Both git pull and git fetch are Git commands used to update the local copy of a repository from a remote source. However, they are used in different contexts and have different effects on the local repository. Understanding the difference between these two commands is crucial for effective version control and collaboration in Git.

Git Fetch

git fetch is a command that tells your local git to retrieve the latest meta-data info from the original (yet doesn’t do any file transferring. It’s more like just checking to see if there are any changes available). Here's what happens when you execute git fetch:

• Updates Local Remote-tracking Branches: git fetch downloads new data from a remote repository — including any branches and tags — but it does not merge any of this new data into your working branches. Remote-tracking branches (like origin/main or origin/feature-branch) are updated.
• Safety: git fetch is a safe command in that it brings the remote changes locally but does not alter your working directory or current branch. This allows you to review changes before integrating them into your copy.

Git Pull

git pull, in contrast, is used when you want to update your current HEAD branch with the latest changes from the remote server. This command is essentially a combination of git fetch followed by git merge, meaning it not only fetches updates but also directly attempts to merge them into the branch you are currently working on. Here’s how it behaves:

• Fetch and Merge: git pull will fetch the remote copy of the current branch and immediately attempt to merge it into the local copy. This merge can be fast-forward or may require a commit if there are diverging changes.
• Automatic Merge Commit: If there are changes in the remote branch that are not in your current branch, git pull will attempt to merge automatically and may create a new merge commit in the process.
• Potential for Merge Conflicts: If the local changes that have not been pushed are conflicting with the changes fetched from the remote, git pull will stop to allow you to resolve the conflicts manually.

Practical Use

• Use git fetch to see if there are changes on the remote server with which you might want to update your local branches.
• Use git pull when you are ready to integrate these remote changes into your current branch.

Summary

git fetch is a safer command as it helps you to see the changes before actually integrating them. It’s particularly useful to update the representation of a remote branch in a local environment without merging those changes into your own branches.

git pull is more aggressive. It is convenient for a quick update of your current branch with the remote repository's version. However, you should be careful with git pull if you have local changes that might be overwritten by merge conflicts.

Understanding these differences helps you manage your branches and project history more effectively, avoiding unnecessary merge conflicts and keeping your project history clean and navigable.