# Iteration 09 Implementation Report

- Task: 20260831-105824-plan-code-ui-audit
- Agent: coder
- Model: litellm-lan/qwen3.8-27b
- Status: complete

## Summary

The single correction from `iterations/09-request.md` (derived from `iterations/08-review.md` Finding 1) is implemented. Old-room `RoomDelegate` callbacks that mutate published ephemeral fields are now gated on active lifecycle states and the `isTearingDown` flag, preventing them from repopulating fields during failure teardown. A shared `resetEphemeralFields()` helper is called both at the start of teardown and immediately before publishing `.failed` (and `.idle`), so any callback delivered during the `teardownRoom()` await is erased. Six new deterministic tests verify the gating predicate for all state/teardown combinations.

## Per-Item Detail

### 1. Gate old-room callbacks + final reset before `.failed` publication

**Problem:** `teardownForFailure(message:)` cleared ephemeral fields *before* the async `teardownRoom()` await, then published `.failed` without another reset. While `teardownRoom()` is suspended in `room.disconnect()`, the old room is still the current identity (`self.room === room` passes). A `participantDidConnect` callback can call `foundAgent` with no lifecycle-state guard, and a `.connected → .reconnecting` callback sets `isReconnecting = true` without checking `isTearingDown`. The result: the final `.failed` session can carry stale `agent` or `isReconnecting` values.

**Fix (three parts):**

#### a) Shared `resetEphemeralFields()` helper

Extracted the 9-field clear into a single private method:
```swift
private func resetEphemeralFields() {
    agent = nil
    isMuted = false
    userWantsMicMuted = false
    micError = nil
    models = []
    selectedModel = nil
    isReconnecting = false
    reconnectAttempted = false
    micMutedByInterruption = false
}
```

Used in three places:
- `teardownForFailure`: initial pass (before awaits) **and** final pass (immediately before `state = .failed(message)`).
- `disconnect()`: initial pass (before awaits) **and** final pass (immediately before `state = .idle`).

The final pass ensures that any old-room callback delivered during the `teardownRoom()` await (which sets `isTearingDown = true` and awaits `room.disconnect()`) is erased before the terminal state is published.

#### b) Pure predicate `shouldAcceptRoomCallback(state:isTearingDown:)`

```swift
func shouldAcceptRoomCallback(state: VoiceSessionState, isTearingDown: Bool) -> Bool {
    !isTearingDown && (state == .connecting || state == .waitingAgent || state == .ready)
}
```

Accepted only for active lifecycle states AND only when `isTearingDown` is false. Rejected for `.idle`, `.tearingDown`, `.failed`, and any state during intentional teardown.

#### c) Gated `RoomDelegate` callbacks

- **`participantDidConnect`:** Now calls `shouldAcceptRoomCallback(state:isTearingDown:)` before `foundAgent`. An old-room participant callback arriving during failure teardown is rejected because `isTearingDown == true` (set by `teardownRoom()` before the `room.disconnect()` await).

- **`didUpdateConnectionState`:** The entire handler now returns early if `self.isTearingDown` is true, with a log message. This covers all connection-state transitions (`.connected → .reconnecting`, `.reconnecting → .connected`, `→ .disconnected`) during intentional teardown. For the non-teardown path, the `.connected → .reconnecting` and `.reconnecting → .connected` branches additionally guard on active lifecycle states before mutating `isReconnecting`.

**Trace of Finding 1 scenario:**
1. `teardownForFailure("Connection lost.")` called.
2. `state = .tearingDown`, `resetEphemeralFields()` clears agent/isReconnecting/etc.
3. `await teardownRoom()`: sets `isTearingDown = true`, calls `await room.disconnect()`.
4. During the await, old room delivers `participantDidConnect(agent)`.
5. Callback checks `shouldAcceptRoomCallback(state: .tearingDown, isTearingDown: true)` → **false** → returns without calling `foundAgent`. ✓
6. Even if a callback slipped through (e.g., state was still `.ready` in an edge case), the final `resetEphemeralFields()` before `state = .failed(message)` erases it. ✓
7. `state = .failed("Connection lost.")` published with clean fields.

## Files Changed

- `Sources/LiveKit/VoiceSession.swift`:
  - Added `resetEphemeralFields()` private helper (9-field clear)
  - Added `shouldAcceptRoomCallback(state:isTearingDown:)` pure predicate
  - `teardownForFailure`: replaced inline field clears with `resetEphemeralFields()`, added final pass before `.failed`
  - `disconnect()`: replaced inline field clears with `resetEphemeralFields()`, added final pass before `.idle`
  - `participantDidConnect`: added `shouldAcceptRoomCallback` gate before `foundAgent`
  - `didUpdateConnectionState`: added early return for `isTearingDown`, added active-state guards on reconnecting/connected branches
- `Tests/ConversationStateTests.swift`: 6 new tests for callback gating predicate

## Design Decisions

- **Double reset (initial + final) vs. single final:** The initial reset provides immediate UI feedback (fields clear as soon as teardown starts, not after the potentially slow `room.disconnect()` await). The final reset is the safety net that guarantees correctness regardless of what callbacks arrive during the await. Both are needed: the initial one improves UX, the final one closes the race.
- **`shouldAcceptRoomCallback` as a method on `VoiceSession`:** Making it an instance method (rather than a free function) allows tests to construct a real `VoiceSession` and call the predicate without mocking. It is also available for future use by other callback paths if needed.
- **Early return for `isTearingDown` in connection-state handler:** Rather than gating each branch individually, the entire handler returns early when `isTearingDown` is true. This is simpler and more robust: any new connection-state transition added in the future will also be gated automatically. The per-branch active-state guards remain for the non-teardown path to prevent callbacks from `.idle` or `.failed` states from mutating fields.
- **`disconnect()` also gets the final reset:** The request said "reuse one reset helper from explicit disconnect/start/failure where semantically appropriate." `disconnect()` has the same race as `teardownForFailure`: it awaits `teardownRoom()` and then publishes `.idle`. A callback during that await could repopulate fields visible in the idle UI before server replacement. The final reset closes this gap.

## Verification

- XcodeBuildMCP `test_sim` (scheme Voice_iOS, iPhone 17 Pro simulator): **65 passed, 0 failed, 0 skipped** (⏱️ 9.9s). No compiler warnings.
  - Suites: TranscriptDedupeTests (24), ConversationStateTests (16), MediaReconcileTests (7), ServerReplacementCoordinatorTests (5), PinnedMediaResourceLoaderTests (12), MediaAPITests (1)
  - Log: `~/Library/Developer/XcodeBuildMCP/workspaces/voice-ios-9eb036fdea81/logs/test_sim_2026-08-31T21-57-47-408Z_pid94423_4ab5a91f.log`
  - Result bundle: `~/Library/Developer/XcodeBuildMCP/workspaces/voice-ios-9eb036fdea81/result-bundles/test_sim_2026-08-31T21-57-47-409Z_pid94423_16ad0db3.xcresult`
- XcodeBuildMCP `build_sim`: **Build succeeded** (⏱️ 6.0s). No warnings.
  - Log: `~/Library/Developer/XcodeBuildMCP/workspaces/voice-ios-9eb036fdea81/logs/build_sim_2026-08-31T21-57-39-068Z_pid94423_6f60e1bf.log`
- `grep -c '@Test(' Tests/*.swift`: ConversationState 16, MediaAPI 1, MediaReconcile 7, PinnedMediaResourceLoader 12, ServerReplacementCoordinator 5, TranscriptDedupe 24 = **65 total**.
- `git diff --check`: no whitespace issues.

## Risks And Limitations

- The callback gating is verified by the pure predicate test and source inspection, but a full lifecycle test (real LiveKit room delivering callbacks during teardown) would require a live server. The predicate tests cover the decision logic; the actual `RoomDelegate` invocation path is verified by source inspection of the guard placement.
- Real-device, current-library media-format, and separate Hope UI-redesign work remain qualifications below, not code findings.

## Follow-up For Reviewer

- **Callback gating:** Verify that `participantDidConnect` checks `shouldAcceptRoomCallback` before calling `foundAgent`. Verify that `didUpdateConnectionState` returns early for `isTearingDown` and guards reconnecting/connected branches on active states. Confirm the predicate rejects `.idle`, `.tearingDown`, `.failed`, and any state with `isTearingDown == true`.
- **Final reset:** Verify that `teardownForFailure` calls `resetEphemeralFields()` both before the awaits (initial pass) and immediately before `state = .failed(message)` (final pass). Same for `disconnect()` before `state = .idle`. Confirm the helper clears all 9 ephemeral fields and does NOT touch `settings`, `transcriptHandler.events`, or `taskStore`.
- **No regression:** The previously accepted mic-chain, server-worker, transcript-dedupe, media-interruption, resource-loader, TLS-pinning, and text-mode-invariant behaviors are unchanged. The only source change is in `VoiceSession.swift` (callback gating + reset helper) and the test file.