Reinventing the Wheel: A Deep Dive into Building a Custom Git-like Version Control System

In the ever-evolving landscape of software development, understanding the bedrock technologies that power our workflows is paramount. While tools like Git have become ubiquitous, their internal mechanisms often remain a 'black box' for many practitioners. Challenging this opacity, Tony Str.net's author embarked on a compelling journey to reinvent the wheel, constructing a custom version control system dubbed 'tvc' – short for Tony's Version Control.The project's foundation rests on a core principle: Git's reliance on hashing. Every file, directory structure, and commit is meticulously represented by SHA-1 hashes. The author, opting for the more modern SHA-256 for their implementation, details how files are hashed and stored within the `.tvc/objects/` directory. This content-addressable approach ensures that identical files are stored only once, optimizing storage efficiency. Furthermore, the system employs compression, adopting the more performant zstd algorithm over Git's zlib, demonstrating a pragmatic approach to optimizing for speed and space.The implementation, written in Rust, systematically tackles key version control functionalities. From recursively reading the working directory and applying ignore rules (akin to `.gitignore`), to generating tree objects that represent the filesystem's state, and finally constructing commit objects containing metadata like the parent commit hash, author, and message – each step is a deliberate reconstruction of Git's core logic. The author highlights the recursive nature of generating tree objects and how unchanged files, identified by their identical hashes, are efficiently referenced without duplication.A particularly insightful aspect of the project is the author's reflection on the 'checkout' process. This involves parsing the custom object formats and reconstructing the file system from the stored data. The challenge, as noted, often lies in robust parsing, leading to a suggestion for future iterations to utilize well-defined serialization formats like YAML or JSON for object representation. This hands-on endeavor not only solidifies the understanding that Git is fundamentally a content-addressable key-value store but also serves as an invaluable educational resource for developers eager to peer behind the curtain of their daily tools.