> Recreates #543 — GitHub auto-closed it when the base branch of the
stacked PR (#542) was deleted on merge, and a closed PR cannot be
reopened after its head is force-pushed. Same commit, rebased onto main.
## Summary
**Was stacked on #542** (now merged). Consumes the
`ios.additionalDeviceSets` configuration across the iOS tool surface, so
simulators living in extra CoreSimulator device sets — e.g. **Radon
IDE's** `~/Library/Caches/com.swmansion.radon-ide/Devices/iOS` — are
discovered by `list-devices` and drivable by every tool, by UDID,
exactly like default-set devices.
### The core piece: a UDID → device-set map (`utils/ios-device-sets.ts`)
simctl scopes every operation to one device set, so each per-device call
must know the target's owning set. The new module owns that mapping and
the single argv choke point:
- **Learned from discovery**: `list-devices` and the simulator watcher
enumerate the default set + every configured set and `rememberDeviceSet`
each sighting — any tool used after a list hits a warm cache.
- **Lazy fallback**: an unknown UDID triggers one `simctl list` probe
per configured set, cached on hit. An unknown-everywhere UDID resolves
to the default set **without** caching (a device that appears later is
found on the next call) — preserving pre-feature behavior and error
messages byte-for-byte.
- **`simctlArgsForUdid(udid, args)`** builds the full argv (`--set`
injected only for additional-set devices); `simctlPrefix` covers
multi-call sites that resolve once; sync variants
(`simctlArgsForUdidSync`, `cachedDeviceSetForUdid`) cover the
`ChildProcess`-returning and `execFileSync` call sites, each of which
runs after an async step that warmed the cache.
- Config is **read off disk per call** (the #534 design): editing
`ios.additionalDeviceSets` applies without a tool-server restart.
- **Guard**: a configured set whose directory doesn't exist is never
queried — simctl would materialize the dir, turning a config typo into a
stray directory.
### Wired consumers
- **`list-devices`** — enumerates every set, tags additional-set devices
with `deviceSet`, documents the field.
- **`simulator-watcher`** — polls every set (a set failing to list
throws → the tick is skipped, so a transient error still can't
mass-dispose tracked services); warms the map for the injection path.
- **simulator-server blueprint** — passes `--device-set` (the same flag
Radon IDE passes to this shared binary); default-set spawns unchanged.
- **`ax-prefs`** — the pre-boot AX plist now lands under the owning
set's device dir (previously hardcoded to the default
`CoreSimulator/Devices` root, so the write would land nowhere for these
devices and describe would degrade).
- **`boot-device`** — set-aware shutdown/boot/bootstatus; skips the
Simulator.app attach + `CurrentDeviceUDID` write for additional-set
devices (one Simulator.app instance displays one device set — these run
headless and are streamed, exactly how Radon IDE presents them).
- **Every remaining per-device simctl call site**: launch-app /
restart-app / reinstall-app (both the direct impls and the
`SimctlBackend` shared handlers), open-url, settings-permissions
(privacy + install probe), the tvOS screenshot fallback, status-bar
pin/restore, device-shutdown, the ios-host `simctl spawn` family behind
describe/native-devtools, tv-control's AX daemon, and the native
profiler's sync helpers (cache warmed at `startNativeProfilerIos`).
**Out of scope**: `sim-remote` — the remote orchestrator host has its
own device-set story.
## Testing
- **Unit**: new `ios-device-sets.test.ts` (mapping, lazy probe + caching
semantics, no-probe fast path with no sets configured, discovery
enumeration/tagging/dedup, missing-dir guard); blueprint test asserts
the `--device-set` argv; the profiler shell-injection mock extended for
the new import. Full tool-server suite green: **276 files / 2752
tests**; `tsc --build`, eslint, prettier clean.
- **Live, end-to-end on a real Radon IDE device** (iPhone Air, iOS 26.4,
in `com.swmansion.radon-ide/Devices/iOS`), driving this branch's
tool-server over HTTP with the config set at project scope:
- `list-devices` → the Radon device appears, tagged with its `deviceSet`
(invisible to argent 0.16.1 on the same machine);
- `boot-device` → boots headless in its set, no Simulator.app window;
- `screenshot` → real home-screen PNG via simulator-server spawned with
`--device-set`;
- `launch-app` (Settings) → launched via `simctl --set launch`;
- `describe` → full accessibility tree from the Settings screen, i.e.
the AX bootstrap (set-aware prefs + in-sim ax-service daemon via `simctl
--set spawn`) works;
- clean shutdown; default-set devices meanwhile listed and behaved
exactly as before.
filip131311