Mark a resumed or share-restored follow only while it starts so a later follow of the same subject is navigation again

The aircraft scene binding re-tracked with origin share-restore, which stayed on the entity: a later trackedEntityChanged for it (cockpit exit, refocus) never stamped navigation, and the aircraft lost its selection origin. Flights, military and satellites now set a transient gevRestoring mark around follow.start, and the aircraft binding resumes with the origin the aircraft was selected by.

src/cameraHandoff.test.mjs

@@ -117,7 +117,7 @@ test('voice Cockpit entry reaches the camera only through stamping seams', () =>
   // Seam 1: a new tracker handoff stamps; restoring the session does not.
   assert.match(
     ui,
-    /viewer\.trackedEntityChanged\.addEventListener\(\s*\(entity\) => \{[\s\S]*?if \(\s*entity &&\s*!this\._disposed &&\s*entity\.gevSelectionOrigin !== 'share-restore'\s*\)\s*this\._stampNavigation\(\{\s*cancelPendingSelection: false,?\s*\}\);/,
+    /viewer\.trackedEntityChanged\.addEventListener\(\s*\(entity\) => \{[\s\S]*?if \(entity && !this\._disposed && !entity\.gevRestoring\)\s*this\._stampNavigation\(\{\s*cancelPendingSelection: false,?\s*\}\);/,
     'tracker handoff must stamp',
   );
   // Seam 2 is pinned by "Cockpit takeover invalidates deferred work" above.

src/layers/aircraft/sceneBinding.js

@@ -9,6 +9,9 @@ export function createAircraftSceneBinding({
   enable,
 }) {
   let resumeFollow = false;
+  // The tracked aircraft's selection origin outlives the renderer, as the
+  // tracking itself does.
+  let resumeOrigin = 'programmatic';
   function removeSceneListeners() {
     parts.tracking._removeClickHandler();
     services.picking.unregisterPickOwner(id);
@@ -58,7 +61,7 @@ export function createAircraftSceneBinding({
         parts.snapshots.presentRecords();
         if (flightState._trackedIcao) {
           parts.tracking._trackFlight(flightState._trackedIcao, {
-            origin: 'share-restore',
+            origin: resumeOrigin,
             resume: true,
             follow: resumeFollow,
           });
@@ -84,6 +87,8 @@ export function createAircraftSceneBinding({
       flightState._trackedCameraFrameStop?.();
       flightState._trackedCameraFrameStop = null;
       if (flightState._trackedEntity) {
+        resumeOrigin =
+          flightState._trackedEntity.gevSelectionOrigin ?? 'programmatic';
         resumeFollow = renderer.follow.isFollowing(flightState._trackedEntity);
         if (resumeFollow) renderer.follow.release();
         renderer.tracked.remove(flightState._trackedEntity);

src/layers/aircraft/sceneBinding.test.mjs

@@ -3,61 +3,165 @@ import test from 'node:test';
 import { createAircraftSceneBinding } from './sceneBinding.js';
 import { LayerBindings } from '../../ui/layerBindings.js';
 import { createEngineEvent } from '../../globe/contract.js';
+import { readLayerSource } from '../../testSupport/readLayerSource.mjs';
 
-test('resuming an aircraft on Cesium preserves the pending share navigation', (t) => {
+function observedShell(t) {
   const previous = globalThis.window;
   globalThis.window = new EventTarget();
   t.after(() => {
     globalThis.window = previous;
   });
   const trackedEntityChanged = createEngineEvent();
-  let generation = 1;
-  const shell = new LayerBindings({
+  const shell = {
+    generation: 1,
+    trackedEntityChanged,
+  };
+  const bindings = new LayerBindings({
     viewer: { trackedEntityChanged },
     services: {},
     operations: {
       _stampNavigation() {
-        generation++;
+        shell.generation++;
       },
     },
   });
-  shell.observeCamera();
-  t.after(() => shell.stop());
+  bindings.observeCamera();
+  t.after(() => bindings.stop());
+  return shell;
+}
+
+// What the tracking modules do around follow.start on a resume or a share
+// restore (flights, military and satellites tracking.js).
+function follow(trackedEntityChanged, entity, restoring) {
+  if (restoring) entity.gevRestoring = true;
+  try {
+    trackedEntityChanged.raiseEvent(entity);
+  } finally {
+    if (restoring) delete entity.gevRestoring;
+  }
+}
+
+function binding(flightState, tracked) {
   const renderer = {
-    fleet: { attach() {}, setVisible() {}, restoreOrder() {} },
-    models: { setVisible() {} },
+    fleet: {
+      attach() {},
+      detach() {},
+      setVisible() {},
+      restoreOrder() {},
+    },
+    models: { setVisible() {}, destroy() {} },
+    follow: {
+      isFollowing: () => true,
+      release() {},
+    },
+    tracked: { remove() {} },
+    destroy() {},
   };
-  let restored;
-  const binding = createAircraftSceneBinding({
+  return createAircraftSceneBinding({
     id: 'flights',
-    flightState: {
-      initialized: true,
-      _trackedIcao: 'a00000',
-      _preloadModel: {},
+    flightState,
+    services: {
+      renderer: { create: () => renderer },
+      render: { releaseContinuousRender() {} },
+      picking: { unregisterPickOwner() {} },
     },
-    services: { renderer: { create: () => renderer } },
     parts: {
       snapshots: { presentRecords() {} },
       tracking: {
-        _trackFlight(id, options) {
-          restored = { id, ...options };
-          trackedEntityChanged.raiseEvent({
-            gevSelectionOrigin: options.origin,
-          });
-        },
+        _trackFlight: tracked,
+        _removeClickHandler() {},
+        _detachTrail() {},
       },
+      rendering: { _releaseTrackedModel() {}, _releaseModels() {} },
+      motion: { _resetTrackedDisplay() {} },
     },
   });
-  binding.attachRenderer({});
+}
+
+test('resuming an aircraft on Cesium preserves the pending share navigation', (t) => {
+  const shell = observedShell(t);
+  let restored;
+  binding(
+    { initialized: true, _trackedIcao: 'a00000', _preloadModel: {} },
+    (id, options) => {
+      restored = { id, ...options };
+      follow(
+        shell.trackedEntityChanged,
+        { gevSelectionOrigin: options.origin },
+        options.resume,
+      );
+    },
+  ).attachRenderer({});
   assert.equal(restored.id, 'a00000');
   assert.equal(restored.resume, true);
   assert.equal(
-    generation,
+    shell.generation,
     1,
     'restored tracking cannot supersede and clear itself',
   );
   for (const origin of ['user', 'voice', 'programmatic']) {
-    trackedEntityChanged.raiseEvent({ gevSelectionOrigin: origin });
+    follow(shell.trackedEntityChanged, { gevSelectionOrigin: origin }, false);
+  }
+  assert.equal(
+    shell.generation,
+    4,
+    'new tracking still takes navigation authority',
+  );
+});
+
+test('a restored aircraft followed again later is new navigation', (t) => {
+  const shell = observedShell(t);
+  const entity = { gevSelectionOrigin: 'share-restore' };
+  follow(shell.trackedEntityChanged, entity, true);
+  assert.equal(shell.generation, 1);
+  assert.equal('gevRestoring' in entity, false, 'the mark does not stick');
+  // Cockpit exit or a refocus hands the same aircraft back to the camera.
+  shell.trackedEntityChanged.raiseEvent(undefined);
+  shell.trackedEntityChanged.raiseEvent(entity);
+  assert.equal(shell.generation, 2);
+});
+
+test('an engine switch resumes the aircraft with the origin it was selected by', () => {
+  const calls = [];
+  const flightState = {
+    initialized: true,
+    _trackedIcao: 'a00000',
+    _preloadModel: null,
+    _modelEpoch: 0,
+    _modelPending: new Map(),
+    _modelGen: new Map(),
+    _billboards: new Map(),
+    _cullPositions: new Map(),
+    _detectionObjects: new Set(),
+    _groundSnap: new Map(),
+  };
+  const scene = binding(flightState, (id, options) => calls.push(options));
+  flightState._preloadModel = {};
+  scene.attachRenderer({});
+  assert.equal(calls[0].origin, 'programmatic');
+  flightState._trackedEntity = { gevSelectionOrigin: 'voice' };
+  scene.detachRenderer({});
+  flightState._preloadModel = {};
+  scene.attachRenderer({});
+  assert.equal(calls[1].origin, 'voice');
+  assert.equal(calls[1].resume, true);
+  assert.equal(calls[1].follow, true);
+});
+
+test('every follow of a resumed or share-restored subject is marked while it starts', () => {
+  for (const [file, resume] of [
+    ['flights/tracking.js', 'resume'],
+    ['military/tracking.js', 'resume'],
+    ['satellites/tracking.js', 'resuming'],
+  ]) {
+    const source = readLayerSource(new URL(`../${file}`, import.meta.url));
+    assert.match(
+      source,
+      new RegExp(
+        `const restoring = ${resume} \\|\\| origin === 'share-restore';\\s*if \\(restoring\\) entity\\.gevRestoring = true;\\s*try \\{[\\s\\S]*?follow\\.start\\(entity\\);?\\s*\\} finally \\{\\s*if \\(restoring\\) delete entity\\.gevRestoring;`,
+      ),
+      file,
+    );
+    assert.equal(source.match(/follow\.start\(/g).length, 1, file);
   }
-  assert.equal(generation, 4, 'new tracking still takes navigation authority');
 });

src/layers/flights/tracking.js

@@ -1011,10 +1011,20 @@ export function createTracking({
     refreshTrackedReadout(flightState._trackedEntity);
     // Camera follows the tracked entity (the renderer cancels any flight
     // first and applies the one exact tracked frame).
+    // A resumed binding or a share restore re-follows the session's own
+    // subject: marked only while the follow starts, so the shell does not
+    // read it as new navigation (LayerBindings.observeCamera) yet any later
+    // follow of the same aircraft still is.
     if (follow) {
-      flightState._trackedCameraFrameStop = flightState._renderer.follow.start(
-        flightState._trackedEntity,
-      );
+      const entity = flightState._trackedEntity;
+      const restoring = resume || origin === 'share-restore';
+      if (restoring) entity.gevRestoring = true;
+      try {
+        flightState._trackedCameraFrameStop =
+          flightState._renderer.follow.start(entity);
+      } finally {
+        if (restoring) delete entity.gevRestoring;
+      }
     }
 
     // Track-history trail (PRD F1): seed from local history + async backfill.

src/layers/military/tracking.js

@@ -971,10 +971,20 @@ export function createTracking({
     refreshTrackedReadout(flightState._trackedEntity);
     // Camera follows the tracked entity (the renderer cancels any flight
     // first and applies the one exact tracked frame).
+    // A resumed binding or a share restore re-follows the session's own
+    // subject: marked only while the follow starts, so the shell does not
+    // read it as new navigation (LayerBindings.observeCamera) yet any later
+    // follow of the same aircraft still is.
     if (follow) {
-      flightState._trackedCameraFrameStop = flightState._renderer.follow.start(
-        flightState._trackedEntity,
-      );
+      const entity = flightState._trackedEntity;
+      const restoring = resume || origin === 'share-restore';
+      if (restoring) entity.gevRestoring = true;
+      try {
+        flightState._trackedCameraFrameStop =
+          flightState._renderer.follow.start(entity);
+      } finally {
+        if (restoring) delete entity.gevRestoring;
+      }
     }
     if (resume) {
       _attachTrail();

src/layers/satellites/tracking.js

@@ -485,7 +485,16 @@ export function createTracking({
       layerState._contextRefreshedAtMs = Date.now();
     }
 
-    getRenderer().follow.start(layerState._trackedEntity);
+    // Resumed or share-restored: not new navigation, only while the follow
+    // starts (see flights/tracking.js).
+    const entity = layerState._trackedEntity;
+    const restoring = resuming || origin === 'share-restore';
+    if (restoring) entity.gevRestoring = true;
+    try {
+      getRenderer().follow.start(entity);
+    } finally {
+      if (restoring) delete entity.gevRestoring;
+    }
     console.log(`[Data:Satellites] Tracking ${name} (NORAD ${noradId})`);
   }
   return {

src/ui/layerBindings.js

@@ -86,13 +86,10 @@ export class LayerBindings {
     if (this.viewer)
       this._navigationOwnerChangedRemover =
         this.viewer.trackedEntityChanged.addEventListener((entity) => {
-          // Rebinding the session's aircraft is part of the pending share
-          // restoration, not a new navigation that supersedes that restore.
-          if (
-            entity &&
-            !this._disposed &&
-            entity.gevSelectionOrigin !== 'share-restore'
-          )
+          // Rebinding the session's subject (a resumed renderer, a share
+          // restore) is part of the pending restoration, not a new navigation
+          // that supersedes it. The mark lasts only while the follow starts.
+          if (entity && !this._disposed && !entity.gevRestoring)
             this._stampNavigation({ cancelPendingSelection: false });
         });
     // Vessel/installation focus flies without ever assigning a tracked entity,