Suppress 'warning: literal string will be frozen in the future'

Signed-off-by: Watson <watson1978@gmail.com>

Author: Watson1978

lib/fluent/command/ctl.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #
@@ -67,7 +69,7 @@ def initialize(argv = ARGV)
     end
 
     def help_text
-      text = "\n"
+      text = +"\n"
       if Fluent.windows?
         text << "Usage: #{$PROGRAM_NAME} COMMAND [PID_OR_SVCNAME]\n"
       else

lib/fluent/command/plugin_config_formatter.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #
@@ -79,7 +81,7 @@ def call
   private
 
   def dump_txt(dumped_config)
-    dumped = ""
+    dumped = +""
     plugin_helpers = dumped_config.delete(:plugin_helpers)
     if plugin_helpers && !plugin_helpers.empty?
       dumped << "helpers: #{plugin_helpers.join(',')}\n"
@@ -101,7 +103,7 @@ def dump_txt(dumped_config)
   end
 
   def dump_section_txt(base_section, level = 0)
-    dumped = ""
+    dumped = +""
     indent = " " * level
     if base_section[:section]
       sections = []
@@ -135,10 +137,10 @@ def dump_section_txt(base_section, level = 0)
   end
 
   def dump_markdown(dumped_config)
-    dumped = ""
+    dumped = +""
     plugin_helpers = dumped_config.delete(:plugin_helpers)
     if plugin_helpers && !plugin_helpers.empty?
-      dumped = "## Plugin helpers\n\n"
+      dumped = +"## Plugin helpers\n\n"
       plugin_helpers.each do |plugin_helper|
         dumped << "* #{plugin_helper_markdown_link(plugin_helper)}\n"
       end
@@ -156,7 +158,7 @@ def dump_markdown(dumped_config)
   end
 
   def dump_section_markdown(base_section, level = 0)
-    dumped = ""
+    dumped = +""
     if base_section[:section]
       sections = []
       params = base_section

lib/fluent/compat/formatter_utils.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #

lib/fluent/compat/output.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #

lib/fluent/compat/record_filter_mixin.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #
@@ -21,7 +23,7 @@ def filter_record(tag, time, record)
       end
 
       def format_stream(tag, es)
-        out = ''
+        out = +''
         es.each {|time,record|
           tag_temp = tag.dup
           filter_record(tag_temp, time, record)

lib/fluent/config/element.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #
@@ -141,7 +143,7 @@ def check_not_fetched(&block)
       def to_s(nest = 0)
         indent = "  " * nest
         nindent = "  " * (nest + 1)
-        out = ""
+        out = +""
         if @arg.nil? || @arg.empty?
           out << "#{indent}<#{@name}>\n"
         else
@@ -230,7 +232,7 @@ def dump_value(k, v, nindent)
       end
 
       def self.unescape_parameter(v)
-        result = ''
+        result = +''
         v.each_char { |c| result << LiteralParser.unescape_char(c) }
         result
       end

lib/fluent/config/literal_parser.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #
@@ -228,8 +230,8 @@ def scan_json(is_array)
         # Yajl does not raise ParseError for incomplete json string, like '[1', '{"h"', '{"h":' or '{"h1":1'
         # This is the reason to use JSON module.
 
-        buffer = (is_array ? "[" : "{")
-        line_buffer = ""
+        buffer = +(is_array ? "[" : "{")
+        line_buffer = +""
 
         until result
           char = getch
@@ -252,7 +254,7 @@ def scan_json(is_array)
                 # ignore comment char
               end
               buffer << line_buffer + "\n"
-              line_buffer = ""
+              line_buffer = +""
             else
               # '#' is a char in json string
               line_buffer << char
@@ -263,7 +265,7 @@ def scan_json(is_array)
 
           if char == "\n"
             buffer << line_buffer + "\n"
-            line_buffer = ""
+            line_buffer = +""
             next
           end
 

lib/fluent/config/types.rb

@@ -183,7 +183,7 @@ def self.enum_value(val, opts = {}, name = nil)
         value
       else
         case type
-        when :string  then value.to_s.force_encoding(Encoding::UTF_8)
+        when :string  then (+(value.to_s)).force_encoding(Encoding::UTF_8)
         when :integer then INTEGER_TYPE.call(value, opts, name)
         when :float   then FLOAT_TYPE.call(value, opts, name)
         when :size then Config.size_value(value, opts, name)

lib/fluent/config/yaml_parser/fluent_value.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #
@@ -30,7 +32,7 @@ def to_element
 
         StringValue = Struct.new(:val, :context) do
           def to_s
-            context.instance_eval("\"#{val}\"")
+            context.instance_eval("\"#{val}\"").freeze
           rescue Fluent::SetNil => _
             ''
           rescue Fluent::SetDefault => _

lib/fluent/log.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 #
 # Fluentd
 #
@@ -205,7 +207,7 @@ def format=(fmt)
         @format = :text
         @formatter = Proc.new { |type, time, level, msg|
           r = caller_line(type, time, @depth_offset, level)
-          r << msg
+          r += msg
           r
         }
       when :json
@@ -550,7 +552,7 @@ def get_worker_id(type)
 
     def event(level, args)
       time = Time.now
-      message = @optional_header ? @optional_header.dup : ''
+      message = @optional_header ? @optional_header.dup : +''
       map = @optional_attrs ? @optional_attrs.dup : {}
       args.each {|a|
         if a.is_a?(Hash)