ruby · jhawthorn · Jun 29, 2026 · Jun 29, 2026 · Jun 29, 2026 · Jun 29, 2026
diff --git a/lib/rexml/cdata.rb b/lib/rexml/cdata.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative "text"
 
 module REXML

diff --git a/lib/rexml/comment.rb b/lib/rexml/comment.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative "child"
 
 module REXML

diff --git a/lib/rexml/doctype.rb b/lib/rexml/doctype.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative "parent"
 require_relative "parseexception"
 require_relative "namespace"
@@ -59,7 +59,7 @@ class DocType < Parent
       'lt'=>EntityConst::LT,
       'quot'=>EntityConst::QUOT,
       "apos"=>EntityConst::APOS
-    }
+    }.freeze
 
     # name is the name of the doctype
     # external_id is the referenced DTD, if given
@@ -183,7 +183,7 @@ def entity( name, expanding: nil )
 
     def add child
       super(child)
-      @entities = DEFAULT_ENTITIES.clone if @entities == DEFAULT_ENTITIES
+      @entities = DEFAULT_ENTITIES.dup if @entities == DEFAULT_ENTITIES
       @entities[ child.name ] = child if child.kind_of? Entity
     end
 
@@ -288,7 +288,7 @@ def initialize name, middle, pub, sys
 
     def to_s
       context = parent&.context
-      notation = "<!NOTATION #{@name}"
+      notation = +"<!NOTATION #{@name}"
       reference_writer = ReferenceWriter.new(@middle, @public, @system, context)
       reference_writer.write(notation)
       notation << ">"

diff --git a/lib/rexml/element.rb b/lib/rexml/element.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative "parent"
 require_relative "namespace"
 require_relative "attribute"
@@ -356,7 +356,7 @@ def initialize( arg = UNDEFINED, parent=nil, context=nil )
     #   e.inspect # => "<foo bar='0' baz='1'> ... </>"
     #
     def inspect
-      rv = "<#@expanded_name"
+      rv = +"<#@expanded_name"
 
       @attributes.each_attribute do |attr|
         rv << " "
@@ -1524,7 +1524,7 @@ def _namespace_internal(namespaces = _calculate_namespaces) # :nodoc:
     def _namespace_lookup_internal(prefix, namespaces = _calculate_namespaces) # :nodoc:
       prefix = (prefix == '') ? 'xmlns' : prefix.delete_prefix("xmlns:")
       ns = namespaces[prefix]
-      ns = '' if ns.nil? and prefix == 'xmlns'
+      ns = +'' if ns.nil? and prefix == 'xmlns'
       ns
     end
 

diff --git a/lib/rexml/entity.rb b/lib/rexml/entity.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'set'
 require_relative 'child'
 require_relative 'parseexception'
@@ -127,7 +127,7 @@ def write out, indent=-1
 
     # Returns this entity as a string.  See write().
     def to_s
-      rv = ''
+      rv = +''
       write rv
       rv
     end
@@ -138,14 +138,14 @@ def to_s
   # CAUTION: these entities does not have parent and document
   module EntityConst
     # +>+
-    GT = Entity.new( 'gt', '>' )
+    GT = Entity.new( 'gt', '>' ).freeze
     # +<+
-    LT = Entity.new( 'lt', '<' )
+    LT = Entity.new( 'lt', '<' ).freeze
     # +&+
-    AMP = Entity.new( 'amp', '&' )
+    AMP = Entity.new( 'amp', '&' ).freeze
     # +"+
-    QUOT = Entity.new( 'quot', '"' )
+    QUOT = Entity.new( 'quot', '"' ).freeze
     # +'+
-    APOS = Entity.new( 'apos', "'" )
+    APOS = Entity.new( 'apos', "'" ).freeze
   end
 end
diff --git a/lib/rexml/functions.rb b/lib/rexml/functions.rb
@@ -8,8 +8,6 @@ module REXML
   # Therefore, in XML, "local-name()" is identical (and actually becomes)
   # "local_name()"
   class FunctionsClass # :nodoc:
-    @@available_functions = {}
-
     def initialize
       @context = nil
       @namespace_context = {}
@@ -26,14 +24,7 @@ def initialize
       :send,
       :compare_language,
       :string_value,
-    ]
-    class << self
-      def method_added(name)
-        unless INTERNAL_METHODS.include?(name)
-          @@available_functions[name] = true
-        end
-      end
-    end
+    ].freeze
 
     def namespace_context=(x) ; @namespace_context=x ; end
     def variables=(x) ; @variables=x ; end
@@ -415,7 +406,9 @@ def round( number )
     end
 
     def send(name, *args)
-      if @@available_functions[name.to_sym]
+      name = name.to_sym
+      if self.class.method_defined?(name, false) and
+          !INTERNAL_METHODS.include?(name)
         super
       else
         # TODO: Maybe, this is not XPath spec behavior.

diff --git a/lib/rexml/instruction.rb b/lib/rexml/instruction.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 require_relative "child"
 require_relative "source"
@@ -34,8 +34,8 @@ def initialize(target, content=nil)
         @content = target.content
       else
         message =
-          "processing instruction target must be String or REXML::Instruction: "
-        message << "<#{target.inspect}>"
+          "processing instruction target must be String or REXML::Instruction: " \
+          "<#{target.inspect}>"
         raise ArgumentError, message
       end
       @content.strip! if @content

diff --git a/lib/rexml/parsers/baseparser.rb b/lib/rexml/parsers/baseparser.rb
@@ -134,11 +134,11 @@ class BaseParser
       EREFERENCE = /&(?!#{NAME};)/
 
       DEFAULT_ENTITIES = {
-        'gt' => [/&gt;/, '&gt;', '>', />/],
-        'lt' => [/&lt;/, '&lt;', '<', /</],
-        'quot' => [/&quot;/, '&quot;', '"', /"/],
-        "apos" => [/&apos;/, "&apos;", "'", /'/]
-      }
+        'gt' => [/&gt;/, '&gt;', '>', />/].freeze,
+        'lt' => [/&lt;/, '&lt;', '<', /</].freeze,
+        'quot' => [/&quot;/, '&quot;', '"', /"/].freeze,
+        "apos" => [/&apos;/, "&apos;", "'", /'/].freeze
+      }.freeze
 
       module Private
         PEREFERENCE_PATTERN = /#{PEREFERENCE}/um
@@ -157,6 +157,7 @@ module Private
         default_entities.each do |term|
           DEFAULT_ENTITIES_PATTERNS[term] = /&#{term};/
         end
+        DEFAULT_ENTITIES_PATTERNS.freeze
         XML_PREFIXED_NAMESPACE = "http://www.w3.org/XML/1998/namespace"
         EXTERNAL_ID_PUBLIC_PATTERN = /\s+#{PUBIDLITERAL}\s+#{SYSTEMLITERAL}/um
         EXTERNAL_ID_SYSTEM_PATTERN  = /\s+#{SYSTEMLITERAL}/um

diff --git a/lib/rexml/security.rb b/lib/rexml/security.rb
@@ -1,28 +1,28 @@
 # frozen_string_literal: false
 module REXML
   module Security
-    @@entity_expansion_limit = 10_000
+    @entity_expansion_limit = 10_000
 
     # Set the entity expansion limit. By default the limit is set to 10000.
     def self.entity_expansion_limit=( val )
-      @@entity_expansion_limit = val
+      @entity_expansion_limit = val
     end
 
     # Get the entity expansion limit. By default the limit is set to 10000.
     def self.entity_expansion_limit
-      @@entity_expansion_limit
+      @entity_expansion_limit
     end
 
-    @@entity_expansion_text_limit = 10_240
+    @entity_expansion_text_limit = 10_240
 
     # Set the entity expansion limit. By default the limit is set to 10240.
     def self.entity_expansion_text_limit=( val )
-      @@entity_expansion_text_limit = val
+      @entity_expansion_text_limit = val
     end
 
     # Get the entity expansion limit. By default the limit is set to 10240.
     def self.entity_expansion_text_limit
-      @@entity_expansion_text_limit
+      @entity_expansion_text_limit
     end
   end
 end
diff --git a/lib/rexml/source.rb b/lib/rexml/source.rb
@@ -1,5 +1,5 @@
 # coding: US-ASCII
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 require "stringio"
 require "strscan"
@@ -78,6 +78,7 @@ module Private
           PRE_DEFINED_TERM_PATTERNS[term] = term
         end
       end
+      PRE_DEFINED_TERM_PATTERNS.freeze
     end
     private_constant :Private
 
@@ -227,9 +228,9 @@ def initialize(arg, block_size=500, encoding=nil)
       @pending_buffer = nil
 
       if encoding
-        super("", encoding)
+        super(+"", encoding)
       else
-        super(@source.read(3) || "")
+        super(@source.read(3) || +"")
       end
 
       if !@to_utf and
@@ -380,7 +381,7 @@ def encoding_updated
         @source.set_encoding(@encoding, @encoding)
       end
       @line_break = encode(">")
-      @pending_buffer, @scanner.string = @scanner.rest, ""
+      @pending_buffer, @scanner.string = @scanner.rest, +""
       @pending_buffer.force_encoding(@encoding)
       super
     end

diff --git a/lib/rexml/text.rb b/lib/rexml/text.rb
@@ -11,11 +11,11 @@ module REXML
   class Text < Child
     include Comparable
     # The order in which the substitutions occur
-    SPECIALS = [ /&(?!#?[\w-]+;)/u, /</u, />/u, /"/u, /'/u, /\r/u ]
-    SUBSTITUTES = ['&amp;', '&lt;', '&gt;', '&quot;', '&apos;', '&#13;']
+    SPECIALS = [ /&(?!#?[\w-]+;)/u, /</u, />/u, /"/u, /'/u, /\r/u ].freeze
+    SUBSTITUTES = ['&amp;', '&lt;', '&gt;', '&quot;', '&apos;', '&#13;'].freeze
     # Characters which are substituted in written strings
-    SLAICEPS = [ '<', '>', '"', "'", '&' ]
-    SETUTITSBUS = [ /&lt;/u, /&gt;/u, /&quot;/u, /&apos;/u, /&amp;/u ]
+    SLAICEPS = [ '<', '>', '"', "'", '&' ].freeze
+    SETUTITSBUS = [ /&lt;/u, /&gt;/u, /&quot;/u, /&apos;/u, /&amp;/u ].freeze
 
     # If +raw+ is true, then REXML leaves the value alone
     attr_accessor :raw
@@ -27,7 +27,7 @@ class Text < Child
       (0x20..0xD7FF),
       (0xE000..0xFFFD),
       (0x10000..0x10FFFF)
-    ]
+    ].freeze
 
     VALID_XML_CHARS = Regexp.new('^['+
       VALID_CHAR.map { |item|
@@ -38,7 +38,7 @@ class Text < Child
           [item.first, '-'.ord, item.last].pack('UUU').force_encoding('utf-8')
         end
       }.join +
-    ']*$')
+    ']*$').freeze
 
     # Constructor
     # +arg+ if a String, the content is set to the String.  If a Text,

diff --git a/lib/rexml/xmldecl.rb b/lib/rexml/xmldecl.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 require_relative 'encoding'
 require_relative 'source'
@@ -117,7 +117,7 @@ def content(enc)
         quote = "'"
       end
 
-      rv = "version=#{quote}#{@version}#{quote}"
+      rv = +"version=#{quote}#{@version}#{quote}"
       if @writeencoding or enc !~ /\Autf-8\z/i
         rv << " encoding=#{quote}#{enc}#{quote}"
       end

diff --git a/lib/rexml/xmltokens.rb b/lib/rexml/xmltokens.rb
@@ -58,8 +58,8 @@ module XMLTokens
       "\\u0300-\\u036F",
       "\\u203F-\\u2040",
     ]
-    NAME_START_CHAR = "[#{name_start_chars.join('')}]"
-    NAME_CHAR = "[#{name_chars.join('')}]"
+    NAME_START_CHAR = "[#{name_start_chars.join('')}]".freeze
+    NAME_CHAR = "[#{name_chars.join('')}]".freeze
     NAMECHAR = NAME_CHAR # deprecated. Use NAME_CHAR instead.
 
     # From http://www.w3.org/TR/xml-names11/#NT-NCName
@@ -70,13 +70,13 @@ module XMLTokens
     #
     #   [5] NCNameChar ::= NameChar - ':'
     ncname_chars = name_chars - [":"]
-    NCNAME_STR = "[#{ncname_start_chars.join('')}][#{ncname_chars.join('')}]*"
-    NAME_STR = "(?:#{NCNAME_STR}:)?#{NCNAME_STR}"
+    NCNAME_STR = "[#{ncname_start_chars.join('')}][#{ncname_chars.join('')}]*".freeze
+    NAME_STR = "(?:#{NCNAME_STR}:)?#{NCNAME_STR}".freeze
 
-    NAME = "(#{NAME_START_CHAR}#{NAME_CHAR}*)"
-    NMTOKEN = "(?:#{NAME_CHAR})+"
-    NMTOKENS = "#{NMTOKEN}(\\s+#{NMTOKEN})*"
-    REFERENCE = "(?:&#{NAME};|&#\\d+;|&#x[0-9a-fA-F]+;)"
+    NAME = "(#{NAME_START_CHAR}#{NAME_CHAR}*)".freeze
+    NMTOKEN = "(?:#{NAME_CHAR})+".freeze
+    NMTOKENS = "#{NMTOKEN}(\\s+#{NMTOKEN})*".freeze
+    REFERENCE = "(?:&#{NAME};|&#\\d+;|&#x[0-9a-fA-F]+;)".freeze
 
     #REFERENCE = "(?:#{ENTITYREF}|#{CHARREF})"
     #ENTITYREF = "&#{NAME};"

diff --git a/test/functions/test_base.rb b/test/functions/test_base.rb
@@ -19,7 +19,8 @@ def test_available_functions
         name namespace-uri normalize-space not number position round starts-with
         string string-length substring substring-after substring-before sum translate true
       ]
-      methods = REXML::FunctionsClass.class_variable_get(:@@available_functions).keys.sort
+      methods = REXML::FunctionsClass.instance_methods(false) -
+        REXML::FunctionsClass::INTERNAL_METHODS
       assert_equal expected_functions, methods.map { |m| m.to_s.tr('_', '-') }.sort
     end