■ space · the two timelines

■ the answer first

jj records every operation in an op log; jj undo walks back a wrong rebase or reset — git's reflog only rescues commits.

Git-compatible by default storage: one clone, both tools — remotes, forges, CI keep working.

The record says: try it colocated on a side project; not a big-bang migration — it's 0.x, breaking changes ride monthly releases.

THE TWO TAPES

Press operations. The commit tape (git) and the operation tape (jj) record side by side — then try to take the last one back.

the tapes are empty — press an operation.

GIT · the reflog — commits, ~90 days

the reflog has no opinion about the sequence of commands that produced the mess — you pick the reverse command yourself: reset? revert? cherry-pick?

JJ · the op log — every operation

"because everything is recorded, you can undo that mistake you just made with ease" — the README's own line. jj op log · jj undo.

Git's undo story assumes you'll pick the right command. jj's assumes you won't.

WHAT JJ IS, FROM THE RECORD

jj is a Git-compatible VCS: 31,796 GitHub stars, 376 contributors, first release December 2020, a release every single month since

v0.35 (November 2025) through v0.45.1, September 2026, twelve releases, clockwork.

"Git-compatible" is the part people miss: jj uses a Git repo as its default storage — commits and files live in git's format. Clone, remotes, forges and CI keep working.

The "jujutsu vs git" search is the wrong frame: jj is a new interface bolted onto the storage you already trust.

(Meta's Sapling bet the other way — its own storage — and costs more of the git ecosystem.)

CONFLICTS YOU CAN COMMIT

Yes — conflicts are first-class objects, and it matters more than the undo story. Git treats a merge conflict as a temporary working-tree state: resolve now or abort.

jj stores conflicts in history: a conflicted commit can exist, be committed, even pushed.

Resolve later; jj propagates the fix to every descendant — the same mechanism that rebases your stack.

"Stacked PRs with multi-branch rebases are effortless. Conflicts are actual things in the history that you can come back to later. Everything is automatically committed, so I don't lose work from a bad reset/stash pop." — hellcow, Hacker News on jj patterns (236 points)

That last sentence is the one: jj's working copy is itself a commit, amended on every change.

There is no stash, because there is nothing to stash — switching branches carries your work as a commit.

Another switcher at a git-only workplace: "there were 0 issues."

WHAT THE RECORD SAYS AGAINST JJ

Version 0.x, honestly. Twelve monthly releases also means twelve chances a month at breaking changes. The project ships fast and says so.
Bookmarks live outside git. Commits and files use git storage; branch metadata uses jj's own format. Colocated clones bridge the two — one more moving part to understand.
1,262 open issues. Healthy project, real backlog.
The skeptic is still right about something. The most-upvoted reservation in that HN thread: "I've read about jj many times now but I'm still confused as to what problem it actually solves." If your git workflow is one branch and an occasional merge, the operation log will not change your week. The gains arrive with stacked work, conflicted histories, and undo-heavy days.

SHOULD YOU SWITCH?

The verdict, and the honesty line: I've read the record, not run it.

Every number and quote here comes from the repository, its README and the Hacker News thread — not my terminal.

What the record supports: try jj colocated on a side project — one clone, both tools, zero migration. Git knowledge transfers; teams adopt per-person, since jj pushes ordinary git commits.

What it doesn't: a big-bang migration of an established team, or trusting a 0.x tool with release-critical automation before a pin-and-soak period.

The undo gap is real, the design coherent, interoperability removes the excuse — leaving habit.

Would you trade a weekend of muscle memory for an undo log covering the tool itself?

And honestly — when did you last lose work to a reset? Did the reflog get everything?

■ honest stamp I've read the record, not run it. Tested on: the public record — jj v0.35 → v0.45.1 · git 2.4x reflog. Recorded 2026-09-29, refreshed 2026-10-04. Stars, contributors, release cadence, the bookmark caveat, both HN quotes and the README line come from the repository, its README and the linked public thread. The two tapes above are a design diagram, not a bench — they illustrate what each log records, no timings claimed.

end of the two timelines · nothing fetched · everything local