Managing Merge Conflicts

The most common cause of merge conflicts happens when another user changes the same file that you just modified. It can happen during pull from a remote repository (or when merging branches).

  1. If you know for sure what file version you want to keep:
  • keep the remote file: git checkout --theirs conflicted_file.txt
  • keep the local file: git checkout --ours conflicted_file.txt

=> You still have to git add and git commit after this

  1. If you do not know why there is a conflict: Dig into the files, looking for:
<<<<<<< HEAD
local version (ours)
=======
remote version (theirs)
>>>>>>> [remote version (commit#)]

=> You still have to git add and git commit after this

During this process, if you want to roll back to the situation before you started the merge: git merge --abort

NOTE: By doing a pull before committing, you can avoid a lot of git conflicts. Your git workflow should therefore be:

  1. git add
  2. git pull
  3. commit -m "descriptive message"
  4. git pull
  5. git push

Example

Continuing with the dessert example we used in the first part of this tutorial, we now have on our local machine

Branches

adapted from https://www.atlassian.com/git/tutorials/git-merge

adapted from https://www.atlassian.com/git/tutorials/git-merge

What are branches? Well in fact nothing new, as the master is a branch. A branch represents an independent line of development, parallel to the master (branch).

Why should I use branches? For 2 main reasons:

  • We want the master to only keep a version of the code that is working
  • We want to version the code we are developing to add/test new features (for now we mostly talk about feature branch) in our script without altering the version on the master.

Working with branches

Creating and using a branch

Few commands to deal with branches:

  • git branch Will list the existing branches
  • git branch myBranchName Will create a new branch with the name myBranchName
  • git checkout myBranchName Will switch to the branch myBranchName

In a rush? create a new branch and switch to it directly:

git checkout -b branchName

Want to switch back to master?

git checkout master

=> Once you have switched to your branch, all the rest of the git workflow stays the same (git add, commit, pull, push)

Creating and using a branch

Done with your branch? Want to merge your new - ready for prime time - script to the master?

  1. Switch back to the master: git checkout master
  2. Get the latest version of the master: git pull origin master
  3. Merge the branch: git merge myBranchName
  4. Delete the branch: git branch -d myBranchName

Next Session

git using RStudio

References