perf: avoid creating an extra list when iterating through values or keys

lib/fluent/config/configure_proxy.rb

@@ -201,7 +201,7 @@ def merge_for_finalized(other)
 
       def overwrite_defaults(other) # other is owner plugin's corresponding proxy
         self.defaults = self.defaults.merge(other.defaults)
-        self.sections.keys.each do |section_key|
+        self.sections.each_key do |section_key|
           if other.sections.has_key?(section_key)
             self.sections[section_key].overwrite_defaults(other.sections[section_key])
           end

lib/fluent/configurable.rb

@@ -31,13 +31,13 @@ def initialize
       super
       # to simulate implicit 'attr_accessor' by config_param / config_section and its value by config_set_default
       proxy = self.class.merged_configure_proxy
-      proxy.params.keys.each do |name|
+      proxy.params.each_key do |name|
         next if name.to_s.start_with?('@')
         if proxy.defaults.has_key?(name)
           instance_variable_set("@#{name}".to_sym, proxy.defaults[name])
         end
       end
-      proxy.sections.keys.each do |name|
+      proxy.sections.each_key do |name|
         next if name.to_s.start_with?('@')
         subproxy = proxy.sections[name]
         if subproxy.multi?

lib/fluent/counter/mutex_hash.rb

@@ -54,7 +54,7 @@ def synchronize(*keys)
               if mutex.try_lock
                 locks[key] = mutex
               else
-                locks.values.each(&:unlock)
+                locks.each_value(&:unlock)
                 locks = {}          # flush locked keys
                 break
               end

lib/fluent/log.rb

@@ -584,7 +584,7 @@ def event(level, args)
 
       if @log_event_enabled && !@threads_exclude_events.include?(Thread.current)
         record = map.dup
-        record.keys.each {|key|
+        record.each_key {|key|
           record[key] = record[key].inspect unless record[key].respond_to?(:to_msgpack)
         }
         record['message'] = message.dup

lib/fluent/plugin/in_tail.rb

@@ -488,7 +488,7 @@ def stop_watchers(targets_info, immediate: false, unwatched: false, remove_watch
     end
 
     def close_watcher_handles
-      @tails.keys.each do |path|
+      @tails.each_key do |path|
         tw = @tails.delete(path)
         if tw
           tw.close

lib/fluent/plugin/parser.rb

@@ -43,7 +43,7 @@ def start
             until @flag.wait_for_set(0.5)
               now = Time.now
               @mutex.synchronize {
-                @map.keys.each { |th|
+                @map.each_key { |th|
                   time = @map[th]
                   if now - time > @timeout
                     th.raise UncatchableError, "parsing timed out"

lib/fluent/test/driver/base.rb

@@ -87,7 +87,7 @@ def run(timeout: nil, start: true, shutdown: true, &block)
 
           sleep_with_watching_threads = ->(){
             if @instance.respond_to?(:_threads)
-              @instance._threads.values.each{|t| t.join(0) }
+              @instance._threads.each_value{|t| t.join(0) }
             end
             sleep 0.1
           }

lib/fluent/test/output_test.rb

@@ -139,7 +139,7 @@ def run(&block)
             assert_equal(@expected_buffer, buffer)
           end
 
-          lines.keys.each do |meta|
+          lines.each_key do |meta|
             chunk = @instance.buffer.generate_chunk(meta).staged!
             chunk.append(lines[meta])
             begin