How to Migrate from SVN to Git Without Losing History

Migrating from Subversion (SVN) to Git can seem daunting, but it’s a rewarding shift that brings better branching, speed, and a modern development workflow. In this guide, you’ll learn how to transition smoothly—whether you’re working on a legacy enterprise system or an open-source project.

Why Migrate from SVN to Git?

Subversion has served many teams well, but Git offers:

• Decentralized workflows
• Fast branching and merging
• Better performance
• Distributed collaboration

Git has become the industry standard, and migrating allows you to adopt modern CI/CD pipelines and work seamlessly with platforms like GitHub and GitLab.

🚧 Before You Begin

Ensure you have:

• The latest version of Git installed
• The svn2git tool (or git svn)
• A clean SVN repository
• Backup of your SVN repo

On macOS:

      brew install git svn
brew install svn2git
    

On Ubuntu/Debian:

      sudo apt install git git-svn
    

Note: If your SVN repository uses custom layouts or has a lot of branches/tags, test in a staging area first.

🗺️ Step-by-Step Migration

Step 1: Understand Your SVN Layout

SVN repositories can vary. Common structure:

      /trunk
/branches
/tags
    

But some may have /project/trunk, etc. Knowing the structure is critical.

Step 2: Create a Local Git Repo

Create a clean directory and navigate into it:

      mkdir my-git-repo && cd my-git-repo
    

Step 3: Clone Using git svn (if not using svn2git)

      git svn clone https://svn.example.com/repo --trunk=trunk --branches=branches --tags=tags --authors-file=authors.txt
    

If using a non-standard layout:

      git svn clone https://svn.example.com/project --trunk=src/trunk --branches=src/branches --tags=src/tags --authors-file=authors.txt
    

📄 Sample authors.txt

      jdoe = John Doe <john@example.com>
asmith = Alice Smith <alice@example.com>
    

Step 4: Or Use svn2git (Easier for Standard Layouts)

      svn2git https://svn.example.com/repo   --authors ~/authors.txt   --trunk trunk   --branches branches   --tags tags
    

Step 5: Clean Up Tags and Branches

SVN tags are often imported as branches. Convert them:

      git for-each-ref refs/remotes/tags | while read ref; do
  tag=$(basename "$ref")
  git tag "$tag" "$ref"
  git branch -D -r "tags/$tag"
done
    

Step 6: Push to a Remote Git Repository

      git remote add origin https://github.com/youruser/new-repo.git
git push -u origin --all
git push origin --tags
    

🧼 Optional: Repository Cleanups

Remove SVN metadata:

      rm -rf .git/svn
git gc --prune=now
    

Rewrite long commit messages, squash history, or restructure using:

      git rebase -i
    

⚠️ Common Pitfalls

• Author mapping errors: Ensure authors.txt is accurate.
• Large repos: Split them if necessary.
• Missing tags: Check branch/tag naming conventions in SVN.

🔄 Migrating a Team Workflow

SVN uses centralized commits; Git doesn’t. You’ll need to adapt:

• Teach contributors to fork and use pull requests
• Protect branches (e.g., main, release)
• Establish Git workflows: Git Flow, trunk-based, or GitHub Flow

📊 Useful Tools

• svn2git
• git-svn
• SubGit (commercial)

✅ Final Checklist

• All branches and tags migrated?
• Author map complete?
• History preserved?
• Clean repo structure?
• Git remote set up?

🚀 Wrapping Up

Migrating from SVN to Git is a one-time investment that unlocks better collaboration, workflows, and tooling. Plan carefully, test often, and don’t be afraid to start with a staging repo to refine your process.

Happy Git-ing!