Fix batch importing of channels

src/invidious/channels.cr

@@ -23,28 +23,39 @@ struct ChannelVideo
 end
 
 def get_batch_channels(channels, db, refresh = false, pull_all_videos = true, max_threads = 10)
-  active_threads = 0
+  finished_channel = Channel(String | Nil).new
-  active_channel = Channel(String | Nil).new
 
-  final = [] of String
+  spawn do
-  channels.map do |ucid|
+    active_threads = 0
+    active_channel = Channel(Nil).new
+
+    channels.each do |ucid|
       if active_threads >= max_threads
-      if response = active_channel.receive
+        active_channel.receive
         active_threads -= 1
-        final << response
-      end
       end
 
       active_threads += 1
       spawn do
         begin
           get_channel(ucid, db, refresh, pull_all_videos)
-        active_channel.send(ucid)
+          finished_channel.send(ucid)
         rescue ex
+          finished_channel.send(nil)
+        ensure
           active_channel.send(nil)
         end
       end
     end
+  end
+
+  final = [] of String
+  channels.size.times do
+    ucid = finished_channel.receive
+    if ucid
+      final << ucid
+    end
+  end
 
   return final
 end