feature implementation. This especially seems important for me if I use pull requests: All these commits will also be included in the pull request and have to be reviewed although this has already been done (as the hotfix is already in the master).

I can not do a git merge master --ff-only: "fatal: Not possible to fast-forward, aborting.", but I am not sure if this helped me.

How do we merge the master branch into the feature branch? Easy:

git checkout feature1
git merge master

There is no point in forcing a fast forward merge here, as it cannot be done. You committed both into the feature branch and the master branch. Fast forward is impossible now.

Have a look at GitFlow. It is a branching model for git that can be followed, and you unconsciously already did. It also is an extension to Git which adds some commands for the new workflow steps that do things automatically which you would otherwise need to do manually.

So what did you do right in your workflow? You have two branches to work with, your feature1 branch is basically the "develop" branch in the GitFlow model.

You created a hotfix branch from master and merged it back. And now you are stuck.

The GitFlow model asks you to merge the hotfix also to the development branch, which is "feature1" in your case.

So the real answer would be:

git checkout feature1
git merge --no-ff hotfix1

This adds all the changes that were made inside the hotfix to the feature branch, but only those changes. They might conflict with other development changes in the branch, but they will not conflict with the master branch should you merge the feature branch back to master eventually.

Be very careful with rebasing. Only rebase if the changes you did stayed local to your repository, e.g. you did not push any branches to some other repository. Rebasing is a great tool for you to arrange your local commits into a useful order before pushing it out into the world, but rebasing afterwards will mess up things for the git beginners like you.

You should be able to rebase your branch on master:

git checkout feature1
git rebase master

Manage all conflicts that arise. When you get to the commits with the bugfixes (already in master), Git will say that there were no changes and that maybe they were already applied. You then continue the rebase (while skipping the commits already in master) with

git rebase --skip

If you perform a git log on your feature branch, you'll see the bugfix commit appear only once, and in the master portion.

For a more detailed discussion, take a look at the Git book documentation on git rebase (https://git-scm.com/docs/git-rebase) which cover this exact use case.

================ Edit for additional context ====================

This answer was provided specifically for the question asked by @theomega, taking his particular situation into account. Note this part:

I want to prevent [...] commits on my feature branch which have no relation to the feature implementation.

Rebasing his private branch on master is exactly what will yield that result. In contrast, merging master into his branch would precisely do what he specifically does not want to happen: adding a commit that is not related to the feature implementation he is working on via his branch.

To address the users that read the question title, skip over the actual content and context of the question, and then only read the top answer blindly assuming it will always apply to their (different) use case, allow me to elaborate:

• only rebase private branches (i.e. that only exist in your local repository and haven't been shared with others). Rebasing shared branches would "break" the copies other people may have.
• if you want to integrate changes from a branch (whether it's master or another branch) into a branch that is public (e.g. you've pushed the branch to open a pull request, but there are now conflicts with master, and you need to update your branch to resolve those conflicts) you'll need to merge them in (e.g. with git merge master as in @Sven's answer).
• you can also merge branches into your local private branches if that's your preference, but be aware that it will result in "foreign" commits in your branch.

Finally, if you're unhappy with the fact that this answer is not the best fit for your situation even though it was for @theomega, adding a comment below won't be particularly helpful: I don't control which answer is selected, only @theomega does.

git merge

you can follow below steps

1. merge origin/master branch to feature branch

# step1: change branch to master, and pull to update all commits
$ git checkout master
$ git pull

# step2: change branch to target, and pull to update commits
$ git checkout feature
$ git pull

# step3: merge master to feature(⚠️ current is feature branch)
$ git merge master

2. merge feature branch to origin/master branch

origin/master is the remote master branch, while master is the local master branch

$ git checkout master
$ git pull origin/master

$ git merge feature
$ git push origin/master

Based on this article, you should:

• create new branch which is based upon new version of master

  git branch -b newmaster

• merge your old feature branch into new one

  git checkout newmaster

• resolve conflict on new feature branch

The first two commands can be combined to git checkout -b newmaster.

This way your history stays clear because you don't need back merges. And you don't need to be so super cautious since you don't need to do a Git rebase.