Fix 'literal string will be frozen in the future' warnings with ruby 3.4

Author: BenTalagan

Gemfile

@@ -2,6 +2,7 @@
 
 source "https://rubygems.org"
 
+
 group :development do
   # excludes Windows, Rubinius and JRuby
   gem "ruby-prof", :platforms => [:mri_19, :mri_20, :mri_21]
@@ -13,6 +14,7 @@ group :test do
   gem "rspec", ">= 3.8.0"
   gem "rspec-its"
   gem "simplecov"
+  gem 'bigdecimal'
 end
 
 group :development, :test do

codegen/protocol.rb.pytemplate

@@ -1,5 +1,6 @@
 # encoding: utf-8
 # encoding: binary
+# frozen_string_literal: true
 
 # THIS IS AN AUTOGENERATED FILE, DO NOT MODIFY
 # IT DIRECTLY ! FOR CHANGES, PLEASE UPDATE FILES
@@ -142,7 +143,7 @@ module AMQ
       % for f in klass.fields:
       # <% i = klass.fields.index(f) %>1 << ${15 - i}
       def self.encode_${f.ruby_name}(value)
-        buffer = ''
+        buffer = +''
         % for line in helpers.genSingleEncode(spec, "value", f.domain):
         ${line}
         % endfor

lib/amq/protocol/client.rb

@@ -1,4 +1,5 @@
 # encoding: binary
+# frozen_string_literal: true
 
 # THIS IS AN AUTOGENERATED FILE, DO NOT MODIFY
 # IT DIRECTLY ! FOR CHANGES, PLEASE UPDATE FILES
@@ -1389,107 +1390,107 @@ class Basic < Protocol::Class
 
       # 1 << 15
       def self.encode_content_type(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [0, 0x8000, buffer]
       end
 
       # 1 << 14
       def self.encode_content_encoding(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [1, 0x4000, buffer]
       end
 
       # 1 << 13
       def self.encode_headers(value)
-        buffer = ''
+        buffer = +''
         buffer << AMQ::Protocol::Table.encode(value)
         [2, 0x2000, buffer]
       end
 
       # 1 << 12
       def self.encode_delivery_mode(value)
-        buffer = ''
+        buffer = +''
         buffer << [value].pack(PACK_CHAR)
         [3, 0x1000, buffer]
       end
 
       # 1 << 11
       def self.encode_priority(value)
-        buffer = ''
+        buffer = +''
         buffer << [value].pack(PACK_CHAR)
         [4, 0x0800, buffer]
       end
 
       # 1 << 10
       def self.encode_correlation_id(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [5, 0x0400, buffer]
       end
 
       # 1 << 9
       def self.encode_reply_to(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [6, 0x0200, buffer]
       end
 
       # 1 << 8
       def self.encode_expiration(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [7, 0x0100, buffer]
       end
 
       # 1 << 7
       def self.encode_message_id(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [8, 0x0080, buffer]
       end
 
       # 1 << 6
       def self.encode_timestamp(value)
-        buffer = ''
+        buffer = +''
         buffer << AMQ::Pack.pack_uint64_big_endian(value)
         [9, 0x0040, buffer]
       end
 
       # 1 << 5
       def self.encode_type(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [10, 0x0020, buffer]
       end
 
       # 1 << 4
       def self.encode_user_id(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [11, 0x0010, buffer]
       end
 
       # 1 << 3
       def self.encode_app_id(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [12, 0x0008, buffer]
       end
 
       # 1 << 2
       def self.encode_cluster_id(value)
-        buffer = ''
+        buffer = +''
         buffer << value.to_s.bytesize.chr
         buffer << value.to_s
         [13, 0x0004, buffer]

spec/amq/protocol/table_spec.rb

@@ -1,4 +1,3 @@
-require 'bigdecimal'
 require 'time'
 
 module AMQ