Git Merge and Git Rebase are two different methods for integrating changes from one branch into another in Git. They achieve the same goal but in different ways, each with its own implications for the commit history.

Git Merge

Definition:
Git Merge combines changes from one branch into another, creating a new commit that represents the merge.

How It Works:

1. Merge Operation: When you merge a branch (e.g., feature) into another branch (e.g., main), Git creates a new commit on the main branch that includes the changes from both branches.
2. Commit History: The commit history of both branches is preserved, and a new merge commit is added to the main branch.

Example:

# Switch to the main branch
git checkout main

# Merge the feature branch into main
git merge feature

Pros:

• Preserves History: Maintains the full history of changes and branch structure.
• Simple and Safe: Commonly used in collaborative workflows to integrate changes.

Cons:

• Merge Commits: Can clutter the commit history with additional merge commits, making it harder to follow.

Git Rebase

Definition:
Git Rebase moves or "replays" commits from one branch onto another, rewriting commit history to create a linear sequence of commits.

How It Works:

1. Rebase Operation: When you rebase a branch (e.g., feature) onto another branch (e.g., main), Git applies the commits from feature on top of main, effectively creating a linear history.
2. Commit History: The original commits are replaced with new commits, leading to a cleaner, linear commit history.

Example:

# Switch to the feature branch
git checkout feature

# Rebase the feature branch onto main
git rebase main

Pros:

• Clean History: Creates a linear and cleaner commit history without merge commits.
• Easier to Follow: Simplifies the history, making it easier to understand and debug.

Cons:

• History Rewrite: Rewrites commit history, which can be problematic for shared branches. Avoid rebasing public branches that others may be using.
• Complexity: Can be more complex to resolve conflicts compared to merging.

Summary

• Git Merge: Integrates changes and preserves the commit history, creating a merge commit. Useful for preserving the context of the development process.
• Git Rebase: Rewrites commit history to create a linear sequence of commits, making the history cleaner but potentially more complex to manage, especially for shared branches.

Both methods have their use cases, and choosing between them often depends on your workflow preferences and whether you want to preserve the commit history or maintain a cleaner linear history.