# Story 3.2: Automatic Recovery on Fresh Decode

Status: done

## Story

As a user whose RTL-SDR has recovered,
I want the display to automatically return to normal filled aircraft rendering on the next successful fetch,
So that recovery requires no intervention.

## Acceptance Criteria

AC1: **Given** the display is in stale state **When** `HttpFetcher.fetch()` returns a non-empty aircraft list **Then** all fetched aircraft have `is_stale=False` and are drawn with normal filled icons

AC2: **Given** the display has recovered **When** the next render cycle runs **Then** no stale outline rendering occurs for the recovered aircraft

AC3: **Given** a stale-then-recovery sequence **When** `FileFixtureFetcher` first returns `[]` (simulating stale) then returns a populated list **Then** the first cycle produces stale aircraft and the second produces normal fresh aircraft

## Tasks / Subtasks

- [ ] Task 1: Add recovery tests to `tests/test_stale.py` (AC: #1, #2, #3)
  - [ ] 1.1 Add `test_recovery_after_timeout_returns_fresh`
  - [ ] 1.2 Add `test_recovery_after_empty_returns_fresh`
  - [ ] 1.3 Verify no code changes needed in `main.py` or `aircraft.py` — recovery is already correct

- [ ] Task 2: Run quality gates
  - [ ] 2.1 `python -m pytest tests/` — all tests pass
  - [ ] 2.2 `python -m ruff check .` — zero violations
  - [ ] 2.3 `python -m ruff format --check .` — no formatting issues

## Implementation Notes

### Recovery logic already correct from story 3-1

The `_run_one_cycle()` stale detection logic in `main.py` is:

```python
try:
    fresh = fetcher.fetch()
except requests.Timeout:
    log.warning("fetch timeout — using stale data")
    fresh = []
    stale_needed = True
else:
    stale_needed = (len(fresh) == 0 and len(last_aircraft) > 0)

if stale_needed:
    aircraft_list = [dataclasses.replace(a, is_stale=True) for a in last_aircraft]
else:
    aircraft_list = fresh
```

When `len(fresh) > 0`, `stale_needed` is `False` and `aircraft_list = fresh`. All `Aircraft` instances from a fresh fetch default `is_stale=False`, so recovery is automatic — no code changes required.

### No changes to `main.py` or `aircraft.py`

Recovery is already handled correctly. The only deliverable is two additional tests in `tests/test_stale.py` confirming the recovery path for both the timeout-then-fresh and empty-then-fresh scenarios.

### Files changed

| File | Change |
|---|---|
| `tests/test_stale.py` | Add `test_recovery_after_timeout_returns_fresh` and `test_recovery_after_empty_returns_fresh` |
