Resume offline preparation on launch and show cache readiness

frontend/app.js

@@ -8690,11 +8690,11 @@ async function applyUpdate(target, { quiet = false } = {}) {
       // When the waiting worker already downloaded this build in the
       // background, the toast says so and nothing is re-downloaded.
       askStatus: (worker) => SU.askCacheStatus(worker, { timeoutMs: 4000, setTimeout: (fn, ms) => setTimeout(fn, ms) }),
-      onPhase: (phase) => {
+      onPhase: (phase, status) => {
         if (quiet) return;
         if (_updateToast) _updateToast.remove();
         _updateToast = phase === 'ready'
-          ? toast('Applying the update…', { duration: 20000 })
+          ? toast(status?.offlineReady === false ? `Applying the update… Offline cache is still preparing (${status.cached}/${status.total}).` : 'Applying the update…', { duration: 20000 })
           : toast('Downloading the update…', { duration: 305000 });
       },
       refreshShell: ('caches' in window) ? () => SU.refreshShellInPlace({

frontend/lazy.js

@@ -100,9 +100,10 @@
       else root.navigator.serviceWorker?.getRegistration().then(send).catch(()=>{});
     },
     warm() {
-      if(root.navigator.connection?.saveData || !root.navigator.serviceWorker) return;
+      if (!root.navigator.serviceWorker || root.navigator.onLine === false) return;
-      const idle = root.requestIdleCallback || (fn => root.setTimeout(fn,1000));
+      root.navigator.serviceWorker.ready.then(reg => {
-      idle(()=>root.navigator.serviceWorker.ready.then(reg=>reg.active?.postMessage({type:'WARM_ASSETS',saveData:!!root.navigator.connection?.saveData})).catch(()=>{}));
+        for (const worker of new Set([reg.active, reg.waiting])) worker?.postMessage({type:'COMPLETE_ASSETS'});
+      }).catch(()=>{});
     },
     onLoad(name, fn) {
       if(api.loaded(name)) { Promise.resolve().then(fn).catch(error=>{if(root.CustomEvent)root.dispatchEvent?.(new root.CustomEvent('ytp-lazy-error',{detail:{group:name,error}}));}); return; }
@@ -128,6 +129,8 @@
     if(event.data?.type==='SW_UPDATE_AVAILABLE') api.warm();
   });
   root.navigator.serviceWorker?.addEventListener('controllerchange',()=>{api.reportLayout();api.warm();});
+  root.addEventListener?.('online',()=>api.warm());
+  api.warm();
   let settings={};
   try { settings=JSON.parse(root.localStorage.getItem('_ytpdata') || '{}').settings || {}; api.layout=settings.layout || 'classic'; } catch {}
   Object.assign(doc.documentElement.dataset,{layout:api.layout,theme:settings.theme || 'dark',font:settings.fontScale || 'normal',density:settings.density || 'comfortable',perf:settings.perfMode?'on':'off',motion:settings.reduceMotion?'reduced':'full'});

frontend/lazy.test.js

@@ -84,3 +84,14 @@ test('classic chunk registry proxies use window.YT and keep the executed singlet
  const singleton=root.YT.TestApi;await root.Lazy.load('feature:test');
  assert.equal(root.YT.TestApi,singleton);assert.equal(inserted.length,2);
 });
+
+
+test('online launches request worker completion even with Save-Data and skip offline messages',async()=>{
+ const f=fixture(),sent=[];
+ const active={postMessage:m=>sent.push(m)},waiting={postMessage:m=>sent.push(m)};
+ f.root.navigator.connection={saveData:true};f.root.navigator.onLine=true;
+ f.root.navigator.serviceWorker={ready:Promise.resolve({active,waiting})};
+ f.root.Lazy.warm();await Promise.resolve();
+ assert.deepEqual(sent.map(m=>m.type),['COMPLETE_ASSETS','COMPLETE_ASSETS']);
+ f.root.navigator.onLine=false;f.root.Lazy.warm();await Promise.resolve();assert.equal(sent.length,2);
+});

frontend/sw-update.js

@@ -250,14 +250,15 @@
     // Opt-in: without an askStatus the download path runs exactly as before.
     // (It must never be implicit — a probe that waits on a reply would hang
     // forever if the caller injected a setTimeout that never fires.)
-    let precached = false;
+    let precached = false, offlineStatus;
     if (waiting && askStatus) {
       try {
         const status = await askStatus(waiting);
         precached = !!(status && status.ready);
+        offlineStatus = status;
       } catch { precached = false; }
     }
-    if (onPhase) onPhase(precached ? 'ready' : 'downloading');
+    if (onPhase) onPhase(precached ? 'ready' : 'downloading', offlineStatus);
     if (!precached && refreshShell) await refreshShell();
 
     if (!guard()) throw new Error('Playing - update after this song / when paused');
@@ -280,7 +281,25 @@
     waiting.postMessage({ type: 'SKIP_WAITING' });
   }
 
-  const SwUpdate = { applyUpdate, refreshShellInPlace, askCacheStatus, BUST_PARAM };
+  function showOfflineStatus(status) {
+    const el = root.document?.getElementById('offlineAssetStatus');
+    if (el && typeof status?.total === 'number') {
+      el.textContent = `${status.offlineReady ? 'Offline ready' : 'Preparing offline'} ${status.cached}/${status.total}`;
+    } else if (el && typeof status?.ready === 'boolean') {
+      el.textContent = status.ready ? 'Offline ready (legacy cache)' : 'Offline cache incomplete (legacy mode)';
+    }
+  }
+  async function offlineStatus() {
+    const registration = await root.navigator?.serviceWorker?.getRegistration();
+    const status = await askCacheStatus(registration?.active);
+    showOfflineStatus(status);
+    return status;
+  }
+  root.navigator?.serviceWorker?.addEventListener?.('message', event => {
+    if (event.data?.type === 'OFFLINE_STATUS') showOfflineStatus(event.data);
+  });
+
+  const SwUpdate = { offlineStatus, showOfflineStatus, applyUpdate, refreshShellInPlace, askCacheStatus, BUST_PARAM };
 
   if (typeof module !== 'undefined' && module.exports) {
     module.exports = SwUpdate;

frontend/sw-update.test.js

@@ -368,3 +368,22 @@ test('an unanswered worker status cannot fall through to an empty legacy refresh
  vm.runInNewContext(fs.readFileSync(__dirname+'/sw-update.js','utf8'),sandbox);
  await assert.rejects(sandbox.SwUpdate.refreshShellInPlace({cachesApi:{open:async()=>({}),keys:async()=>[]},fetchFn:async()=>({ok:true,json:async()=>({buildTag:'new'})}),isShellCache:()=>true}),/Worker update status unavailable/);
 });
+
+
+test('update readiness retains completion progress without blocking the ready fast path',async()=>{
+ const phases=[],container=fakeContainer();let downloaded=false;
+ const status={ready:true,offlineReady:false,cached:90,total:151,missingFiles:['/optional.js']};
+ await applyUpdate({reg:{waiting:{postMessage(){}}},container,askStatus:async()=>status,
+  onPhase:(phase,progress)=>phases.push({phase,progress}),refreshShell:async()=>{downloaded=true;},setTimeout:()=>{}});
+ assert.equal(downloaded,false);assert.equal(phases[0].phase,'ready');assert.deepStrictEqual(phases[0].progress,status);
+});
+test('offline cache status reports preparing and complete counts in Settings',()=>{
+ const vm=require('node:vm'),fs=require('node:fs'),element={};
+ const sandbox={document:{getElementById:()=>element}};
+ vm.runInNewContext(fs.readFileSync(__dirname+'/sw-update.js','utf8'),sandbox);
+ sandbox.SwUpdate.showOfflineStatus({offlineReady:false,cached:90,total:151});
+ assert.equal(element.textContent,'Preparing offline 90/151');
+ sandbox.SwUpdate.showOfflineStatus({offlineReady:true,cached:151,total:151});
+ assert.equal(element.textContent,'Offline ready 151/151');
+ sandbox.SwUpdate.showOfflineStatus({ready:true});assert.equal(element.textContent,'Offline ready (legacy cache)');
+});

frontend/views-core.js

@@ -843,6 +843,7 @@ async function renderSettings() {
 
     <div class="set-group">
       <div class="set-group-title">Offline cache</div>
+      <div class="set-row"><span>App &amp; features</span><small id="offlineAssetStatus" role="status">Checking offline readiness…</small></div>
       <label class="set-row">
         <span>
           Auto-save playlist videos
@@ -1186,6 +1187,8 @@ async function renderSettings() {
     fold.addEventListener('toggle', () => { try { localStorage.setItem('ytpCacheFoldOpen', fold.open ? '1' : '0'); } catch { /* blocked */ } });
   }
 
+  window.SwUpdate?.offlineStatus().catch(() => {});
+
   // ---- Populate live cache stats ----
   try {
     const res = await API.cacheList();