Dev worktrees

A worktree here is a complete parallel dev environment, not just a second checkout. Each one gets its own branch, node_modules, public domains, port block, SSL certs, Cloudflare DNS records, Metro instance and cloned iOS simulator, so several can run at once without colliding.

Everything is keyed off one git-ignored file at the worktree root: localdomain.js. Read it first whenever you need to know where anything in a checkout lives.

module.exports = {
  main: "local2", api: "local2-api", streamingapi: "local2-streaming-api",
  port: 8090, apiPort: 3010, streamingApiPort: 3011, metroPort: 8091,
};

The index → port scheme

scripts/worktree-create.sh:64 — OFFSET = (INDEX - 1) * 10:

index	domains	web	api	streaming	metro	simulator
1 (base repo, reserved)	local, local-api, local-streaming-api	8080	3000	3001	8081	iPhone 17e RNW
N (2..20)	localN, localN-api, localN-streaming-api	8080+10(N-1)	3000+10(N-1)	3001+10(N-1)	8081+10(N-1)	iPhone 17e RNW <dirname>

Indices are capped at 2..20 and picked at random from the free ones (scripts/worktree-create.sh:50) — deliberately a small reusable pool, because certs are never deleted, so the same handful of domains get renewed rather than newly issued (Let's Encrypt rate-limits new certs, not renewals). Taken indices are discovered by reading every worktrees/*/localdomain.js.

Create

scripts/worktree-create.sh <name> [index]      # run from the base repo root

Does, in order: git worktree add worktrees/<name> -b <name> → writes localdomain.js → npm ci → generators (build:theme, build:markdown, build:programs, build:exercises) → issues/renews certs via lambda/scripts/update_liftosaur_dev_certs.sh (certbot + Cloudflare DNS-01, into ~/.secrets) → points localN*.liftosaur.com A records at this machine's LAN IP via lambda/scripts/change_liftosaur_dev_api.sh.

It does not touch native — pods and the simulator are provisioned later, on demand.

Daily use (all from inside worktrees/<name>)

npm start              # webpack-dev-server on localdomain.port, https from ~/.secrets certs
npm run start:server   # api + streaming api on apiPort / streamingApiPort
npm run worktree:ios   # pods (once) + clone sim (once) + boot + run-ios on the right Metro port
npm run worktree:metro # Metro alone (= rn:start), on this checkout's metroPort
npm test               # fine in a fresh worktree — build:programs already wrote programdata/

npm start is not optional for native work: the RN app's __HOST__ is the web dev server (src/App.native.tsx:30), so images and other assets come from it.

How the port/host actually reaches each layer

Nothing may assume 8080/3000/8081. The plumbing:

• Web + API + tooling — src/localdomain.ts re-exports localdomain.js; consumed by webpack.config.js (devServer port, cert paths, __API_HOST__ defines, proxies) and devserver.ts:250 (listens on apiPort, reads certs from ~/.secrets/live/<api domain>/).
• RN JS — src/App.native.tsx:30-34 sets __HOST__ / __API_HOST__ / __STREAMING_API_HOST__ from localdomain.js under __DEV__, so a native build in a worktree talks to that worktree's servers.
• Metro port, CLI side — scripts/metro-port.sh ($RCT_METRO_PORT → localdomain.js → 8081); used by the ios / android / rn:start npm scripts.
• Metro port, iOS side — RCT_METRO_PORT cannot work: React-Core is a prebuilt xcframework, so its default 8081 is compiled upstream. Instead ios/scripts/write-metro-port.sh runs as an always-out-of-date Debug build phase (project.pbxproj:933) and writes metro-port.txt into the app bundle; MetroLocation in ios/Liftosaur/AppDelegate.swift:104 reads it and pins jsLocation + packagerHost. Plain npm run ios and ⌘R in Xcode are both correct.
• Metro port, Android side — android/app/build.gradle:95 parses metroPort out of localdomain.js and emits resValue "integer", "react_native_dev_server_port".
• Metro isolation — metro.config.js block-lists worktrees/ and .claude/worktrees/ (anchored to the project root, so Metro still works when run from inside a worktree) to avoid haste-map collisions between duplicate package.jsons.

Remove

scripts/worktree-remove.sh <name>              # run from anywhere

Kills whatever is bound to its four ports, deletes the DNS records (guarded: refuses when main === "local"), deletes the cloned simulator, then git worktree remove --force and git branch -D. Certs are kept on purpose — same reason the index pool is small.

Gotchas

• Cloning the simulator fails while the golden sim is booted — xcrun simctl shutdown "iPhone 17e RNW", then re-run.
• DNS points at the LAN IP captured at create time. Change networks and every worktree's domain resolves to the wrong address. Re-run sh lambda/scripts/change_liftosaur_dev_api.sh "$PWD/localdomain.js".
• Certs live in ~/.secrets/live/<domain>/, shared across checkouts. If they're missing, webpack.config.js silently falls back to plain http while devserver.ts throws on readFileSync.
• Don't dismiss the RN redbox — -[RCTLogBoxView dealloc] → doesNotRecognizeSelector → SIGABRT. It usually means the worktree's servers aren't running; start them (or temporarily point localdomain.js at the base repo's local/8080/3000) instead of dismissing it.
• npm run pod-install dirties ios/Podfile.lock and ios/Liftosaur.xcodeproj/project.pbxproj — revert before committing feature work.
• Run npm run worktree:ios from the worktree root — it resolves ./localdomain and names the sim after basename $PWD, which must match the <name> worktree-remove.sh will be given.
• git worktree add -b <name> fails if the branch already exists. Create it from a fresh name, or git worktree add manually and write localdomain.js by hand.

Not per-worktree (known sharp edges)

• liftosaur-local MCP is pinned to https://local.liftosaur.com:8080/mcp (in ~/.claude.json). From a worktree it still talks to the base repo's server. Either run the base repo's npm start/start:server too, or repoint the MCP URL at the worktree's port for the session.
• Playwright hardcodes 8080 (playwright.config.ts:29, tests/playwrightUtils.ts:5) — the domain is per-worktree but the port isn't, so E2E runs from a worktree hit the base repo's web server.
• API CORS allow-list hardcodes 8080 (lambda/utils/response.ts:7), as do the OAuth/MCP redirect fallbacks (lambda/mcp/handler.ts, lambda/mcp/oauth.ts) and the dev CDK stack (liftosaur-cdk/liftosaur-cdk.ts). Cross-origin/OAuth flows may need the base ports.
• Android has no per-worktree provisioning — same package id (com.liftosaur.www.twa), one emulator, one install. Only the Metro port is worktree-aware. Two Android worktrees can't run side by side.
• .claude/worktrees/* are a different mechanism — created by the Claude Code harness (EnterWorktree), with no localdomain.js, ports, DNS or simulator. These scripts don't apply to them; they're only block-listed in Metro and excluded from copy:lambda.