STRATEGYOther
Tech writer Simon Willison and HashiCorp founder Mitchell Hashimoto on coding agents and language portability. Bun migrated its codebase from Zig to Rust in two weeks.
The "rewrites considered harmful" era (Joel Spolsky) is over. Coding agents made framework and language choice reversible.
Framework conservatism premium collapses. Experimentation premium rises. Bun migrated Zig to Rust in two weeks. That's the proof. The vendor that ships the best coding-agent integration wins the next decade of frameworks.
Stop treating language migration as a multi-year project. Budget it as a quarter. Architectural reversibility is the new competitive primitive. Audit your stack for portability.
⚡ Why this matters
- "Rewrites considered harmful" (Joel Spolsky) era is over.
- Programming languages and frameworks just stopped being sticky.
- Stop treating language migration as a multi-year project.
🔍 What happened
- May 16, 2026. Simon Willison + Mitchell Hashimoto on coding-agent-driven language portability.
- Bun migration from Zig to Rust in 2 weeks via coding agents.
- "Rust is expendable. Useful until it's not."
- Coding-agent-driven React Native rewrite anecdote.
- HashiCorp Ghostty noted as another case.
- Framework conservatism premium collapses. Reversibility becomes the new architectural primitive.
💬 Smart takes
- Simon Willison: "Not so locked in any more."
- Mitchell Hashimoto: framework choice is now a 2-week decision, not a 2-year one.
- Skeptic: Bun is a small codebase. React Native rewrite was opinionated. Whether this generalizes to 10M+ LOC legacy enterprise codebases is unproven. Migration cost isn't just code translation. It's tooling, testing, deployment, team training.
🧭 Where this goes
- The "rewrites considered harmful" era ends officially. Articles cite the death of Spolsky's framing within 90 days.
- Architectural decisions get reviewable on 6-month cycles instead of multi-year commitments.
- Programming language ecosystems compete on coding-agent integration quality, not historical inertia.
- First major enterprise (Stripe, Shopify, Cloudflare scale) ships a public Rust or Go migration anecdote within 12 months.
🎯 Implication
- For engineering leaders: stop budgeting language migration as a multi-year project. Budget it as a quarter.
- For CTOs: architectural reversibility is now a competitive primitive. Audit your stack for portability.