Guard stale app execution against feature contract changes

frontend/app-bootstrap.js

@@ -42,7 +42,8 @@
       const previousKey=state && root.AssetSyncCore.fallback(manifest,state.previous,'/app.js');
       const previous=previousKey && await cache.match(previousKey);
       const previousHash=state?.previous?.files['/app.js']?.h;
-      if(root.navigator?.serviceWorker?.controller && previous?.ok && previous.headers.get('X-Asset-Hash')===previousHash) {
+      const contractsMatch=state?.previous && Object.entries(manifest.groups).every(([name,group])=>state.previous.groups[name]?.contract===group.contract);
+      if(contractsMatch && root.navigator?.serviceWorker?.controller && previous?.ok && previous.headers.get('X-Asset-Hash')===previousHash) {
         await verified(previous,previousHash);
         delete root.Lazy.appResponse;
         return external(previousKey);

frontend/app-bootstrap.test.js

@@ -54,3 +54,10 @@ test('missing current app uses verified same-contract N-1 offline through the co
 test('an incompatible previous core never executes against the new shell',async()=>{
  const f=fixture({previous:true,contract:2});await assert.rejects(f.root.AppBootstrap.ready,/hash/);assert.equal(f.root.appRuns,undefined);
 });
+
+
+test('a feature contract change also prevents stale core execution',async()=>{
+ const f=fixture({previous:true});f.root.Lazy.manifest.groups['feature:test']={contract:2,files:[]};
+ const state=await f.held.get('/__ytp_asset_state').json();state.previous.groups['feature:test']={contract:1,files:[]};f.held.set('/__ytp_asset_state',Response.json(state));
+ await assert.rejects(f.root.AppBootstrap.ready,/hash/);assert.equal(f.root.appRuns,undefined);
+});

perf/README.md

@@ -350,3 +350,7 @@ then use the page FCP to locate the rendering dependency.
 Pass `--assert-cold` on new builds to require exactly one positive-byte app.js
 response in every cold sample, including worker installation. Omit this assertion
 when diagnosing historical regressions.
+
+Phase 6 counts its fetch-owned app.js response in initial JS/CSS bytes. Since the
+bootstrap consumes that response asynchronously, DOMContentLoaded no longer means
+app execution is complete; compare the existing actual boot-done landmark.

perf/baseline.mjs

@@ -377,8 +377,8 @@ async function runColdScenario({ browserType, server, proxy, profile }) {
     const fcp = paint.find((p) => p.name === 'first-contentful-paint');
 
     return {
-      initialJsCss: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&['script','link','css'].includes(entry.initiatorType)).reduce((sum,entry)=>sum+entry.encodedBodySize,0),
+      initialJsCss: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&(['script','link','css'].includes(entry.initiatorType)||(entry.initiatorType==='fetch'&&new URL(entry.name).pathname==='/app.js'))).reduce((sum,entry)=>sum+entry.encodedBodySize,0),
-      initialAssetRequests: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&['script','link','css'].includes(entry.initiatorType)).map(entry=>({url:entry.name,bytes:entry.encodedBodySize,start:entry.startTime,responseStart:entry.responseStart,end:entry.responseEnd,initiator:entry.initiatorType})),
+      initialAssetRequests: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&(['script','link','css'].includes(entry.initiatorType)||(entry.initiatorType==='fetch'&&new URL(entry.name).pathname==='/app.js'))).map(entry=>({url:entry.name,bytes:entry.encodedBodySize,start:entry.startTime,responseStart:entry.responseStart,end:entry.responseEnd,initiator:entry.initiatorType})),
       fcp: fcp ? Math.round(fcp.startTime) : null,
       lcp: window.__lcp ? Math.round(window.__lcp) : null,
       domContentLoaded: nav ? Math.round(nav.domContentLoadedEventEnd - nav.startTime) : null,
@@ -486,8 +486,8 @@ async function runWarmScenario({ browserType, server, proxy, profile }) {
     const fcp = paint.find((p) => p.name === 'first-contentful-paint');
 
     return {
-      initialJsCss: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&['script','link','css'].includes(entry.initiatorType)).reduce((sum,entry)=>sum+entry.encodedBodySize,0),
+      initialJsCss: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&(['script','link','css'].includes(entry.initiatorType)||(entry.initiatorType==='fetch'&&new URL(entry.name).pathname==='/app.js'))).reduce((sum,entry)=>sum+entry.encodedBodySize,0),
-      initialAssetRequests: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&['script','link','css'].includes(entry.initiatorType)).map(entry=>({url:entry.name,bytes:entry.encodedBodySize,start:entry.startTime,responseStart:entry.responseStart,end:entry.responseEnd,initiator:entry.initiatorType})),
+      initialAssetRequests: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&(['script','link','css'].includes(entry.initiatorType)||(entry.initiatorType==='fetch'&&new URL(entry.name).pathname==='/app.js'))).map(entry=>({url:entry.name,bytes:entry.encodedBodySize,start:entry.startTime,responseStart:entry.responseStart,end:entry.responseEnd,initiator:entry.initiatorType})),
       fcp: fcp ? Math.round(fcp.startTime) : null,
       lcp: window.__lcp ? Math.round(window.__lcp) : null,
       domContentLoaded: nav ? Math.round(nav.domContentLoadedEventEnd - nav.startTime) : null,
@@ -567,8 +567,8 @@ async function runOfflineScenario({ browserType, server, proxy, profile }) {
     const fcp = paint.find((p) => p.name === 'first-contentful-paint');
 
     return {
-      initialJsCss: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&['script','link','css'].includes(entry.initiatorType)).reduce((sum,entry)=>sum+entry.encodedBodySize,0),
+      initialJsCss: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&(['script','link','css'].includes(entry.initiatorType)||(entry.initiatorType==='fetch'&&new URL(entry.name).pathname==='/app.js'))).reduce((sum,entry)=>sum+entry.encodedBodySize,0),
-      initialAssetRequests: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&['script','link','css'].includes(entry.initiatorType)).map(entry=>({url:entry.name,bytes:entry.encodedBodySize,start:entry.startTime,responseStart:entry.responseStart,end:entry.responseEnd,initiator:entry.initiatorType})),
+      initialAssetRequests: performance.getEntriesByType('resource').filter(entry=>/\.(?:js|css)(?:[?#]|$)/.test(entry.name)&&entry.startTime <= nav.domContentLoadedEventEnd&&(['script','link','css'].includes(entry.initiatorType)||(entry.initiatorType==='fetch'&&new URL(entry.name).pathname==='/app.js'))).map(entry=>({url:entry.name,bytes:entry.encodedBodySize,start:entry.startTime,responseStart:entry.responseStart,end:entry.responseEnd,initiator:entry.initiatorType})),
       fcp: fcp ? Math.round(fcp.startTime) : null,
       lcp: window.__lcp ? Math.round(window.__lcp) : null,
       domContentLoaded: nav ? Math.round(nav.domContentLoadedEventEnd - nav.startTime) : null,

perf/lazy.mjs

@@ -84,6 +84,23 @@ async function run(name){
   await page.evaluate(async()=>{await Lazy.load('feature:export');await Lazy.load('feature:video-edit');});
   assert.equal(proxy.getStats().requestCount,before,'all warmed extension assets stay offline');
   await start();disconnected=false;await proxy.setOffline(false);await page.evaluate(()=>localStorage.removeItem('perf-offline')); 
+  // Change only app bytes, then prove loss of its current cache entry can boot
+  // the compatible N-1 core offline without weakening the inline CSP policy.
+  await stop();writeFileSync(join(cwd,'public/app.js'),readFileSync(join(cwd,'public/app.js'),'utf8')+'\n// phase6 app eviction probe\n');await start();
+  const appTarget=await(await fetch(origin+'/api/manifest')).json();
+  await page.evaluate(async()=>{const r=await navigator.serviceWorker.getRegistration();await r.update();});
+  await wait(page,async tag=>{const r=await navigator.serviceWorker.getRegistration();return r?.waiting&&(await SwUpdate.askCacheStatus(r.waiting))?.version===tag;},appTarget.buildTag);
+  await page.evaluate(async()=>{const r=await navigator.serviceWorker.getRegistration();r.waiting.postMessage({type:'SKIP_WAITING'});});
+  await wait(page,async tag=>{const c=await caches.open('ytplayer-assets');return(await(await c.match('/__ytp_asset_state')).json()).current.buildTag===tag;},appTarget.buildTag);
+  const appKey='/app.js?v='+appTarget.files['/app.js'].h;
+  await page.evaluate(async key=>{await(await caches.open('ytplayer-assets')).delete(key);},appKey);
+  await stop();disconnected=true;await proxy.setOffline(true);
+  const probe=await context.newPage();probe.on('pageerror',e=>errors.push({message:e.message,disconnected}));
+  const offlineBefore=proxy.getStats().requestCount;await probe.goto(origin);await probe.waitForFunction(()=>typeof data!=='undefined'&&typeof Player!=='undefined'&&document.querySelector('#carModeBtn'));
+  assert.equal(await probe.evaluate(async key=>!!await(await caches.open('ytplayer-assets')).match(key),appKey),false,'N-1 never poisons the current app key');
+  assert.equal(proxy.getStats().requestCount,offlineBefore,'N-1 app boot is entirely offline');
+  await probe.close();await start();disconnected=false;await proxy.setOffline(false);
+  await page.evaluate(async key=>{const r=await fetch(key+'&__ytpfresh=1');if(r.headers.get('X-Asset-Hash')!==key.split('v=')[1])throw Error('Wrong repair body');await(await caches.open('ytplayer-assets')).put(key,r);},appKey);
   // Keep an old tab whose core and group contracts remain those of build N.
   const old=await context.newPage();old.on('pageerror',e=>errors.push({message:e.message,disconnected}));await old.goto(origin);await old.waitForSelector('#carModeBtn');
   await old.evaluate(async()=>{window.__saveData=true;await Lazy.load('feature:setlist-import');window.__pinned=window.SetlistImport;});
@@ -128,7 +145,7 @@ async function run(name){
   const offlineTransportErrors=errors.filter(error=>name==='webkit'&&error.disconnected&&(error.message==='TypeError: Load failed'||/\/api\/(?:recommendations\?[^\s]*|version)\.$/.test(error.message)));
   assert.deepEqual(errors.filter(error=>!offlineTransportErrors.includes(error)),[]);
   if(offlineTransportErrors.length)assert.ok(failedRequests.some(url=>/\/api\/(?:recommendations|version)/.test(url))); 
-  results.push({browser:name,sourceBuildTag:previous.buildTag,classicSharedDefaults:true,cssOrderPreserved:true,settingsSearch:true,carControls:4,offlineFeature:true,firstUseNetwork:0,layoutsOffline:['glass-stage','bento-hub','f7-swipe','classic'],pinned:true,compatibleUnexecutedNewURL:true,incompatibleN1ReloadRequired:true,stagedN1:true,playbackGuard:true,prePaintLayout:true,offlineSettingsPanels:true,scriptErrors:[],offlineTransportErrors});
+  results.push({browser:name,sourceBuildTag:previous.buildTag,classicSharedDefaults:true,cssOrderPreserved:true,settingsSearch:true,carControls:4,offlineFeature:true,firstUseNetwork:0,layoutsOffline:['glass-stage','bento-hub','f7-swipe','classic'],pinned:true,compatibleUnexecutedNewURL:true,incompatibleN1ReloadRequired:true,stagedN1:true,appEvictionN1Offline:true,playbackGuard:true,prePaintLayout:true,offlineSettingsPanels:true,scriptErrors:[],offlineTransportErrors});
   console.log(name,'PASS');
  } finally {await browser?.close();await proxy?.close();await stop();}
 }

perf/results/phase6-lazy-2026-10-08.json

@@ -0,0 +1,97 @@
+{
+  "results": [
+    {
+      "browser": "chromium",
+      "sourceBuildTag": "41a7ba2c29a3",
+      "classicSharedDefaults": true,
+      "cssOrderPreserved": true,
+      "settingsSearch": true,
+      "carControls": 4,
+      "offlineFeature": true,
+      "firstUseNetwork": 0,
+      "layoutsOffline": [
+        "glass-stage",
+        "bento-hub",
+        "f7-swipe",
+        "classic"
+      ],
+      "pinned": true,
+      "compatibleUnexecutedNewURL": true,
+      "incompatibleN1ReloadRequired": true,
+      "stagedN1": true,
+      "appEvictionN1Offline": true,
+      "playbackGuard": true,
+      "prePaintLayout": true,
+      "offlineSettingsPanels": true,
+      "scriptErrors": [],
+      "offlineTransportErrors": []
+    },
+    {
+      "browser": "webkit",
+      "sourceBuildTag": "41a7ba2c29a3",
+      "classicSharedDefaults": true,
+      "cssOrderPreserved": true,
+      "settingsSearch": true,
+      "carControls": 4,
+      "offlineFeature": true,
+      "firstUseNetwork": 0,
+      "layoutsOffline": [
+        "glass-stage",
+        "bento-hub",
+        "f7-swipe",
+        "classic"
+      ],
+      "pinned": true,
+      "compatibleUnexecutedNewURL": true,
+      "incompatibleN1ReloadRequired": true,
+      "stagedN1": true,
+      "appEvictionN1Offline": true,
+      "playbackGuard": true,
+      "prePaintLayout": true,
+      "offlineSettingsPanels": true,
+      "scriptErrors": [],
+      "offlineTransportErrors": [
+        {
+          "message": "TypeError: Load failed",
+          "disconnected": true
+        },
+        {
+          "message": "/127.0.0.1:36117/api/version.",
+          "disconnected": true
+        },
+        {
+          "message": "TypeError: Load failed",
+          "disconnected": true
+        },
+        {
+          "message": "/127.0.0.1:36117/api/recommendations?fp=163577c02a53bc40.",
+          "disconnected": true
+        },
+        {
+          "message": "TypeError: Load failed",
+          "disconnected": true
+        },
+        {
+          "message": "/127.0.0.1:36117/api/version.",
+          "disconnected": true
+        },
+        {
+          "message": "TypeError: Load failed",
+          "disconnected": true
+        },
+        {
+          "message": "/127.0.0.1:36117/api/recommendations?fp=163577c02a53bc40.",
+          "disconnected": true
+        },
+        {
+          "message": "TypeError: Load failed",
+          "disconnected": true
+        },
+        {
+          "message": "/127.0.0.1:36117/api/version.",
+          "disconnected": true
+        }
+      ]
+    }
+  ]
+}

plans/phase6-investigation.md

@@ -76,3 +76,12 @@ all samples. Full-harness configurations now reset to the base tree before each
 browser/profile, preventing a preceding synthetic update from contaminating the
 next cold build. The historical invalid media fixture remains unchanged: home
 launch only, not autoplay/audio latency.
+
+
+Self-review added explicit N-1 app boot after eviction: verify the retained body
+and use its exact classic URL through the controlling worker. It never fills the
+new key with old bytes. Stale core execution additionally requires every group
+contract to match the running shell's expectations; a core or feature contract
+change rejects it. Both-engine lazy smoke now changes app bytes, evicts the new
+entry, boots N-1 offline, then repairs the current entry before the existing
+feature pinning/contract/playback checks. No source in app.js changed.