How to Fetch and Merge in Git: A Complete Guide

In Git, fetch and merge are essential commands that help you sync your local repository with the latest changes from a remote repository. Understanding how these commands work allows you to keep your work up to date and resolve any conflicts with changes made by collaborators.

This blog post will walk you through the fetch and merge commands, how they differ from pull, and provide best practices for maintaining a clean, updated codebase.

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Understanding Git Fetch and Merge

Let’s first break down what each command does:

• git fetch: Downloads changes from the remote repository to your local Git repository but does not apply them to your working directory. It updates only your remote tracking branches, allowing you to review changes before merging them.
• git merge: Combines changes from one branch into another. You can use merge to incorporate fetched changes from the remote branch into your current branch.

This two-step approach of fetching and then merging is beneficial when you want to inspect the updates before integrating them, offering more control over when and how you merge.

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How to Use git fetch

1. Fetch Changes from the Remote Repository The command to fetch updates from the remote repository is straightforward:

   git fetch

This command checks the remote repository for changes on all branches and updates your local references, allowing you to see what’s new without merging changes into your current branch.

2. Fetch Changes from a Specific Branch If you only want to fetch updates for a specific branch (e.g., main), specify the branch name:

   git fetch origin main

Here:

• origin refers to the default name of your remote repository.
• main is the branch you’re fetching changes from.

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How to View Fetched Changes

Once you’ve fetched the changes, you can use Git commands to inspect them before merging:

• Show Differences: Use the git diff command to compare your branch with the fetched branch. For example:

  git diff origin/main

This shows the changes between your current branch and the fetched main branch from the remote repository.

• Check Fetched Branches: List all remote branches with:

  git branch -r

This allows you to see all remote branches and check which have updates before merging.

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How to Use git merge

Once you’re satisfied with the fetched changes, you can merge them into your current branch.

1. Merge a Remote Branch into Your Current Branch To merge a branch (e.g., main) from the remote repository, use:

   git merge origin/main

This command combines the changes from the fetched origin/main branch into your current branch.

2. Resolve Any Merge Conflicts Occasionally, Git may encounter merge conflicts if the same lines in a file were modified on both branches. If this happens, Git will pause the merge and allow you to manually resolve the conflicts. Here’s how:

• Open the conflicting files in a text editor. Git will mark the conflicting lines, usually like this: <<<<<<< HEAD your changes ======= changes from origin/main >>>>>>> origin/main
• Edit the file to choose the correct version or combine the changes.
• After resolving the conflicts, stage the resolved files with git add: git add <filename>
• Complete the merge by committing the changes: git commit -m "Resolve merge conflicts"

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Using git fetch and merge vs. git pull

You may be wondering why we’re using fetch and merge separately instead of using git pull, which combines both actions in one command. Here’s why:

• git pull: A convenient command that fetches changes and immediately merges them. While it’s quicker, git pull merges changes into your branch right away, which may cause unexpected conflicts.
• git fetch and merge: This approach gives you more control over when to merge, allowing you to review changes before they’re applied.

For projects where you want to review every update carefully, or if you’re working on a team and want to avoid surprise conflicts, the fetch and merge sequence is ideal.

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Summary of Git Fetch and Merge Commands

Command	Purpose
git fetch	Fetches changes from the remote repository without merging them
git fetch origin main	Fetches changes from the main branch of the remote repository
git diff origin/main	Shows the differences between your branch and the fetched branch
git merge origin/main	Merges changes from the fetched main branch into your current branch
git pull	Combines fetch and merge by downloading and merging changes in one command

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Best Practices for Fetching and Merging

1. Fetch Regularly: Keep your local repository updated by fetching frequently, especially if you’re working on a collaborative project. Regular fetches allow you to monitor changes and keep your local branches aligned with the remote.
2. Review Before Merging: Always inspect fetched changes using git diff or git log to understand what you’ll be merging into your branch. This is particularly useful in large projects with frequent updates.
3. Handle Merge Conflicts Promptly: Conflicts are a natural part of collaborative workflows, especially when multiple people work on the same files. Resolve conflicts carefully and avoid overwriting others’ changes.
4. Use pull for Simple Workflows: For small or personal projects, git pull may be faster if you’re the only contributor. It combines fetch and merge in one step, which can save time when conflicts are unlikely.

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Example Workflow Using Fetch and Merge

Let’s go through an example to see fetch and merge in action in a collaborative project.

1. Fetch the Latest Changes

   git fetch origin main

This command fetches any new changes on the main branch of the remote repository, updating your tracking branch (origin/main).

2. Review Changes Before Merging Use git diff to compare the fetched changes with your branch:

   git diff origin/main

This will show you any new additions, deletions, or modifications.

3. Merge the Fetched Changes After reviewing, merge the origin/main changes into your current branch:

   git merge origin/main

If there are conflicts, resolve them manually, stage the resolved files with git add, and then complete the merge with git commit.

4. Continue Working with the Updated Code Now, you have the latest changes integrated, and you’re ready to continue working without worrying about outdated code.

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Conclusion

Using git fetch and git merge together provides a controlled, conflict-aware workflow that is ideal for collaborative environments. By following these steps and best practices, you’ll be able to stay up to date with remote changes while keeping your local work clean and organized. With fetch and merge in your Git toolkit, you’re well-prepared to manage and merge changes efficiently in any project.