> What is the value in having history be static?

Because you can trust it. Rewritable history is like maintaining your business ledger on a whiteboard.

> I find that rebase comes in handy as I'm working locally

This idea that local development is a good thing is one of the biggest differences between Git and Fossil.

Git was created to serve the needs of the Linux kernel, where the development effort is not only distributed, but also federated, with islands of development sporadically pushing changes higher up the tree. You see this on Github, with semi-private forks of projects containing changes that never make their way back into the primary project. If that is the sort of project you're working on, Git is the right tool.

Fossil, however, is meant for much more cohesive teams. While it does allow one to go off on a tangent, developing for weeks at a time with no outsiders ever seeing what you're doing, that is not its default mode.

In Fossil's default mode, local checkins are immediately sync'd back to the repo you cloned from, which is typically the official central repo. Fossil allows you to have chains of repos (A clones from B, which cloned from C, which cloned from D...) but a simple 2-level fan-out is much more common.

I think of Fossil as a DVCS with the day-to-day workflow sensibility of Subversion.

The DVCS aspect means you can take your laptop to the mountains with you, code for a week in your tent while your relatives all enjoy the dubious pleasures of nature (the weirdos) then come back home and sync back up with the central repo, your whole change history being grafted back in as if you'd been autosyncing to it the whole time.

The Subversion sensibility means that while working in the office, every checkin normally becomes immediately visible to your team members, as do theirs to you. While this makes some people nervous — particularly those who have only used Git — it has benefits.

I can state those benefits in terms of the [Ten Commandments of Egoless Programming](http://goo.gl/13r3xT), published by Gerald Weinberg way back in 1971 as [The Psychology of Computer Programming](http://goo.gl/NqqGnl). Using his numbering:

1. You will make mistakes, but Git encourages you to hide them in the stash, in private branches, in changed checkin comments (git commit --amend), and in history rewrites. In its default working mode, Fossil pushes every checkin immediately back to the repo you cloned from, where they can be noticed and fixed ASAP. The longer an error goes unnoticed, the greater the damage it can do.

2. You are not your code. Private branches are a symptom of the sort of perfectionism that violates this commandment. You don't want to spend a week going off on a tangent when one of your colleagues could have saved you from wasting your time by seeing the path you started down with your first commit. Fossil has a way to create private branches, but unlike Git, it isn't the default mode. Defaults matter.

4. Don't rewrite other people's code without consultation. You've worked with that guy. You know, the one who runs the whole codebase through indent(1), the one who changes multi_word_function_names to camelCase, the one who "refactors" things endlessly. Git's default mode of working on a private branch, then pushing a bunch of work as a single bolus makes this sort of fiddling worse. Fossil's default autosync mode lets you detect that sort of thing early and nip it in the bud.

6. The only constant in the world is change. So, when a colleague makes a change in trunk that breaks your change-in-development, you want to pull it into your tree ASAP so you can fix up the problem before trying to merge your change in. You don't want to find out a week later when you and your colleague both try to check in week-old private branches, and find that you'll need another day or two of work to fix up the differences.

9. Don't be "the guy in the room." But Git wants you to be that guy. Before you can check a change in with Fossil, it first checks if there are any changes in the repo you cloned from, and makes you either say "fossil up" to pull them into your local repo, or check in on a branch. This encourages you to either test your changes against the tip of trunk before checkin in, or at least publish your changes as a branch so people can see you go haring off in a different direction, and maybe correct your trajectory.

Not all merge conflicts can be detected by the VCS's merge algorithm. Just because your changes merge cleanly into the central code repo doesn't mean you haven't broken the build, or the tests, or... Fossil encourages you to test your change against the tip of the branch you're working on before checking in.

Git amounts to a social regression with respect to Egoless Programming.