That said, I haven't tried this lately, maybe it's gotten more robust over time. But historically, even a bare repo on something like Dropbox has issues.
Sure, but this seams to be more of an issue with Dropbox, not with Git, when I run a database on Dropbox, the same problems occur. I wouldn't trust these to even preserve file attributes correctly, so I would put things into a tarball, before uploading (optionally also encrypting).
Sure, you could view it as Drobox's problem, but the core of it is that git relies on things that Dropbox doesn't support, while jj does not. And so it's usable more safely in more contexts.
No, it avoids doing that (see the link someone shared above). Git actually also rarely overwrites files. The only case I'm aware of are refs, so I think it could happen that a if you modify a branch on two machines and then sync via Dropbox/rsync, one of those changes could get lost.
Ah, you mean to share the repo you are issuing git commands to directly. Yeah I would expect this to cause problems. Surprising to hear that JJ supports this.
This wasn't what I was talking about, I meant that you should create a bare repo and push to it, not that you work directly in a directory in Dropbox.
That said, I haven't tried this lately, maybe it's gotten more robust over time. But historically, even a bare repo on something like Dropbox has issues.