Fix StoryIndexService

app/Observers/FollowerObserver.php

@@ -6,6 +6,7 @@ use App\Jobs\HomeFeedPipeline\FeedFollowPipeline;
 use App\Jobs\HomeFeedPipeline\FeedUnfollowPipeline;
 use App\Models\Follower;
 use App\Services\FollowerService;
+use App\Services\StoryIndexService;
 use Illuminate\Support\Facades\Cache;
 
 class FollowerObserver
@@ -22,6 +23,7 @@ class FollowerObserver
         }
 
         FollowerService::add($follower->profile_id, $follower->following_id);
+        app(StoryIndexService::class)->addFollowing($follower->profile_id, $follower->following_id);
         FeedFollowPipeline::dispatch($follower->profile_id, $follower->following_id)->onQueue('follow');
     }
 
@@ -33,6 +35,7 @@ class FollowerObserver
     public function deleted(Follower $follower)
     {
         FollowerService::remove($follower->profile_id, (string) $follower->following_id);
+        app(StoryIndexService::class)->removeFollowing($follower->profile_id, $follower->following_id);
         FeedUnfollowPipeline::dispatch($follower->profile_id, $follower->following_id)->onQueue('feed');
     }
 
@@ -44,5 +47,6 @@ class FollowerObserver
     public function forceDeleted(Follower $follower)
     {
         FollowerService::remove($follower->profile_id, (string) $follower->following_id);
+        app(StoryIndexService::class)->removeFollowing($follower->profile_id, $follower->following_id);
     }
 }

app/Services/StoryIndexService.php

@@ -176,7 +176,16 @@ class StoryIndexService
         $path = $story->path;
 
         Redis::pipeline(function ($pipe) use (
-            $author, $sid, $score, $ttl, $duration, $overlays, $viewCount, $createdIso, $type, $path
+            $author,
+            $sid,
+            $score,
+            $ttl,
+            $duration,
+            $overlays,
+            $viewCount,
+            $createdIso,
+            $type,
+            $path
         ) {
             $keyStory = $this->storyKey($sid);
             $keyAuth = $this->authorKey($author);
@@ -235,6 +244,36 @@ class StoryIndexService
         Redis::expire($key, $finalTtl);
     }
 
+    /**
+     * Keep the cached following set in sync when a follow is created.
+     * Only touches the key if it already exists; otherwise the next carousel
+     * fetch hydrates from SQL and picks up the new follow anyway.
+     */
+    public function addFollowing(int $followerId, int $followingId): void
+    {
+        $key = "following:{$followerId}";
+
+        if (! Redis::exists($key)) {
+            return;
+        }
+
+        Redis::sadd($key, (string) $followingId);
+    }
+
+    /**
+     * Keep the cached following set in sync when a follow is removed.
+     */
+    public function removeFollowing(int $followerId, int $followingId): void
+    {
+        $key = "following:{$followerId}";
+
+        if (! Redis::exists($key)) {
+            return;
+        }
+
+        Redis::srem($key, (string) $followingId);
+    }
+
     public function rebuildIndex(): array
     {
         $lockKey = $this->rebuildLockKey();
@@ -331,7 +370,6 @@ class StoryIndexService
                 'message' => 'Story index and seen data rebuilt successfully',
                 'stats' => $stats,
             ];
-
         } finally {
             Redis::del($lockKey);
         }
@@ -657,7 +695,6 @@ class StoryIndexService
         if (! $hasResults) {
             Redis::pipeline(function ($pipe) use ($followingKey) {
                 $pipe->sadd($followingKey, '__empty__');
-                $pipe->srem($followingKey, '__empty__');
                 $pipe->expire($followingKey, 3600);
             });
         } else {