I did it once, I was indeed really nice, and the discussion that we did after was very cool. I put in the last slide of the presentation some questions for my colleagues answer based on the Git data model, e.g.: "Can we move a commit to another branch?" or "What guarantees that we don't have cycles in the commit graph". I was really satisfying that people came out thinking Git, not only using it!
This is precisely why it enrages me when all HN discussion about Git devolves to the same stuff about how it's complex and this and that.
A technical person who has general sense about basic data structures (Leetcode nonsense not needed) can be taught Git in under 2 hours and they will retain this knowledge forever.
If you can't invest that little time to learning a tool you will use everyday and instead will spend hours Googling and blindly copy-pasting Git commands, that's on you, not on Git.
Git is only a directed graph with the adjacencies stored as hashes. Everything else is just tooling around that data structure. No problem using Google to find the commands (the Git CLI is very inconsistent...) but if you know what you want to do with that data structure you can find precisely the commands for that.
Even though SHA-1 collision were achieved, they are impractical and we can make the assumption that "if two objects has the same hash, they are the same".
To have a cycle, both commits involved would need to have the hash of the other, which is impossible: the hash of a commit is based on its content, its content contains the hash of its parent.
We could only have a cycle here if we create two commits created after two arbitrary hashes.
