Git and Git Conflict

Refresher: How does git work?

A typical sequence of events in a developer's day, they:

1. Will make changes to code on their local repo;
2. add the changes to "staging";
3. commit the changes to save a "snapshot" of the project;
4. push the changes to a Remote Repo (i.e. GitHub) when the changes are ready to be shared or deployed.
   • You must pull any new changes from the Remote Repo before you can push. This is when dreaded merge conflicts need to be handled.
   • At any point during development, you can view the status of your repo to find helpful information of the status of your project

A Diagram: How Git flows work

What Are Git Conflicts?

• Git conflicts happens when changes in different source code environment or branches cannot be merged automatically.

  • When local changes are not up to date with remote repositories especially when changes are made on the same line of code.

  OR

  • when a version of a file has been submitted is newer than the version of the file you have started to base your changes on.

• It usually occurs during a pull or merge operation.

$ git pull
> Auto-merging example.md
> CONFLICT (content): Merge conflict in example.md
> Automatic merge failed; fix conflicts and then commit the result

Git Terminologies

Pull

Used to fetch and integrate changes from a remote repository into the current branch. It combines git fetch and git merge. It is mostly used to update a local branch with changes that have been made in the corresponding branch on the remote repository.

Merge

When two branches in Git are merged into one. This will often happen if two developers are submitted code to a project or one developer is submitting code from two machines.

Merge conflict

When two branches edit the same line of code. Git doesn't know which change to keep so it leaves it to the developer to decide when remote code is pulled.

Current Change

The change (relevant to the conflict) that was made on the local repo.

Incoming Change

The change that is incoming from the remote repo.

Common Causes of Git Conflicts?

• Simultaneous changes to the same line of code.

  • When two separate branches have made edits to the same line in a file,

    OR

  • When a file has been deleted in one branch but edited in the other

• Conflicting changes in different branches or location of source code ( e.g. local vs remote).

Resolving Git conflicts

Step 1: Identify Conflicts

• Conflicts occur when Git cannot automatically merge changes from different branches.

• When you encounter a conflict, Git marks the conflicted files and provides information about the conflicting changes.

Step 2: Open Conflicted File

• Open the conflicted file(s) in your code editor. Git adds conflict markers to indicate the conflicting sections.

<<<<<<< HEAD
// Changes from the current branch
=======
// Changes from the incoming branch
>>>>>>> incoming-branch

Resolving Git conflicts continued...

Step 3: Manually Resolve Conflicts

• Review the conflicting sections marked by <<<<<<<, =======, and >>>>>>>.

• Decide which changes to keep or combine the changes.

• Remove the conflict markers and unnecessary lines.

Step 4: Mark as Resolved

git add <conflicted-file>

Resolving Git conflicts continued...

Step 5: Commit Changes

• Complete the merge process by committing the resolved changes.

git commit

Step 6: Verify Resolution

• Check that all conflicts are resolved by running:

• If resolved, the working directory should be clean.

git status

Additional tips

• Git provides merge tools to visually resolve conflicts.
  git mergetool

• f you encounter issues while resolving conflicts, you can abort the merge and start over. Use git merge --abort

• To minimize conflicts, regularly pull changes from the remote repository before making your own changes.

Best practices for Git conflicts

• Regularly pull changes from the remote repository.

• Communicate with team members about ongoing work.

• Create feature branches to isolate changes.

• Resolve conflicts as soon as they arise.

Key Takeaways

• Git conflicts can happen when changes cannot be automatically merged or pulled in.

• Understanding and resolving git conflicts is crucial for smooth collaboration between team members.

• You can also experience git conflicts if you make a change in a remote repository(e.g GitHub repo directly) and then try to pull the changes into your local repository.

• Git conflicts can become messy so you want to apply best practices to your daily workflow.