A note about git merge

Stefan Marx
November 2, 2023 | 2 minutes

Overview:

git merge is a command that lets you take the independent lines of development created by git branch and integrate them into a single branch. When you merge two branches, Git tries to automatically join the diverged paths of development.

For the purpose of this explanation:

• The branch you want to merge from is called the source branch.
• The branch you want to merge into is called the target branch.

Steps to merge your development branch into the main branch:

1. Switch to the Target Branch: Before you can merge your development branch into the main branch, you should be on the main branch.

   git checkout main
   

2. Merge the Source Branch: Once you’re on the main branch, you can merge your development branch into it.

   git merge development
   

3. Handle Merge Conflicts (If Any): If there are no conflicting changes, the merge will be successful. However, if there are conflicts, you’ll see a message indicating this. You’ll then need to resolve those conflicts manually.

   • Open the files with conflicts. Conflicts will be marked with markers such as <<<<<<<, =======, and >>>>>>>.
   • Edit the file to resolve the conflict. Remove the conflict markers once done.
   • After resolving conflicts, commit the changes:

     git add filename
     git commit -m "Resolved merge conflicts"
     

4. Push the Changes: If you’re working with a remote repository (e.g., on GitHub, GitLab, etc.), you’ll want to push your merged changes to update the remote main branch.

   git push origin main
   

Fast-forward Merges:

When the main branch hasn’t progressed since you branched off, Git performs a “fast-forward” merge. This means the main branch pointer is just moved forward to point to the same commit as the development branch.

Merge Commits:

If the main branch has progressed since you branched off, Git will create a new commit to capture the merge. This new commit has two parent commits, which signifies that it has merged the histories of the two branches.

Conclusion:

Merging is a fundamental part of working with Git and collaborating with others. Over time, you may also encounter other merge strategies or options (like `rebase`), but the basics presented here will help you get started with standard merging processes.