I reluctantly stopped using mercurial 10 or so years ago, and reading this brings a little tear to my eye. Mercurial was just about where jj seems to be now. It had revsets. It had just gotten the concept of mutable and immutable commits. It had absorb. It had bookmarks. It never had an "index". The commands had human readable options like I see in this post. It could work with git repositories. Man I miss it.

I'm hesitant to pick jj up in case it ends up losing to git like mercurial did. But it's very tempting.