Verify explicit activation and legacy incremental migration

frontend/asset-worker.test.js

@@ -9,4 +9,4 @@ function environment(){
  return {storage,m,skips,dispatch,request};
 }
 test('install does not activate or publish; CACHE_STATUS is honest; activation commits and exact requests self-heal',async()=>{const e=environment();await e.dispatch('install');assert.equal(e.skips.length,0);const cache=await e.storage.open(core.CACHE);assert.equal(await core.state(cache),null);let reply;await e.dispatch('message',{data:{type:'CACHE_STATUS'},ports:[{postMessage:r=>reply=r}]});assert.equal(reply.ready,true);await e.dispatch('activate');assert.equal((await core.state(cache)).current.buildTag,'next');assert.equal((await e.request('/playlist/x','navigate')).headers.get('X-Asset-Hash'),'index');await cache.delete('/app.js?v=app');await e.dispatch('message',{data:{type:'CACHE_STATUS'},ports:[{postMessage:r=>reply=r}]});assert.equal(reply.ready,false);assert.equal(reply.missing,1);assert.equal(reply.version,'next');assert.equal((await e.request('/app.js')).headers.get('X-Asset-Hash'),'app');assert.ok(await cache.match('/app.js?v=app'));assert.equal(await cache.match('/app.js?v=stale'),undefined);assert.equal((await e.request('/app.js?v=stale')).status,409);});
-test('reported playback defers explicit activation until pause; install never calls skipWaiting',async()=>{const e=environment(),source={id:'p'};await e.dispatch('message',{source,data:{type:'PLAYING',value:true}});await e.dispatch('message',{source,data:{type:'SKIP_WAITING'}});assert.equal(e.skips.length,0);await e.dispatch('message',{source,data:{type:'PLAYING',value:false}});assert.equal(e.skips.length,1);});
+test('reported playback defers explicit activation until pause; install never calls skipWaiting',async()=>{const e=environment(),source={id:'p'};await e.dispatch('message',{data:{type:'SKIP_WAITING'}});assert.equal(e.skips.length,0);await e.dispatch('message',{source,data:{type:'PLAYING',value:true}});await e.dispatch('message',{source,data:{type:'SKIP_WAITING'}});assert.equal(e.skips.length,0);await e.dispatch('message',{source,data:{type:'PLAYING',value:false}});assert.equal(e.skips.length,1);});

frontend/sw-update.js

@@ -1,7 +1,7 @@
 /* ============================================================================
  * sw-update — makes "Refresh UI" actually land the new build.
  *
- * Framework-free and dependency-free on purpose (same pattern as
+ * Framework-free, with a shared sync core and a legacy fallback (same pattern as
  * async-guard.js):
  *   • Loads as a plain <script> under CSP `script-src 'self'` (browser
  *     global `window.SwUpdate`).
@@ -17,7 +17,7 @@
  * already current (a failed install leaves a partial cache that the
  * activate handler then mistook for a previous deploy).
  *
- * The fix no longer depends on the service-worker install lifecycle:
+ * Legacy fallback (retained for ASSET_SYNC=0):
  *   1. refreshShellInPlace() downloads a fresh copy of every file the shell
  *      caches hold (cache-busted, so even an old worker's cache-first
  *      handler can't answer with the stale copy) — ALL of them or nothing —
@@ -25,6 +25,10 @@
  *      serves the next load, it serves the new build.
  *   2. Only then is a waiting worker (if any) activated, and the page
  *      reloaded once.
+ * Incremental mode uses AssetSyncCore to fetch only missing verified hash URLs
+ * and publishes a complete blocking set. Playback guards cover activation and
+ * reload callbacks; PLAYING reports provide an additional worker guard.
+ *
  * The banner itself only opens when the build the page is running differs
  * from the server's (see app.js maybeShowUpdateBanner), so no lifecycle
  * event can re-open it once the page is current.

frontend/sw-update.test.js

@@ -356,3 +356,9 @@ test('playback guard blocks activation and reload unless explicit override is ac
  assert.equal(messages.length,0);assert.equal(reloads,0);
  let playing=false;const container=fakeContainer();await applyUpdate({reg,container,reload:()=>reloads++,isPlaying:()=>playing,askStatus:async()=>({ready:true}),setTimeout:()=>{}});playing=true;container.fireControllerChange();assert.equal(reloads,0);
 });
+test('explicit playback override clears the worker guard and reloads once',async()=>{
+ const messages=[];let reloads=0;const container=fakeContainer();
+ await applyUpdate({reg:{waiting:{postMessage:m=>messages.push(m)}},container,reload:()=>reloads++,isPlaying:()=>true,confirmOverride:()=>true,askStatus:async()=>({ready:true}),setTimeout:()=>{}});
+ assert.deepStrictEqual(messages,[{type:'PLAYING',value:false},{type:'SKIP_WAITING'}]);
+ container.fireControllerChange();container.fireControllerChange();assert.equal(reloads,1);
+});

frontend/sw.js

@@ -2,7 +2,7 @@
  * sw.js — YT Player Service Worker
  *
  * Strategy:
- *   App shell (HTML/CSS/JS)    → cache-first, versioned cache
+ *   App shell (HTML/CSS/JS)    → cache-first, exact per-file hash keys
  *   /api/* requests            → network-only (never cache yt-dlp results)
  *   /api/download/*            → network-only (streamed binary, never cache)
  *   YouTube thumbnails (i.ytimg.com) → stale-while-revalidate
@@ -14,9 +14,9 @@
  *   2. The client (app.js) shows the "Update available" banner only when the
  *      build it is running differs from the server's /api/version buildTag —
  *      a waiting worker or a broadcast is merely a prompt to re-check.
- *   3. "Refresh UI" (sw-update.js) re-downloads every shell file into every
- *      versioned shell cache (all-or-nothing), activates a waiting worker if
- *      there is one (SKIP_WAITING), and reloads once.
+ *   3. Install syncs missing assets into ytplayer-assets. "Refresh UI" activates
+ *      the verified waiting worker (SKIP_WAITING) and reloads once. The legacy
+ *      full-shell path remains available through ASSET_SYNC=0.
  *   4. activate: if an older *versioned shell cache* is found (i.e. this
  *      activation is genuinely replacing a previous deploy, not just the
  *      first-ever install of a freshly (re)registered worker), broadcast
@@ -292,7 +292,7 @@ self.addEventListener('message', (e) => {
     playingClients.set(e.source.id, !!e.data.value);
     if (!e.data.value && deferredClients.delete(e.source.id)) self.skipWaiting();
   }
-  if (e.data && e.data.type === 'SKIP_WAITING') {
+  if (e.data && e.data.type === 'SKIP_WAITING' && e.source && e.source.id) {
     const id = e.source && e.source.id;
     if (playingClients.get(id)) deferredClients.add(id);
     else self.skipWaiting();