Git merge

Git Merge: Combining Branches

git merge is used to combine changes from one branch into another. This command is essential for integrating work from different branches, such as feature branches or remote branches, into the main project.

1. Basic Git Merge

1.1 Merge Another Branch into Your Current Branch

To merge changes from a different branch into your current branch:

git merge branch-name

🔹 This combines the commits from branch-name into your current branch.
🔹 After merging, if there are no conflicts, Git will create a merge commit.

2. Merge Conflicts

2.1 What are Merge Conflicts?

A merge conflict happens when changes in the two branches are in conflict (i.e., both branches modify the same part of a file). Git will not be able to automatically merge the conflicting changes and will ask you to resolve them manually.

2.2 Resolving Merge Conflicts

1. Identify Conflicts: After running git merge branch-name, Git will show the conflicting files.
2. Open Conflicted Files: Open the files with conflicts. Git marks conflicts with:

   <<<<<<< HEAD
   Your changes
   =======
   Changes from the other branch
   >>>>>>> branch-name
   

3. Resolve Conflicts: Choose which changes to keep (or combine the changes) and delete the conflict markers (<<<<<<<, =======, >>>>>>>).
4. Stage the Resolved Files: After resolving the conflicts, stage the resolved files:

   git add path/to/conflicted-file
   

5. Commit the Merge: Once all conflicts are resolved and staged, commit the merge:

   git commit
   

3. Fast-Forward Merges

If the branch you're merging into is directly behind the branch you're merging from (no divergent commits), Git will perform a fast-forward merge.

• In a fast-forward merge, Git will simply move the pointer of the current branch forward to the latest commit on the merged branch, and no merge commit is created.

Example:

git merge feature-branch

🔹 If there are no other commits on the current branch, this will result in a fast-forward merge.

4. Merging Remote Branches

To merge changes from a remote branch, first fetch the changes, and then merge:

git fetch origin
git merge origin/branch-name

🔹 This pulls in the latest changes from the remote branch and merges them into your current branch.

5. Merge Strategies

Git supports several merge strategies to handle specific cases:

5.1 No Fast-Forward Merge

If you want to force a merge commit even if a fast-forward merge is possible, use:

git merge --no-ff branch-name

🔹 This creates a merge commit even when it could be fast-forwarded.

5.2 Squash Merging

A squash merge combines all commits from the branch into a single commit before merging:

git merge --squash branch-name

🔹 After running the command, you’ll need to commit the squashed changes with git commit.

6. Checking the Merge Status

To check the status of your merge, you can run:

git status

🔹 This will show you if there are any conflicts or if the merge was successful.

7. Summary of git merge Commands

Action	Command
Merge another branch into the current branch	git merge branch-name
Resolve merge conflicts	Open conflicted files, resolve, git add path/to/file, git commit
Force a non-fast-forward merge	git merge --no-ff branch-name
Squash commits before merging	git merge --squash branch-name
Check merge status	git status

8. Conclusion

git merge is a powerful tool to combine work from different branches. While most merges are straightforward, you should be prepared to resolve conflicts if they arise.

🔹 Need further clarification or a specific example? Let me know! 😊