Git Merge

git merge combines the history and changes of one branch into the currently checked-out branch.

git merge branch-name

For example:

git switch main
git merge feature-login

Merge is useful when development work has been completed on a separate branch and needs to become part of another branch.

• Combine feature work
• Combine bug fixes
• Integrate development branches
• Bring completed work into main
• Combine changes from multiple developers

The basic syntax is:

git merge branch-name

The specified branch is merged into the branch that is currently checked out.

The current branch is the target branch of the merge.

git switch main
git merge feature-login

Here, feature-login is merged into main.

main
  |
  A → B

feature-login
      |
      C → D

If you switch to main and merge feature-login, Git combines the histories.

git switch main
git merge feature-login

git switch main
git switch -c feature-login

Now you can develop the feature independently.

git add .
git commit -m "Add login feature"

The feature branch now contains a commit that can later be merged into another branch.

Before merging the feature branch into main, switch to main:

git switch main

Verify the current branch:

git branch --show-current

Now merge the feature branch:

git merge feature-login

Git combines the changes from feature-login into main.

A fast-forward merge can occur when the target branch has not moved forward since the feature branch was created.

A → B → C → D
         ↑
      feature

If main still points to C, Git can move the main pointer forward to D without creating a merge commit.

If the branches have diverged, Git may create a merge commit.

        C → D
       /     \
A → B         M
       \     /
        E → F

The merge commit combines the two development histories.

After merging, use:

git log --oneline --graph --all

This can help you visualize branches and merge commits.

Use:

git status

After a successful merge, Git may show that the working tree is clean if there are no additional changes.

git switch fix-navbar

# Fix the problem
git add .
git commit -m "Fix navbar issue"

git switch main
git merge fix-navbar

The completed bug fix is now integrated into the main branch.

A merge conflict can happen when Git cannot automatically combine changes from the branches.

This commonly happens when different branches modify the same parts of the same file.

git merge feature-login

Git may stop and ask you to resolve the conflicting files.

If a merge conflict occurs, use:

git status

Git will identify files that have unresolved conflicts.

A conflicted file can contain markers such as:

<<<<<<< HEAD
Your current branch changes
=======
Incoming branch changes
>>>>>>> feature-login

These markers help you identify the competing changes.

To resolve a conflict:

1. Open the conflicted file.
2. Review both sets of changes.
3. Remove the conflict markers.
4. Keep the correct final content.
5. Save the file.
6. Stage the resolved file.

git add filename

After resolving and staging all conflicts, complete the merge:

git commit

Git may prepare an appropriate merge commit message automatically.

If you do not want to continue a merge that is currently in progress, you can abort it:

git merge --abort

This attempts to return the repository to the state it had before the merge started.

git switch main

git merge feature-login
git merge feature-dashboard
git merge feature-payment

Each branch is merged separately into the current branch.

The --no-ff option can be used to create a merge commit even when Git could perform a fast-forward merge.

git merge --no-ff feature-login

This can preserve an explicit merge point in the project history.

The --no-commit option can stop before creating the merge commit when a merge commit would otherwise be created.

git merge --no-commit feature-login

This gives you an opportunity to inspect the result before completing the merge commit.

After merging locally, you can push the updated target branch to a remote repository when appropriate.

git switch main
git merge feature-login
git push

The merge itself happens locally; git push sends the resulting commits to the remote repository.

The appropriate workflow depends on the project's collaboration rules.

• Merging into the wrong branch.
• Forgetting to check the current branch.
• Ignoring uncommitted changes before merging.
• Not resolving all merge conflicts.
• Forgetting to stage resolved files.
• Using the wrong source branch.
• Pushing before reviewing the merge result.

git merge feature-login
git merge --no-ff feature-login
git merge --no-commit feature-login
git merge --abort
git status
git add filename
git commit
git log --oneline --graph --all

# Create feature branch
git switch -c feature-login

# Make changes
git add .
git commit -m "Add login feature"

# Switch to main
git switch main

# Merge feature
git merge feature-login

# Check result
git status

# View history
git log --oneline --graph --all

git init

git add .
git commit -m "Initial project"

git switch -c feature-about

# Create about page

git add .
git commit -m "Add about page"

git switch main

git merge feature-about

git log --oneline --graph --all

The feature-about branch is merged into main, bringing the About page changes into the main development line.

The git merge command combines changes from one branch into the current branch.

git switch main
git merge feature-login

Git may perform a fast-forward merge or create a merge commit, depending on the branch history.

If conflicts occur, resolve them, stage the resolved files, and complete the merge. If you do not want to continue, use git merge --abort while the merge is in progress.