Yes, git does use hashes, but git similarly doesn't work in that manner for the ...

fragmede · on May 12, 2015

> Git commits can only point to commits in the past and not future commits.

Not true! With git time-travel, you can refer to a future commits in the commit message. Eg:

    $ git log --oneline HEAD~2..HEAD
    9428c8c I am the child
    cdd3ab5 I am the parent of 9428c8

https://github.com/hundt/git-time-travel

:p

fordh · on May 12, 2015

Ha, that's a clever little tool!

For anyone curious, this uses the same idea as the "guess-and-check" approach spullara mentioned: https://news.ycombinator.com/item?id=953569

It changes the content of the commit (by iterating the hash in the commit message itself) until the hash of the child commit matches. A big part of the trick is that it only looks at a prefix of the hash, so the search space is much smaller than the full SHA1 hash.