Performance and memory optimizations (#94)

Originally, the inefficiency was discovered when working through the bug report in the `rubocop` repository - rubocop/rubocop#11657. Tested on the `rubocop` repository. `git clone` it, point `rexml` to the local repository, `bundle install` etc and run inside it: ``` bundle exec rubocop --profile --memory --format junit --out results/rubocop.xml lib/rubocop/cop/layout ``` ### Memory #### Before ``` Total allocated: 630.15 MB (8838482 objects) Total retained: 53.50 MB (445069 objects) allocated memory by gem ----------------------------------- 294.26 MB rexml/lib 214.78 MB rubocop/lib 38.60 MB rubocop-ast/lib 31.62 MB parser-3.2.1.0 31.43 MB other 10.02 MB lib 3.11 MB rubocop-rspec-2.18.1 1.95 MB rubocop-performance-1.16.0 1.83 MB regexp_parser-2.7.0 1.61 MB ast-2.4.2 405.71 kB unicode-display_width-2.4.2 287.16 kB rubocop-capybara-2.17.1 244.96 kB rubocop-rake-0.6.0 5.00 kB rubygems allocated memory by file ----------------------------------- 123.30 MB rexml/lib/rexml/text.rb 101.92 MB rubocop/lib/rubocop/formatter/junit_formatter.rb 61.42 MB rexml/lib/rexml/namespace.rb 31.07 MB rexml/lib/rexml/attribute.rb 28.89 MB rubocop/lib/rubocop/config.rb 27.30 MB rexml/lib/rexml/element.rb 22.75 MB rexml/lib/rexml/formatters/pretty.rb 22.75 MB rexml/lib/rexml/entity.rb 22.75 MB <internal:kernel> 15.11 MB parser-3.2.1.0/lib/parser/source/buffer.rb 12.59 MB rubocop-ast/lib/rubocop/ast/node.rb 12.03 MB rubocop/lib/rubocop/cop/registry.rb 11.88 MB rubocop/lib/rubocop/cop/team.rb 5.90 MB rubocop/lib/rubocop/cop/commissioner.rb 5.87 MB parser-3.2.1.0/lib/parser/lexer-F1.rb 5.69 MB rexml/lib/rexml/parent.rb 5.44 MB rubocop/lib/rubocop/cop/base.rb 5.17 MB rubocop-ast/lib/rubocop/ast/builder.rb 4.56 MB (eval) 4.25 MB parser-3.2.1.0/lib/parser/builders/default.rb 3.75 MB <internal:pack> 3.59 MB ruby/3.2.0/lib/ruby/3.2.0/psych/tree_builder.rb 3.53 MB rubocop/lib/rubocop/path_util.rb 3.21 MB rubocop/lib/rubocop/cli.rb 2.45 MB parser-3.2.1.0/lib/parser/ruby26.rb 2.27 MB rubocop-ast/lib/rubocop/ast/node_pattern/compiler/sequence_subcompiler.rb 2.23 MB rubocop-ast/lib/rubocop/ast/processed_source.rb 2.05 MB rubocop-ast/lib/rubocop/ast/node/if_node.rb 2.00 MB rubocop-ast/lib/rubocop/ast/token.rb 1.73 MB rubocop-ast/lib/rubocop/ast/node_pattern/method_definer.rb 1.73 MB ruby/3.2.0/lib/ruby/3.2.0/erb/compiler.rb 1.61 MB ast-2.4.2/lib/ast/node.rb 1.54 MB rubocop/lib/rubocop/cop/variable_force.rb 1.53 MB rubocop/lib/rubocop/cop/internal_affairs/cop_description.rb 1.49 MB rubocop/lib/rubocop/cop/naming/inclusive_language.rb 1.47 MB rubocop-ast/lib/rubocop/ast/node/mixin/parameterized_node.rb 1.42 MB rubocop-ast/lib/rubocop/ast/node_pattern/compiler.rb 1.42 MB rubocop-ast/lib/rubocop/ast/node_pattern/compiler/node_pattern_subcompiler.rb 1.39 MB rubocop/lib/rubocop/cop/layout/redundant_line_break.rb 1.35 MB rubocop/lib/rubocop/cop/util.rb 1.29 MB regexp_parser-2.7.0/lib/regexp_parser/scanner.rb 1.29 MB rubocop/lib/rubocop/cop/mixin/range_help.rb 1.27 MB ruby/3.2.0/lib/ruby/3.2.0/psych/parser.rb 1.18 MB rubocop/lib/rubocop/cop/layout/comment_indentation.rb 1.17 MB rubocop-ast/lib/rubocop/ast/node/mixin/descendence.rb 1.10 MB ruby/3.2.0/lib/ruby/3.2.0/erb.rb 1.07 MB rubocop/lib/rubocop/cop/variable_force/variable_table.rb 1.04 MB rubocop/lib/rubocop/cop/layout/end_of_line.rb 1.01 MB rubocop/lib/rubocop/cop/mixin/end_keyword_alignment.rb 996.49 kB rubocop/lib/rubocop/cop/metrics/utils/abc_size_calculator.rb allocated memory by location ----------------------------------- 87.70 MB rubocop/lib/rubocop/formatter/junit_formatter.rb:65 61.19 MB rexml/lib/rexml/text.rb:385 36.04 MB rexml/lib/rexml/text.rb:134 35.83 MB rexml/lib/rexml/namespace.rb:19 26.06 MB rexml/lib/rexml/text.rb:374 22.75 MB rexml/lib/rexml/entity.rb:136 22.75 MB <internal:kernel>:49 17.16 MB rubocop/lib/rubocop/config.rb:37 15.77 MB rexml/lib/rexml/attribute.rb:127 15.30 MB rexml/lib/rexml/attribute.rb:125 13.08 MB rexml/lib/rexml/element.rb:331 11.37 MB rexml/lib/rexml/element.rb:2382 11.37 MB rubocop/lib/rubocop/formatter/junit_formatter.rb:56 9.89 MB parser-3.2.1.0/lib/parser/source/buffer.rb:205 9.86 MB rubocop/lib/rubocop/cop/team.rb:32 8.53 MB rexml/lib/rexml/namespace.rb:23 8.53 MB rexml/lib/rexml/namespace.rb:24 8.53 MB rexml/lib/rexml/namespace.rb:26 5.86 MB rubocop/lib/rubocop/cop/registry.rb:54 5.69 MB rexml/lib/rexml/formatters/pretty.rb:40 5.69 MB rexml/lib/rexml/formatters/pretty.rb:44 5.39 MB rubocop/lib/rubocop/config.rb:319 4.55 MB (eval):3 4.20 MB rubocop/lib/rubocop/config.rb:34 3.84 MB rubocop-ast/lib/rubocop/ast/node.rb:93 3.73 MB <internal:pack>:21 3.71 MB rubocop/lib/rubocop/cop/base.rb:346 3.58 MB ruby/3.2.0/lib/ruby/3.2.0/psych/tree_builder.rb:97 3.52 MB rubocop/lib/rubocop/path_util.rb:55 3.50 MB rubocop-ast/lib/rubocop/ast/builder.rb:99 3.21 MB rubocop/lib/rubocop/cli.rb:92 3.00 MB parser-3.2.1.0/lib/parser/lexer-F1.rb:14606 2.91 MB rubocop/lib/rubocop/cop/registry.rb:52 2.84 MB rexml/lib/rexml/parent.rb:116 2.84 MB rexml/lib/rexml/element.rb:330 2.84 MB rexml/lib/rexml/parent.rb:15 2.84 MB rexml/lib/rexml/formatters/pretty.rb:41 2.84 MB rexml/lib/rexml/formatters/pretty.rb:85 2.84 MB rexml/lib/rexml/formatters/pretty.rb:78 2.84 MB rexml/lib/rexml/formatters/pretty.rb:52 2.84 MB rubocop/lib/rubocop/formatter/junit_formatter.rb:52 2.84 MB rubocop-ast/lib/rubocop/ast/node.rb:236 1.89 MB parser-3.2.1.0/lib/parser/lexer-F1.rb:14602 1.86 MB parser-3.2.1.0/lib/parser/source/buffer.rb:117 1.74 MB rubocop-ast/lib/rubocop/ast/processed_source.rb:185 1.69 MB rubocop-ast/lib/rubocop/ast/token.rb:14 1.67 MB rubocop-ast/lib/rubocop/ast/builder.rb:98 1.66 MB rubocop/lib/rubocop/cop/commissioner.rb:125 1.52 MB rubocop/lib/rubocop/cop/base.rb:286 1.49 MB rubocop/lib/rubocop/cop/internal_affairs/cop_description.rb:80 ``` #### After ``` Total allocated: 367.43 MB (4224322 objects) 🔥 🔥 🔥 Total retained: 53.50 MB (445067 objects) allocated memory by gem ----------------------------------- 214.62 MB rubocop/lib 54.44 MB rexml/lib 38.60 MB rubocop-ast/lib 31.62 MB parser-3.2.1.0 10.02 MB lib 8.69 MB other 3.11 MB rubocop-rspec-2.18.1 1.95 MB rubocop-performance-1.16.0 1.83 MB regexp_parser-2.7.0 1.61 MB ast-2.4.2 405.71 kB unicode-display_width-2.4.2 287.16 kB rubocop-capybara-2.17.1 244.96 kB rubocop-rake-0.6.0 5.00 kB rubygems allocated memory by file ----------------------------------- 101.92 MB rubocop/lib/rubocop/formatter/junit_formatter.rb 28.89 MB rubocop/lib/rubocop/config.rb 27.30 MB rexml/lib/rexml/element.rb 15.77 MB rexml/lib/rexml/attribute.rb 15.11 MB parser-3.2.1.0/lib/parser/source/buffer.rb 12.59 MB rubocop-ast/lib/rubocop/ast/node.rb 12.03 MB rubocop/lib/rubocop/cop/registry.rb 11.88 MB rubocop/lib/rubocop/cop/team.rb 5.90 MB rubocop/lib/rubocop/cop/commissioner.rb 5.87 MB parser-3.2.1.0/lib/parser/lexer-F1.rb 5.69 MB rexml/lib/rexml/parent.rb 5.69 MB rexml/lib/rexml/formatters/pretty.rb 5.44 MB rubocop/lib/rubocop/cop/base.rb 5.17 MB rubocop-ast/lib/rubocop/ast/builder.rb 4.56 MB (eval) 4.25 MB parser-3.2.1.0/lib/parser/builders/default.rb 3.75 MB <internal:pack> 3.59 MB ruby/3.2.0/lib/ruby/3.2.0/psych/tree_builder.rb 3.53 MB rubocop/lib/rubocop/path_util.rb 3.05 MB rubocop/lib/rubocop/cli.rb 2.45 MB parser-3.2.1.0/lib/parser/ruby26.rb 2.27 MB rubocop-ast/lib/rubocop/ast/node_pattern/compiler/sequence_subcompiler.rb 2.23 MB rubocop-ast/lib/rubocop/ast/processed_source.rb 2.05 MB rubocop-ast/lib/rubocop/ast/node/if_node.rb 2.00 MB rubocop-ast/lib/rubocop/ast/token.rb 1.73 MB rubocop-ast/lib/rubocop/ast/node_pattern/method_definer.rb 1.73 MB ruby/3.2.0/lib/ruby/3.2.0/erb/compiler.rb 1.61 MB ast-2.4.2/lib/ast/node.rb 1.54 MB rubocop/lib/rubocop/cop/variable_force.rb 1.53 MB rubocop/lib/rubocop/cop/internal_affairs/cop_description.rb 1.49 MB rubocop/lib/rubocop/cop/naming/inclusive_language.rb 1.47 MB rubocop-ast/lib/rubocop/ast/node/mixin/parameterized_node.rb 1.42 MB rubocop-ast/lib/rubocop/ast/node_pattern/compiler.rb 1.42 MB rubocop-ast/lib/rubocop/ast/node_pattern/compiler/node_pattern_subcompiler.rb 1.39 MB rubocop/lib/rubocop/cop/layout/redundant_line_break.rb 1.35 MB rubocop/lib/rubocop/cop/util.rb 1.29 MB regexp_parser-2.7.0/lib/regexp_parser/scanner.rb 1.29 MB rubocop/lib/rubocop/cop/mixin/range_help.rb 1.27 MB ruby/3.2.0/lib/ruby/3.2.0/psych/parser.rb 1.18 MB rubocop/lib/rubocop/cop/layout/comment_indentation.rb 1.17 MB rubocop-ast/lib/rubocop/ast/node/mixin/descendence.rb 1.10 MB ruby/3.2.0/lib/ruby/3.2.0/erb.rb 1.07 MB rubocop/lib/rubocop/cop/variable_force/variable_table.rb 1.04 MB rubocop/lib/rubocop/cop/layout/end_of_line.rb 1.01 MB rubocop/lib/rubocop/cop/mixin/end_keyword_alignment.rb 996.49 kB rubocop/lib/rubocop/cop/metrics/utils/abc_size_calculator.rb 970.58 kB rubocop/lib/rubocop/cop/style/redundant_self.rb 947.97 kB rubocop/lib/rubocop/cop/layout/empty_comment.rb 938.93 kB rubocop/lib/rubocop/cop/mixin/empty_lines_around_body.rb 871.31 kB rubocop/lib/rubocop/cop/variable_force/variable.rb allocated memory by location ----------------------------------- 87.70 MB rubocop/lib/rubocop/formatter/junit_formatter.rb:65 17.16 MB rubocop/lib/rubocop/config.rb:37 15.77 MB rexml/lib/rexml/attribute.rb:127 13.08 MB rexml/lib/rexml/element.rb:331 11.37 MB rexml/lib/rexml/element.rb:2382 11.37 MB rubocop/lib/rubocop/formatter/junit_formatter.rb:56 9.89 MB parser-3.2.1.0/lib/parser/source/buffer.rb:205 9.86 MB rubocop/lib/rubocop/cop/team.rb:32 5.86 MB rubocop/lib/rubocop/cop/registry.rb:54 5.39 MB rubocop/lib/rubocop/config.rb:319 4.55 MB (eval):3 4.20 MB rubocop/lib/rubocop/config.rb:34 3.84 MB rubocop-ast/lib/rubocop/ast/node.rb:93 3.73 MB <internal:pack>:21 3.71 MB rubocop/lib/rubocop/cop/base.rb:346 3.58 MB ruby/3.2.0/lib/ruby/3.2.0/psych/tree_builder.rb:97 3.52 MB rubocop/lib/rubocop/path_util.rb:55 3.50 MB rubocop-ast/lib/rubocop/ast/builder.rb:99 3.05 MB rubocop/lib/rubocop/cli.rb:92 3.00 MB parser-3.2.1.0/lib/parser/lexer-F1.rb:14606 2.91 MB rubocop/lib/rubocop/cop/registry.rb:52 2.84 MB rexml/lib/rexml/parent.rb:116 2.84 MB rexml/lib/rexml/element.rb:330 2.84 MB rexml/lib/rexml/parent.rb:15 2.84 MB rexml/lib/rexml/formatters/pretty.rb:40 2.84 MB rexml/lib/rexml/formatters/pretty.rb:41 2.84 MB rubocop/lib/rubocop/formatter/junit_formatter.rb:52 2.84 MB rubocop-ast/lib/rubocop/ast/node.rb:236 1.89 MB parser-3.2.1.0/lib/parser/lexer-F1.rb:14602 1.86 MB parser-3.2.1.0/lib/parser/source/buffer.rb:117 1.74 MB rubocop-ast/lib/rubocop/ast/processed_source.rb:185 1.69 MB rubocop-ast/lib/rubocop/ast/token.rb:14 1.67 MB rubocop-ast/lib/rubocop/ast/builder.rb:98 1.66 MB rubocop/lib/rubocop/cop/commissioner.rb:125 1.52 MB rubocop/lib/rubocop/cop/base.rb:286 1.49 MB rubocop/lib/rubocop/cop/internal_affairs/cop_description.rb:80 1.47 MB parser-3.2.1.0/lib/parser/source/buffer.rb:274 1.41 MB ast-2.4.2/lib/ast/node.rb:77 1.35 MB parser-3.2.1.0/lib/parser/ruby26.rb:0 1.30 MB rubocop/lib/rubocop/cop/commissioner.rb:153 1.27 MB ruby/3.2.0/lib/ruby/3.2.0/psych/parser.rb:62 1.25 MB rubocop-ast/lib/rubocop/ast/node.rb:106 1.24 MB rubocop/lib/rubocop/cop/registry.rb:181 1.16 MB parser-3.2.1.0/lib/parser/source/buffer.rb:254 1.10 MB ruby/3.2.0/lib/ruby/3.2.0/erb.rb:429 1.07 MB rubocop-ast/lib/rubocop/ast/node_pattern/method_definer.rb:58 1.04 MB rubocop/lib/rubocop/cop/layout/end_of_line.rb:50 988.72 kB rubocop/lib/rubocop/config.rb:322 982.96 kB rubocop-ast/lib/rubocop/ast/node/mixin/parameterized_node.rb:91 975.88 kB rubocop-ast/lib/rubocop/ast/node/if_node.rb:141 ``` So, `-42%` of allocated memory and `-52%` of allocated objects. ### CPU #### Before ``` TOTAL (pct) SAMPLES (pct) FRAME 2620 (10.0%) 2620 (10.0%) Dir.pwd ==> 2314 (8.9%) 2314 (8.9%) String#gsub ==> 1538 (5.9%) 1531 (5.9%) String#scan ==> 4376 (16.8%) 960 (3.7%) REXML::Text.normalize 5223 (20.0%) 907 (3.5%) Class#new ==> 895 (3.4%) 895 (3.4%) Regexp#=== 879 (3.4%) 740 (2.8%) Enumerable#find 660 (2.5%) 660 (2.5%) IO#write ==> 732 (2.8%) 641 (2.5%) Kernel#clone ==> 618 (2.4%) 618 (2.4%) String#=~ ==> 2244 (8.6%) 579 (2.2%) REXML::Formatters::Pretty#write_element ==> 1086 (4.2%) 484 (1.9%) REXML::Namespace#name= 795 (3.0%) 381 (1.5%) Parser::Lexer#advance 362 (1.4%) 362 (1.4%) String#[] 677 (2.6%) 308 (1.2%) REXML::Attribute#to_string 574 (2.2%) 286 (1.1%) REXML::Namespace#name= 286 (1.1%) 268 (1.0%) REXML::Element#root 1844 (7.1%) 256 (1.0%) Racc::Parser#_racc_do_parse_c 556 (2.1%) 236 (0.9%) Kernel#require_relative 8190 (31.3%) 233 (0.9%) REXML::Attributes#[]= 3913 (15.0%) 230 (0.9%) RuboCop::Cop::Commissioner#trigger_responding_cops 26099 (99.9%) 224 (0.9%) Array#each 820 (3.1%) 223 (0.9%) RuboCop::Config#initialize 273 (1.0%) 222 (0.8%) Kernel#dup 6009 (23.0%) 200 (0.8%) Kernel#public_send 4961 (19.0%) 189 (0.7%) Hash#each_value 3749 (14.4%) 173 (0.7%) RuboCop::Formatter::JUnitFormatter#classname_attribute_value 13301 (50.9%) 165 (0.6%) RuboCop::Formatter::JUnitFormatter#add_testcase_element_to_testsuite_element 325 (1.2%) 139 (0.5%) RuboCop::Cop::Registry#clear_enrollment_queue 1554 (5.9%) 134 (0.5%) Array#select ``` #### After ``` TOTAL (pct) SAMPLES (pct) FRAME 1878 (12.1%) 1878 (12.1%) Dir.pwd 783 (5.1%) 783 (5.1%) String#gsub 3091 (20.0%) 739 (4.8%) Class#new 692 (4.5%) 607 (3.9%) Enumerable#find 702 (4.5%) 339 (2.2%) Parser::Lexer#advance 317 (2.0%) 317 (2.0%) IO#write 283 (1.8%) 283 (1.8%) String#[] 275 (1.8%) 275 (1.8%) String#match? 267 (1.7%) 262 (1.7%) String#scan 244 (1.6%) 230 (1.5%) REXML::Element#root 1551 (10.0%) 205 (1.3%) Racc::Parser#_racc_do_parse_c 236 (1.5%) 201 (1.3%) Kernel#dup 196 (1.3%) 179 (1.2%) REXML::Attribute#to_string 4037 (26.1%) 177 (1.1%) Kernel#public_send 3286 (21.2%) 176 (1.1%) RuboCop::Cop::Commissioner#trigger_responding_cops 15481 (100.0%) 176 (1.1%) Array#each 460 (3.0%) 166 (1.1%) Kernel#require_relative 661 (4.3%) 141 (0.9%) RuboCop::Config#initialize 2099 (13.6%) 141 (0.9%) REXML::Attributes#[]= 2866 (18.5%) 139 (0.9%) RuboCop::Formatter::JUnitFormatter#classname_attribute_value 292 (1.9%) 132 (0.9%) RuboCop::Cop::Registry#clear_enrollment_queue 126 (0.8%) 126 (0.8%) File.fnmatch? 874 (5.6%) 123 (0.8%) REXML::Formatters::Pretty#write_element 113 (0.7%) 113 (0.7%) Symbol#to_s 1348 (8.7%) 107 (0.7%) Array#select 103 (0.7%) 101 (0.7%) RuboCop::Cop::Registry#initialize 5611 (36.2%) 91 (0.6%) RuboCop::Formatter::JUnitFormatter#add_testcase_element_to_testsuite_element 269 (1.7%) 91 (0.6%) REXML::Text.normalize 89 (0.6%) 89 (0.6%) String#tr 161 (1.0%) 85 (0.5%) Parser::Lexer#emit ``` ### Time #### Before ``` $ time bundle exec rubocop --cache false --format junit --out results/rubocop.xml lib/rubocop/cop/layout bundle exec rubocop --cache false --format junit --out results/rubocop.xml 12.28s user 2.02s system 99% cpu 14.313 total ``` #### After ``` $ time bundle exec rubocop --cache false --format junit --out results/rubocop.xml lib/rubocop/cop/layout bundle exec rubocop --cache false --format junit --out results/rubocop.xml 10.17s user 1.97s system 99% cpu 12.150 total ``` **Note**: There is also a difference in time needed to run this gem's tests after this PR changes. Feel free to ask clarifying questions if some changes are not clear. Co-authored-by: Sutou Kouhei <[email protected]>
ruby · Mar 21, 2023 · f44e88d · f44e88d
1 parent cbb9c1f
commit f44e88d
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Showing 7 changed files with 52 additions and 35 deletions.
diff --git a/lib/rexml/attribute.rb b/lib/rexml/attribute.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative "namespace"
 require_relative 'text'
 
@@ -119,10 +119,13 @@ def hash
     #  b = Attribute.new( "ns:x", "y" )
     #  b.to_string     # -> "ns:x='y'"
     def to_string
+      value = to_s
       if @element and @element.context and @element.context[:attribute_quote] == :quote
-        %Q^#@expanded_name="#{to_s().gsub(/"/, '&quot;')}"^
+        value = value.gsub('"', '&quot;') if value.include?('"')
+        %Q^#@expanded_name="#{value}"^
       else
-        "#@expanded_name='#{to_s().gsub(/'/, '&apos;')}'"
+        value = value.gsub("'", '&apos;') if value.include?("'")
+        "#@expanded_name='#{value}'"
       end
     end
 
@@ -192,7 +195,7 @@ def node_type
     end
 
     def inspect
-      rv = ""
+      rv = +""
       write( rv )
       rv
     end

diff --git a/lib/rexml/entity.rb b/lib/rexml/entity.rb
@@ -132,24 +132,34 @@ def to_s
     # then:
     #  doctype.entity('yada').value   #-> "nanoo bar nanoo"
     def value
-      if @value
-        matches = @value.scan(PEREFERENCE_RE)
-        rv = @value.clone
-        if @parent
-          sum = 0
-          matches.each do |entity_reference|
-            entity_value = @parent.entity( entity_reference[0] )
-            if sum + entity_value.bytesize > Security.entity_expansion_text_limit
-              raise "entity expansion has grown too large"
-            else
-              sum += entity_value.bytesize
-            end
-            rv.gsub!( /%#{entity_reference.join};/um, entity_value )
+      @resolved_value ||= resolve_value
+    end
+
+    def parent=(other)
+      @resolved_value = nil
+      super
+    end
+
+    private
+    def resolve_value
+      return nil if @value.nil?
+      return @value unless @value.match?(PEREFERENCE_RE)
+
+      matches = @value.scan(PEREFERENCE_RE)
+      rv = @value.clone
+      if @parent
+        sum = 0
+        matches.each do |entity_reference|
+          entity_value = @parent.entity( entity_reference[0] )
+          if sum + entity_value.bytesize > Security.entity_expansion_text_limit
+            raise "entity expansion has grown too large"
+          else
+            sum += entity_value.bytesize
           end
+          rv.gsub!( /%#{entity_reference.join};/um, entity_value )
         end
-        return rv
       end
-      nil
+      rv
     end
   end
 

diff --git a/lib/rexml/formatters/pretty.rb b/lib/rexml/formatters/pretty.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'default'
 
 module REXML
@@ -58,7 +58,7 @@ def write_element(node, output)
           skip = false
           if compact
             if node.children.inject(true) {|s,c| s & c.kind_of?(Text)}
-              string = ""
+              string = +""
               old_level = @level
               @level = 0
               node.children.each { |child| write( child, string ) }

diff --git a/lib/rexml/namespace.rb b/lib/rexml/namespace.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 require_relative 'xmltokens'
 
@@ -10,21 +10,25 @@ module Namespace
     # The expanded name of the object, valid if name is set
     attr_accessor :prefix
     include XMLTokens
+    NAME_WITHOUT_NAMESPACE = /\A#{NCNAME_STR}\z/
     NAMESPLIT = /^(?:(#{NCNAME_STR}):)?(#{NCNAME_STR})/u
 
     # Sets the name and the expanded name
     def name=( name )
       @expanded_name = name
-      case name
-      when NAMESPLIT
+      if name.match?(NAME_WITHOUT_NAMESPACE)
+        @prefix = ""
+        @namespace = ""
+        @name = name
+      elsif name =~ NAMESPLIT
         if $1
           @prefix = $1
         else
           @prefix = ""
           @namespace = ""
         end
         @name = $2
-      when ""
+      elsif name == ""
         @prefix = nil
         @namespace = nil
         @name = nil

diff --git a/lib/rexml/text.rb b/lib/rexml/text.rb
@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require_relative 'security'
 require_relative 'entity'
 require_relative 'doctype'
@@ -131,7 +131,7 @@ def parent= parent
     def Text.check string, pattern, doctype
 
       # illegal anywhere
-      if string !~ VALID_XML_CHARS
+      if !string.match?(VALID_XML_CHARS)
         if String.method_defined? :encode
           string.chars.each do |c|
             case c.ord
@@ -371,7 +371,7 @@ def Text::normalize( input, doctype=nil, entity_filter=nil )
       copy = input.to_s
       # Doing it like this rather than in a loop improves the speed
       #copy = copy.gsub( EREFERENCE, '&amp;' )
-      copy = copy.gsub( "&", "&amp;" )
+      copy = copy.gsub( "&", "&amp;" ) if copy.include?("&")
       if doctype
         # Replace all ampersands that aren't part of an entity
         doctype.entities.each_value do |entity|
@@ -382,7 +382,9 @@ def Text::normalize( input, doctype=nil, entity_filter=nil )
       else
         # Replace all ampersands that aren't part of an entity
         DocType::DEFAULT_ENTITIES.each_value do |entity|
-          copy = copy.gsub(entity.value, "&#{entity.name};" )
+          if copy.include?(entity.value)
+            copy = copy.gsub(entity.value, "&#{entity.name};" )
+          end
         end
       end
       copy

diff --git a/test/test_core.rb b/test/test_core.rb
@@ -1423,7 +1423,7 @@ def test_ticket_91
       d.root.add_element( "bah" )
       p=REXML::Formatters::Pretty.new(2)
       p.compact = true    # Don't add whitespace to text nodes unless necessary
-      p.write(d,out="")
+      p.write(d,out=+"")
       assert_equal( expected, out )
     end
 

diff --git a/test/test_document.rb b/test/test_document.rb
@@ -166,11 +166,9 @@ def test_empty_value
 <cd></cd>
 EOF
 
-          assert_raise(REXML::ParseException) do
-            REXML::Document.new(xml)
-          end
-          REXML::Security.entity_expansion_limit = 100
-          assert_equal(100, REXML::Security.entity_expansion_limit)
+          REXML::Document.new(xml)
+          REXML::Security.entity_expansion_limit = 90
+          assert_equal(90, REXML::Security.entity_expansion_limit)
           assert_raise(REXML::ParseException) do
             REXML::Document.new(xml)
           end