[sunshowers]

As a source control expert and jj's number one fan [1], I would count being able to defer merge conflict resolution as a new capability, FWIW. In general I think jj's greater than the sum of its (very good) parts because of how its features work together to create a coherent and pleasant user experience.

[1] the top testimonial on https://jj-vcs.github.io/jj/latest/testimonials/ is mine

[saulrh]

I guess I was thinking in terms of the patches you push up to github. `jj` is a joy to use and it absolutely enables me to implement workflows that I wouldn't even vaguely consider without it helping me; the big one I think of is the one where you work in a merged dir with like six parents and use `jj absorb` to instantly spread your changes out to the different PRs. I've been forced to do that in git. It was a nightmare and took me two days. Not impossible! Just utterly impractical. `jj` takes end results that were theoretically-possible-but-practically-infeasible and makes them usable. Which I suppose counts as a new capability from the UX perspective. :P

[sunshowers]

Absolutely! jj is a real advancement in the state of the art. I think it's the second time in the history of source control where the authors of a new system have spent a long time working on existing systems + deploying them at scale, and have brought their full expertise to bear on the design of the new system.

(The first was BitKeeper, which also was a tremendous achievement.)

[ahartmetz]

Third time? SVN was a big improvement over CVS. CVS was full of UX blunders, kind of like Git compared to something with good UX.

[sunshowers]

Did the Subversion creators have a lot of prior experience working on CVS?

[steveklabnik]

Yes: https://svnbook.red-bean.com/en/1.7/svn.intro.whatis.html#sv...

> In February 2000, they contacted Karl Fogel, the author of Open Source Development with CVS (Coriolis, 1999), and asked if he'd like to work on this new project. Coincidentally, at the time Karl was already discussing a design for a new version control system with his friend Jim Blandy. In 1995, the two had started Cyclic Software, a company providing CVS support contracts, and although they later sold the business, they still used CVS every day at their jobs

You may recognize Jim as one of the authors of Programming Rust.

[sunshowers]

oh neat!

[rob74]

...and don't ask about the first version control tool I had the "pleasure" of using, M$'s Visual SourceSafe o_O

[ahartmetz]

From what I've heard, it was more of a version information disposal system.