From 12cd73bed9a817333c3499e67e18a4c3f59c0645 Mon Sep 17 00:00:00 2001
From: German Khokhlov <ouchlock@gmail.com>
Date: Tue, 3 Nov 2026 14:47:35 +0400
Subject: [PATCH] Skip CCTV scene work when its renderer was released during a
 health refresh

---
 src/layers/cctv/ingestion.js       | 14 +++++++++-----
 src/layers/cctv/ingestion.test.mjs | 24 ++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/src/layers/cctv/ingestion.js b/src/layers/cctv/ingestion.js
index 77d2c75e1..f80469769 100644
--- a/src/layers/cctv/ingestion.js
+++ b/src/layers/cctv/ingestion.js
@@ -43,12 +43,16 @@ export function createIngestion({
         }
       }
       await parts.health.syncHealthState();
-      // New health can change which camera wins a crowded cell.
-      if (layerState._enabled && parts.rendering.refreshHorizonCulling()) {
-        parts.geometryQueue.enqueueViewGeometry();
-        parts.cards.refreshAmbientCards();
+      // An engine switch can release the renderer while health loads. The
+      // scene work waits for the next renderer; health itself is kept.
+      if (parts.renderer) {
+        // New health can change which camera wins a crowded cell.
+        if (layerState._enabled && parts.rendering.refreshHorizonCulling()) {
+          parts.geometryQueue.enqueueViewGeometry();
+          parts.cards.refreshAmbientCards();
+        }
+        parts.navigation.maybeAutoHop(now);
       }
-      parts.navigation.maybeAutoHop(now);
       parts.presentation.notifyListeners();
       // Health and frame URL notifications update the panel directly. Media
       // requests its own frames; only actual scene changes need a tick frame.
diff --git a/src/layers/cctv/ingestion.test.mjs b/src/layers/cctv/ingestion.test.mjs
index dcb91792b..0fc0d72d7 100644
--- a/src/layers/cctv/ingestion.test.mjs
+++ b/src/layers/cctv/ingestion.test.mjs
@@ -12,6 +12,7 @@ function setup() {
   };
   const calls = { health: 0, notify: 0, queues: [] };
   const parts = {
+    renderer: {},
     rendering: { refreshHorizonCulling: () => false },
     model: { projectionTilesReady: () => true },
     ground: { isGroundResolved: () => false },
@@ -76,3 +77,26 @@ test('disabled CCTV does no polling or presentation work', async () => {
   await h.layer.update();
   assert.equal(h.calls.health + h.calls.notify + h.calls.queues.length, 0);
 });
+
+test('a tick resuming after an engine switch released the renderer does no scene work', async () => {
+  const h = setup();
+  let release;
+  h.parts.health.syncHealthState = () =>
+    new Promise((resolve) => {
+      release = resolve;
+    });
+  let sceneWork = 0;
+  h.parts.rendering.refreshHorizonCulling = () => {
+    sceneWork++;
+    return true;
+  };
+  h.parts.navigation.maybeAutoHop = () => {
+    sceneWork++;
+  };
+  const tick = h.layer.update();
+  h.parts.renderer = null;
+  release();
+  assert.deepEqual(await tick, { changed: false });
+  assert.equal(sceneWork, 0);
+  assert.equal(h.calls.notify, 1);
+});