Mac setup gotchas

Two Homebrews

This machine has both. Intel wins the PATH:

Prefix	Arch	node
/usr/local	x64, under Rosetta	v23.10.0 ← first on PATH
/opt/homebrew	arm64 (native)	v23.1.0

Anything brewed via the brew on PATH lands in the Intel prefix and runs emulated.

The symptom

Error: Cannot find native binding
Cannot find module '@rolldown/binding-darwin-x64'

Astro 7 ships Vite 8, which uses rolldown. Bun (arm64) installed the arm64 binding; astro runs under x64 Node and looks for the x64 one. Nothing is wrong with the project — CI is fine, since Linux is x64 throughout.

Fixes

Per-command, no setup:

bun --bun run dev     # runs on Bun's own arm64 runtime

Permanent — put native Homebrew first in ~/.zshrc:

export PATH="/opt/homebrew/bin:$PATH"

Then node -p process.arch says arm64 and plain bun run dev / npx work. Caveat: this also changes which brew you get.