fix: restore per-batch helper, then remove the need for helpers entirely

mods/features/adblock.js

@@ -529,48 +529,35 @@ function filterContinuationItems(items, pageName, hasContinuation = false, label
   clearKeepOneMarkers(items, label);
   let filteredItems = hideVideo(items, pageName);
   filteredItems = filterShortsFromItems(filteredItems, pageName);
+  // Every all-watched batch keeps its OWN helper. Do not try to reuse a single
+  // helper across batches and return [] for the rest — that was tried and it
+  // stops the playlist loading dead:
+  //
+  //   keep-one.register  BO7rZs_CYQs
+  //   keep-one.reused    active:["BO7rZs_CYQs"]
+  //   continuation.detected  x1   <- and nothing further, ever
+  //
+  // A 68-video playlist got two batches in and stalled showing only the helper.
+  // Confirmed deliberately: video 68 was set to 20% watched against an 80% hide
+  // threshold so it had to render, and it never appeared, because batch 5 was
+  // never fetched.
+  //
+  // YouTube's refill loop needs each continuation response to append at least
+  // one item. Hand it an empty batch and it treats the fetch as satisfied and
+  // stops asking, so the chain dies at the last non-empty response. The
+  // per-batch helper is what keeps that loop alive — the list stays starved
+  // enough to request more while still receiving something each time. The
+  // stranded blank slots are the price, and the data model that would let us
+  // clean them up is unreachable on Tizen 5.0 (654577e).
   if (pageName === 'playlist' && hasContinuation && filteredItems.length === 0 && Array.isArray(items) && items.length > 0) {
     const reverseItems = [...items].reverse();
     const fallbackItem =
       reverseItems.find(item => item?.tileRenderer?.header?.tileHeaderRenderer?.thumbnail?.thumbnails?.length) ||
       reverseItems.find(item => item?.tileRenderer) || items[items.length - 1];
-    // Cap the playlist at ONE helper for the whole visit.
-    //
-    // A helper exists so the list is never left empty, because an empty list
-    // is what makes YouTube TV reload the page. It does NOT need to be a fresh
-    // one per batch: an all-watched 68-video playlist was measured keeping one
-    // helper per response — four blank slots, each permanently stranded in the
-    // virtual list's data model, which is unreachable on Tizen 5.0 (654577e).
-    //
-    // Keeping the existing helper instead is safe because the list stays
-    // non-empty either way, and it is sufficient because YouTube drives the
-    // remaining batches itself. That was confirmed by disabling our own
-    // schedulePlaylistAutoLoad cascade entirely (autoload_skipped x3) and
-    // watching YouTube still pull the whole playlist in 780ms unaided
-    // — 18:44:01.022, .239, .455 — purely because filtering leaves the
-    // viewport starved. So dropping the extra helpers costs no loading.
-    // Scoped to this playlist. The helper sets live on window and are only
-    // wiped when a !hasContinuation response arrives, so navigating away
-    // mid-load leaves them populated — reusing one of those on the NEXT
-    // playlist would mean never keeping a helper there, leaving its list
-    // empty, which is the exact condition that makes YouTube TV reload the
-    // page. Tie the reuse to the hash the helper was created under.
-    const playlistKey = String(window.location?.hash || '');
-    const helperKeyMatches = window.__ttHelperPlaylistKey === playlistKey;
-    const existingHelper = helperKeyMatches &&
-      (getPlaylistHelperVideoIdSet().size > 0 || getRetiredPlaylistHelperVideoIdSet().size > 0);
-    if (existingHelper) {
-      appendFileOnlyLog(`${label}.keep-one.reused`, {
-        active: Array.from(getPlaylistHelperVideoIdSet()),
-        retired: getRetiredPlaylistHelperVideoIdSet().size,
-      });
-      return [];
-    }
     if (fallbackItem && typeof fallbackItem === 'object') {
       fallbackItem.__ttKeepOneForContinuation = true;
       fallbackItem.__ttKeepOneForContinuationLabel = `${label}.visible`;
       fallbackItem.__ttKeepOneForContinuationParseSeq = Number(window.__ttParseSeq || 0);
-      window.__ttHelperPlaylistKey = playlistKey;
       registerPlaylistHelperVideoId(getItemVideoId(fallbackItem), `${label}.keep-one`);
     }
     // All items in this batch are watched — auto-fetch the next batch without waiting
@@ -594,21 +581,6 @@ function filterContinuationItems(items, pageName, hasContinuation = false, label
 
 function filterPlaylistRendererContents(playlistRenderer, pageName, label = 'playlist.renderer') {
   if (!playlistRenderer || !Array.isArray(playlistRenderer.contents)) return;
-  if (pageName === 'playlist') {
-    // A page-level playlist response means a freshly rendered list, so no
-    // helper from an earlier visit can still be on screen. Reset the one-per-
-    // playlist cap here: the sets live on window and are otherwise only wiped
-    // by a !hasContinuation response, so leaving a playlist mid-load would
-    // strand them — and a stranded set would make the cap skip creating this
-    // playlist's own helper, leaving the list empty, which is what makes
-    // YouTube TV reload the page. Also covers the page "restart" 654577e
-    // documented, where stale retired ids caused the observer to strip
-    // freshly rendered tiles.
-    getPlaylistHelperVideoIdSet().clear();
-    getRetiredPlaylistHelperVideoIdSet().clear();
-    window.__ttHelperPlaylistKey = null;
-    updateAllHelperHideStyles();
-  }
   const hasContinuation = !!playlistRenderer?.continuations;
   const before = playlistRenderer.contents.length;
   playlistRenderer.contents = filterContinuationItems(playlistRenderer.contents, pageName, hasContinuation, label);