Building a Custom Version Control System to Understand Git Internals
By
TonyStr
4mo ago· 9 min readen
100/100
Golden Brown
Bagelometer↗
Slow-proofed and worth the wait. Worth its weight in flour.
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Summary
The article details the author's personal journey of building their own version control system to understand how Git works internally. It explains the core concepts of Git including SHA-1 hashing, object storage (blobs, trees, commits), how diffs are generated, and the structure of the .git directory. The author shares their implementation approach and insights gained from reverse-engineering Git's architecture.
Key quotes
· 5 pulledVersion control used to be a black box for me; I had no idea how files were stored, how diffs were generated or how commits were structured.
Everything in git is based around hashes, specifically SHA-1 hashes. When you commit a file, git hashes the file and stores it in .git/objects/.
Since I love reinventing the wheel, why not take a stab at git?
Then, to be able to find that file again, git makes a 'tree' object (a list of files and subdirectories and their corresponding hashes), hashes it, and stores that in .git/objects/ as well.
Then it makes a commit object which contains the tree hash, author information, commit message, and parent commit(s).
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