What is Version Control? A User-Friendly Guide

What is Version Control? You may have heard your developers talking about it. It’s powerful stuff and a technical-sounding term, but the ideas are simple. Here’s a quick guide to what it is and why it’s so useful.

As the name suggests, Version Control (also known as revision control, source control or source code management) is the software development practice by which changes to a base set of files are managed and monitored. All digital applications and websites are built out of collections of files and directories.

There are about 1835 files in a base WordPress 5.2.1 installation. We’re at 6.5.4 now (June 2024) and the number of files will only have increased (software projects rarely shrink). WordPress is far from the most complex system out there. Human memory is a remarkable thing; we’ve seen individual developers manage code-bases that size. But, add another person working on the project and keeping track of modifications becomes impossible.

In short, if you’re doing anything beyond ‘colouring in’ an existing template and your development team isn’t using some kind of Version Control, you should be alarmed.

But What is Version Control?

Version Control is software which runs alongside your developer’s code – meta-software if you like. The software maintains a database (called a repository) recording code and changes to it. A modern IDE will display those changes in real time.

Periodically, the developer can ‘commit’ their changes to the repository. This updates the database and makes those changes available to others working on the project. If there developers have made changes elsewhere, the developer must ‘update’ their code to include those changes. This means that everyone is working, more or less, with an identical code stack.

Any complete version control system will allow users to create ‘branches’. Branches are where developers can make significant changes and test them without affecting the ‘live’ project.

Why Does it Matter?

1. Collaboration: Version control allows multiple developers to work on the same project simultaneously without overwriting each other’s changes. Branching and merging are key features that facilitate collaborative development.
2. History Tracking: Because every change made in a project is tracked and recorded, Version Control maps how the project has evolved. It helps diagnose when bugs were introduced and permits restoring previous versions if necessary. Furthermore, if mistakes are made, it is clear (using the ‘blame’ function) who made it.
3. Backup and Restore: Additionally, Version control systems act as a backup mechanism. If files are lost or corrupted, they can be restored from the repository.
4. Experimentation: Branches allow to experiment with new features or changes without affecting the main codebase. If the experiment is successful, it can be merged into the main branch. If not, it can be discarded without any impact.

The Basics of Version Control

Version control systems (VCS) are divided into three main categories:

1. Local Version Control Systems: These are the simplest systems. A database on your hard disk keeps all changes to files. Because this approach doesn’t support collaboration between multiple developers, it is little used now.
2. Centralised Version Control Systems (CVCS): These systems, like Subversion (SVN), store all versioned files on a single server. Developers check out files, make changes, and commit them back to the server. But he centralised nature of these systems creates a single point of failure. If the server goes down, no one can collaborate.
3. Distributed Version Control Systems (DVCS): Examples include Git, Mercurial, and Bazaar. In a DVCS, each developer has a complete copy of the repository on their local machine. Changes can be committed locally and then pushed to other repositories, enabling robust collaboration and eliminating the single point of failure issue.

Popular Version Control Systems

• Git: By far the most popular DVCS, millions of developers around the world use Git. It is fast, efficient, and supports non-linear development through its powerful branching and merging model. Unsurprisingly, Git is the foundation of many the most popular platforms like GitHub, GitLab, and Bitbucket.
• Subversion (SVN): Once the dominant system, SVN is still popular with many organisations. It is a simple and effective way to manage changes, but is slower and less flexible than Git.
• Mercurial: Another DVCS, Mercurial, is known for its ease of use and scalability. It is particularly popular in academic and research environments.

Best Practices for Using Version Control

Even with version control, matching and merging changes is difficult. To avoid this development teams should:

1. Commit Often: Regular commits make it easier to track progress and identify when issues are introduced.
2. Write Meaningful Commit Messages: Descriptive commit messages help others understand the changes made and why they were necessary.
3. Use Branches: Branches allow you to work on new features or bug fixes in isolation from the main codebase.
4. Regularly Merge and Rebase: Keeping your branches up to date with the main branch reduces conflicts and ensures a smoother integration process.
5. Review and Test: Code reviews and testing are crucial before merging changes into the main branch to maintain code quality and stability.

Conclusion

Version control is fundamental modern software development. Without it, teams cannot collaborate efficiently, maintain a comprehensive history of changes or experiment with new ideas without risk. If your team cannot answer the question “What Version Control do you use?”, you should probably look elsewhere.