Yeah totally right. I just don't know enough about git to figure it out. But a sibling commenter helped a lot.

And yeah perf probably doesn't matter much. But, like, running my approach on the Rust compile repo takes at least minute on my beefly (if a little dated) machine. But lukasgelbmann's approach only takes about 11 seconds. That's a big improvement.

Yeah though, perf here may not matter much. It's just an example use of bttf that is less than instant. (And it's not really bttf. It's my examples access pattern of git.)