Apply yield forcely

src/library/title.cr

@@ -115,6 +115,7 @@ class Title
     previous_entries_size = @entries.size
     @entries.select! do |entry|
       existence = File.exists? entry.zip_path
+      yield_process_file context
       context["deleted_entry_ids"] << entry.id unless existence
       existence
     end

src/library/types.cr

@@ -140,3 +140,8 @@ alias ExamineContext = NamedTuple(
   deleted_title_ids: Array(String),
   deleted_entry_ids: Array(String)
 )
+
+def yield_process_file(context : ExamineContext)
+  context["file_count"] += 1
+  Fiber.yield if context["file_count"] % 1000 == 0
+end

src/util/signature.cr

@@ -56,6 +56,7 @@ class Dir
   #       directories)
   def self.contents_signature(dirname, cache = {} of String => String) : String
     return cache[dirname] if !cache.nil? && cache[dirname]?
+    Fiber.yield # Yield first
     signatures = [] of String
     self.open dirname do |dir|
       dir.entries.sort.each do |fn|