VCS/Git/SyncFork
Syncing a fork
The Setup
Before you can sync, you need to add a remote that points to the upstream repository. You may have done this when you originally forked.
It does not update your repository on GitHub.
git remote -v
# List the current remotes
# origin https://github.com/user/repo.git (fetch)
# origin https://github.com/user/repo.git (push)
Add a new remote
git remote add upstream https://github.com/octocat/repo.git
Verify
git remote -v
# Verify new remote
# origin https://github.com/user/repo.git (fetch)
# origin https://github.com/user/repo.git (push)
# upstream https://github.com/octocat/repo.git (fetch)
# upstream https://github.com/octocat/repo.git (push)
Syncing
There are two steps required to sync your repository with the upstream: first you must fetch from the remote, then you must merge the desired branch into your local branch. Fetching
Fetching from the remote repository will bring in its branches and their respective commits. These are stored in your local repository under special branches.
git fetch upstream
# Grab the upstream remote's branches
# remote: Counting objects: 75, done.
# remote: Compressing objects: 100% (53/53), done.
# remote: Total 62 (delta 27), reused 44 (delta 9)
# Unpacking objects: 100% (62/62), done.
# From https://github.com/octocat/repo
# * [new branch] master -> upstream/master
We now have the upstream's master branch stored in a local branch, upstream/master
git branch -va
# List all local and remote-tracking branches
# * master a422352 My local commit
# remotes/origin/HEAD -> origin/master
# remotes/origin/master a422352 My local commit
# remotes/upstream/master 5fdff0f Some upstream commit
Merging
Now that we have fetched the upstream repository, we want to merge its changes into our local branch. This will bring that branch into sync with the upstream, without losing our local changes.
git checkout master
# Check out our local master branch
# Switched to branch 'master'
git merge upstream/master
# Merge upstream's master into our own
# Updating a422352..5fdff0f
# Fast-forward
# README | 9 -------
# README.md | 7 ++++++
# 2 files changed, 7 insertions(+), 9 deletions(-)
# delete mode 100644 README
# create mode 100644 README.md
If your local branch didn't have any unique commits, git will instead perform a "fast-forward":
git merge upstream/master
# Updating 34e91da..16c56ad
# Fast-forward
# README.md | 5 +++--
# 1 file changed, 3 insertions(+), 2 deletions(-)