fix(k1): restore low-latency live recovery path

tests/test_xgrids_camera_gateway.py

@@ -6,6 +6,7 @@ import json
 import sys
 import threading
 import time
+from collections.abc import Callable
 from io import BytesIO
 from pathlib import Path
 
@@ -1416,16 +1417,60 @@ def test_source_end_none_epoch_cas_waits_for_canonical_archive_seal(
         gateway.close()
 
 
+def test_acquisition_candidate_never_spawns_before_authority_reservation(
+    tmp_path: Path,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setenv("MISSIONCORE_FFMPEG_BINARY", str(_silent_ffmpeg(tmp_path)))
+    session = tmp_path / "sessions" / "camera-pre-popen-denied"
+    session.mkdir(parents=True)
+    gateway = XgridsK1CameraGateway(tmp_path, XGRIDS_K1_PLUGIN_ID)
+    popen_called = False
+
+    def forbidden_popen(*_: object, **__: object) -> object:
+        nonlocal popen_called
+        popen_called = True
+        raise AssertionError("FFmpeg must not start before authority reservation")
+
+    monkeypatch.setattr(camera_module.subprocess, "Popen", forbidden_popen)
+    try:
+        with pytest.raises(ValueError, match="authority"):
+            gateway.activate_recording_producer(
+                "sensor.camera.right",
+                "192.168.1.20",
+                session,
+                pre_prepare_fence=lambda _reserve: False,
+                commit_fence=lambda commit: commit(),
+            )
+
+        snapshot = gateway.snapshot()
+        assert popen_called is False
+        assert snapshot["active_source_id"] is None
+        assert snapshot["recording"]["active"] is False
+    finally:
+        gateway.close()
+
+
 def test_acquisition_candidate_binds_epoch_before_any_reader_thread_starts(
     tmp_path: Path,
     monkeypatch: pytest.MonkeyPatch,
+    caplog: pytest.LogCaptureFixture,
 ) -> None:
     monkeypatch.setenv("MISSIONCORE_FFMPEG_BINARY", str(_silent_ffmpeg(tmp_path)))
     session = tmp_path / "sessions" / "camera-bind-before-reader"
     session.mkdir(parents=True)
     gateway = XgridsK1CameraGateway(tmp_path, XGRIDS_K1_PLUGIN_ID)
+    caplog.set_level("INFO", logger="k1link.device_plugins.xgrids_k1.camera")
     bound_generation: list[int] = []
     reader_start_generation: list[int] = []
+    authority_reserved = False
+
+    def reserve_authority(reserve: Callable[[], bool]) -> bool:
+        nonlocal authority_reserved
+        assert authority_reserved is False
+        assert reserve() is True
+        authority_reserved = True
+        return True
 
     def bind(committed: dict[str, object]) -> None:
         recording = committed["recording"]
@@ -1436,6 +1481,7 @@ def test_acquisition_candidate_binds_epoch_before_any_reader_thread_starts(
 
     def start_threads(producer: object) -> None:
         generation = producer.generation  # type: ignore[attr-defined]
+        assert authority_reserved is True
         assert bound_generation == [generation]
         reader_start_generation.append(generation)
 
@@ -1445,6 +1491,7 @@ def test_acquisition_candidate_binds_epoch_before_any_reader_thread_starts(
             "sensor.camera.right",
             "192.168.1.20",
             session,
+            pre_prepare_fence=reserve_authority,
             commit_fence=lambda commit: commit(),
             committed_before_start=bind,
         )
@@ -1452,6 +1499,16 @@ def test_acquisition_candidate_binds_epoch_before_any_reader_thread_starts(
         assert bound_generation == [activated["recording"]["active_epoch"]]
         assert reader_start_generation == bound_generation
         assert activated["recording"]["media_ready"] is False
+        timing = [
+            record
+            for record in caplog.records
+            if getattr(record, "event_code", None) == "k1_camera_activation_timing"
+        ]
+        assert len(timing) == 1
+        assert timing[0].camera_generation == bound_generation[0]
+        assert timing[0].camera_authority_wait_ms >= 0
+        assert timing[0].camera_ffmpeg_prepare_ms >= 0
+        assert timing[0].camera_post_spawn_commit_ms >= 0
     finally:
         gateway.close()