The creator of Jujutsu has joined ERSC

Original Article ↗ Hacker News Discussion ↗

A new hire by enterprise-focused source control startup ERSC has drawn attention to Jujutsu (“jj”), a Git-compatible version control system that promises safer, more intuitive workflows with features like universal undo, delayed conflict resolution, and easier commit reshaping. Commenters explore how jj’s Git-backed design lowers switching costs compared to past Git alternatives, while ERSC aims to build a next-generation backend for large monorepos and AI-assisted development rather than a social coding site like GitHub. The thread also surfaces concerns about Google’s contributor license agreement around jj, performance and accessibility issues on ERSC’s animated marketing site, and whether enterprises will embrace a new vendor in such a foundational tooling layer.

Clarifications about ERSC, JJ, and Google

  • JJ (Jujutsu) is an OSS VCS under Apache 2.0 that currently uses Git’s on-disk format and protocol, but with different algorithms and UX.
  • Google does not own copyrights; contributors retain them. The Google CLA grants Google broad license rights but is not a copyright assignment.
  • The GitHub org was moved out from a personal account; Google still controls the org mainly to keep the CLA bot, and holds the “jj” trademark.
  • The new hire left Google to join ERSC but remains a core maintainer of JJ. The maintainers intentionally balance company representation.

ERSC’s Product Direction

  • ERSC positions itself as “next-generation source control for the enterprise,” not a social coding site or straight GitHub competitor.
  • Focus areas: scaling beyond Git’s limits for large monorepos, per-directory ACLs, and organization-wide workflows, especially in “agentic”/LLM-heavy environments.
  • They are building a new backend (likened to Google’s internal systems) with Git ingress/egress for incremental adoption; JJ is the bridge client.
  • Initial go‑to‑market is enterprise-only with sales/onboarding, though individuals won’t be explicitly blocked. CI is “bring your own” at first.

Technical Discussion: JJ vs Git (and Mercurial)

  • JJ offers:
    • First-class conflicts stored in commits, enabling deferred, incremental conflict resolution.
    • A transactional operation log that supports universal undo (for rebases, merges, conflict resolutions, etc.), beyond Git’s reflog.
    • Auto‑rebasing of dependent commits/branches when history changes.
    • A unified model for working copy, index-like behavior, stashes, and conflicts.
  • Copy/rename tracking and other features are under active development.
  • Compared to Mercurial, JJ aims to be faster and gains traction via seamless Git compatibility.

Adoption, UX, and Workflows

  • Fans report drastically easier history editing (reordering, splitting, stacking commits), safer experimentation, and better conflict handling.
  • Some say Git’s core commands plus a GUI already suffice, and they rarely hit problems where JJ’s advantages matter.
  • There is debate over Git’s UX: some see it as fine once you learn VCS theory; others see JJ as a much clearer mental model.
  • JJ can be used unilaterally on Git repos; coworkers need not switch. TUI tools (like jjui) are praised.

Licensing, Governance, and Ownership Concerns

  • Some worry about the Google CLA and trademark creating a “Sword of Damocles” and potential investor red flags.
  • Others argue Apache 2.0 plus distributed copyrights and the ability to fork/rename mitigate real lock‑in risk.

Website Design and Performance Feedback

  • Many praise the new ERSC site’s aesthetics and low latency.
  • Others report severe GPU usage and poor scroll performance on various browsers/OSes; the animated background is cited as the culprit and an accessibility issue.
  • ERSC acknowledges issues, pushes fixes (including removing/toning down animation), and aims to respect reduced‑motion preferences.