---
phase: 01-ceiling-save-on-exit
plan: "01"
subsystem: devices
tags: [asyncio, context-manager, state-persistence, ceiling-light, tdd]

# Dependency graph
requires: []
provides:
  - CeilingLight.__aexit__ override that saves state to state_file before close()
  - TestCeilingLightSaveOnExit emulator test class (TEST-01/02/03)
affects: []

# Tech tracking
tech-stack:
  added: []
  patterns:
    - "Belt-and-braces __aexit__ override: save before super(), swallow I/O errors in try/except, chain super() unconditionally"
    - "RED/GREEN TDD: failing emulator tests committed first, then implementation"

key-files:
  created:
    - tests/test_devices/test_state_ceiling.py (TestCeilingLightSaveOnExit class appended)
  modified:
    - src/lifx/devices/ceiling.py (__aexit__ added after __aenter__)
    - tests/test_devices/test_state_ceiling.py (import json added; TestCeilingLightSaveOnExit appended)

key-decisions:
  - "Call _save_state_to_file() synchronously (no asyncio.to_thread) — matches all 8 existing call sites (D-01)"
  - "Guard if self._state_file: at call site in __aexit__ — makes CEIL-02 no-op explicit (D-02)"
  - "Belt-and-braces try/except in __aexit__ guard, separate from helper's own guard — CEIL-03 invariant survives future helper edits (D-03)"
  - "await super().__aexit__() unconditionally after save attempt — close() always runs (D-04)"
  - "Return None (implicit) from __aexit__ so body exceptions re-raise automatically (CEIL-03)"

patterns-established:
  - "CeilingLight async context manager: __aenter__ loads state, __aexit__ saves state, both chain to super()"

requirements-completed: [CEIL-01, CEIL-02, CEIL-03, CEIL-04, TEST-01, TEST-02, TEST-03]

# Metrics
duration: 6min
completed: 2026-06-12
---

# Phase 1 Plan 01: Ceiling Save-on-Exit Summary

**`CeilingLight.__aexit__` override that persists in-memory state to `state_file` before `close()`, proven by three emulator-backed TDD tests covering happy-path write, no-op without state_file, and exception-propagation-with-save-failure.**

## Performance

- **Duration:** 6 min
- **Started:** 2026-06-12T06:48:41Z
- **Completed:** 2026-06-12T06:54:17Z
- **Tasks:** 3
- **Files modified:** 2

## Accomplishments

- `CeilingLight.__aexit__` override implemented with belt-and-braces guard ensuring state is always saved before connection closes when `state_file` is set (CEIL-01)
- No-op when `state_file=None` — explicit guard at call site makes intent clear (CEIL-02)
- Body exceptions propagate unchanged; save I/O failures are logged at WARNING and swallowed (CEIL-03)
- Full pytest suite (2500 tests) green; pyright and ruff both clean (CEIL-04)

## Task Commits

Each task was committed atomically:

1. **Task 1: Add failing save-on-exit tests (RED)** — `0669bb3` (test)
2. **Task 2: Implement CeilingLight.__aexit__ (GREEN)** — `070bdba` (feat)
3. **Task 3: Phase quality gate (full suite + pyright + ruff)** — no file changes (quality gate only)

## Files Created/Modified

- `src/lifx/devices/ceiling.py` — `__aexit__` method added after `__aenter__` (lines 207-229)
- `tests/test_devices/test_state_ceiling.py` — `import json` added; `TestCeilingLightSaveOnExit` class appended

## Decisions Made

- `_save_state_to_file()` called synchronously (no `asyncio.to_thread`) — matches all 8 existing call sites
- `if self._state_file:` guard at `__aexit__` call site, in addition to the helper's own early-return — makes CEIL-02 explicit
- Belt-and-braces `try/except Exception` in `__aexit__` around the save, separate from the helper's own guard (D-03)
- `super().__aexit__()` called unconditionally so `close()` always runs regardless of save outcome (D-04)
- Log message references `self.serial` to distinguish the boundary-guard warning from the helper's internal warning which references `self._state_file`

## Deviations from Plan

None — plan executed exactly as written. ruff-format reformatted both files during pre-commit hooks (expected; hooks run on staged files).

## Issues Encountered

None — pre-commit hooks reformatted files twice (once per commit); restaged and committed cleanly each time.

## User Setup Required

None — no external service configuration required.

## Next Phase Readiness

- `CeilingLight` async context manager lifecycle now reliably persists state on exit
- No known stubs or incomplete wiring in the shipped code
- Phase 1 complete; this is the only plan in the phase

## Self-Check: PASSED

- `src/lifx/devices/ceiling.py` — FOUND (`async def __aexit__` at line 207)
- `tests/test_devices/test_state_ceiling.py` — FOUND (`class TestCeilingLightSaveOnExit` at line 431)
- `.planning/phases/01-ceiling-save-on-exit/01-01-SUMMARY.md` — FOUND
- Commit `0669bb3` — FOUND
- Commit `070bdba` — FOUND

---
*Phase: 01-ceiling-save-on-exit*
*Completed: 2026-06-12*
