Forging Ahead

Steve is back to talk JJ (Jujutsu version control) and the related product, ChangeSet, that he works on at East River Source Control. Kris and Steve trace why the GitHub monoculture is finally cracking, what JJ does that Git can't, and Steve's hypothesis that AI agents are pushing companies toward monorepos. Then the pair discuss the Opus 4.7 regression debate, the shift from "always use the frontier model" to using LLMs as one tool among many, and a quick discussion of the Tim Cook to John Ternus handoff at Apple.

We've got supporter content, of course! This week that includes Steve's broader thesis that it's easier to scale a big tool down than scale a small one up, why GitHub's pull request model warped how people use Git, auto-rebase and conflicts as first-class citizens in JJ, AI subsidies, and a Bun being ported to Rust. Not a supporter yet? Fix that today by heading over to https://fallthrough.fm/subscribe where you'll get not only extra content but also higher quality audio. Sign up today!

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Thanks for tuning in and happy listening!

Show Notes:

• JJ

Table of Contents:

• Prologue (00:00:00)
• Chapter 1: Episode 70, New Branding, and Catching Up (00:01:14)
• Chapter 2: What is JJ (Jujutsu) and Why It Exists (00:03:43)
• Chapter 3: Change IDs, Tangled, and the Federated Forge Wave (00:08:59)
• Chapter 4: Healthy Diversity After the GitHub Monoculture (00:14:33)
• Chapter 5: Scaling Big Tools Down: Bazel, Buck, Kubernetes, Symfony [Extended] (00:18:03)
• Chapter 6: JJ Is Simpler AND More Powerful: No Index, No Stash (00:18:10)
• Chapter 7: The JJ Workflow: Snapshots, Watchman, and JJ Undo (00:26:06)
• Chapter 8: GitHub Warped Git: Why Patches and Gerrit Are Better [Extended] (00:32:14)
• Chapter 9: Auto-Rebase and Conflicts as First-Class Citizens [Extended] (00:32:14)
• Chapter 10: Getting Started with JJ: Tutorials and Workflows (00:32:29)
• Chapter 11: East River Source Control and ChangeSet: A Forge for Mono-Repo Scale (00:42:28)
• Chapter 12: Why AI Forces Companies into Monorepo Scaling Sooner (00:50:01)
• Chapter 13: AI Subsidies and the Scaling Wall [Extended] (00:54:55)
• Chapter 14: The Opus 4.7 Regression Debate, Goodhart's Law, and Custom Styles (00:55:24)
• Chapter 15: LLMs as Tools, Not Solutions: Local Models, Gemini, and Custom Pipelines (01:04:49)
• Chapter 16: Bun Rewriting in Rust: A Branch That Wasn't Supposed to Be News [Extended] (01:15:48)
• Chapter 17: The Apple CEO Transition: Tim Cook to John Ternus (01:16:08)
• Epilogue (01:24:55)

Hosts

• Kris Brandow - Host
• Steve Klabnik - Host

Socials:

• Website
• Bluesky
• Threads
• X/Twitter
• LinkedIn
• Instagram
• Changelog Zulip
• Gophers Slack

• (00:00) - Prologue
• (01:14) - Chapter 1: Episode 70, New Branding, and Catching Up
• (03:43) - Chapter 2: What is JJ (Jujutsu) and Why It Exists
• (08:59) - Chapter 3: Change IDs, Tangled, and the Federated Forge Wave
• (14:33) - Chapter 4: Healthy Diversity After the GitHub Monoculture
• (18:03) - Chapter 5: Scaling Big Tools Down: Bazel, Buck, Kubernetes, Symfony [Extended]
• (18:10) - Chapter 6: JJ Is Simpler AND More Powerful: No Index, No Stash
• (26:06) - Chapter 7: The JJ Workflow: Snapshots, Watchman, and JJ Undo
• (32:14) - Chapter 8: GitHub Warped Git: Why Patches and Gerrit Are Better [Extended]
• (32:29) - Chapter 10: Getting Started with JJ: Tutorials and Workflows
• (42:28) - Chapter 11: East River Source Control and ChangeSet: A Forge for Mono-Repo Scale
• (50:01) - Chapter 12: Why AI Forces Companies into Monorepo Scaling Sooner
• (54:55) - Chapter 13: AI Subsidies and the Scaling Wall [Extended]
• (55:24) - Chapter 14: The Opus 4.7 Regression Debate, Goodhart's Law, and Custom Styles
• (01:04:49) - Chapter 15: LLMs as Tools, Not Solutions: Local Models, Gemini, and Custom Pipelines
• (01:15:48) - Chapter 16: Bun Rewriting in Rust: A Branch That Wasn't Supposed to Be News [Extended]
• (01:16:08) - Chapter 17: The Apple CEO Transition: Tim Cook to John Ternus
• (01:24:55) - Epilogue