Add patch for WikiCloth

See https://gitlab.com/gitlab-org/gitlab/-/issues/334056#note_745336618

Changelog: fixed
MR: ...

config/initializers/wikicloth_patch.rb

+# frozen_string_literal: true
+
+require 'wikicloth'
+require 'wikicloth/wiki_buffer/var'
+
+# Adds patch for changes in this PR: https://github.com/nricciar/wikicloth/pull/112/files
+#
+# That fix has already been merged, but the maintainers are not releasing new versions, so we
+# need to patch it here.
+#
+# If they ever do release a version, then we can remove this file.
+#
+# See: https://gitlab.com/gitlab-org/gitlab/-/issues/334056#note_745336618
+
+# Guard to ensure we remember to delete this patch if they ever release a new version of wikicloth
+raise 'New version of WikiCloth detected, please remove this patch' unless Gem::Version.new(WikiCloth::VERSION) == Gem::Version.new('0.8.1')
+
+# rubocop:disable Style/ClassAndModuleChildren
+# rubocop:disable Layout/SpaceAroundEqualsInParameterDefault
+# rubocop:disable Style/HashSyntax
+# rubocop:disable Layout/SpaceAfterComma
+# rubocop:disable Style/RescueStandardError
+# rubocop:disable Rails/Output
+# rubocop:disable Style/MethodCallWithoutArgsParentheses
+# rubocop:disable Layout/EmptyLinesAroundClassBody
+# rubocop:disable Metrics/AbcSize
+# rubocop:disable Metrics/CyclomaticComplexity
+# rubocop:disable Metrics/PerceivedComplexity
+# rubocop:disable Cop/LineBreakAroundConditionalBlock
+# rubocop:disable Layout/EmptyLineAfterGuardClause
+# rubocop:disable Performance/ReverseEach
+# rubocop:disable Style/BlockDelimiters
+# rubocop:disable Cop/LineBreakAroundConditionalBlock
+# rubocop:disable Layout/MultilineBlockLayout
+# rubocop:disable Layout/BlockEndNewline
+module WikiCloth
+  class WikiCloth
+    def render(opt={})
+      self.options = { :noedit => false, :locale => I18n.default_locale, :fast => true, :output => :html, :link_handler => self.link_handler,
+                       :params => self.params, :sections => self.sections }.merge(self.options).merge(opt)
+      self.options[:link_handler].params = options[:params]
+
+      I18n.locale = self.options[:locale]
+
+      data = self.sections.collect { |s| s.render(self.options) }.join
+
+      # This is the first patched line from:
+      # https://github.com/nricciar/wikicloth/pull/112/files#diff-eed3de11b953105f9181a6859d58f52af8912d28525fd2a289f8be184e66f531R69
+      data.gsub!(/<!--.*?-->/m,"")
+
+      data << "\n" if data.last(1) != "\n"
+      data << "garbage"
+
+      buffer = WikiBuffer.new("",options)
+
+      begin
+        if self.options[:fast]
+          until data.empty?
+            case data
+            when /\A\w+/
+              data = $'
+              @current_row += $&.length
+              buffer.add_word($&)
+            when /\A[^\w]+(\w|)/m
+              data = $'
+              $&.each_char { |c| add_current_char(buffer,c) }
+            end
+          end
+        else
+          data.each_char { |c| add_current_char(buffer,c) }
+        end
+      rescue => err
+        debug_tree = buffer.buffers.collect { |b| b.debug }.join("-->")
+        puts I18n.t("unknown error on line", :line => @current_line, :row => @current_row, :tree => debug_tree)
+        raise err
+      end
+
+      buffer.eof()
+      buffer.send("to_#{self.options[:output]}")
+    end
+
+  end
+
+  class WikiBuffer::Var < WikiBuffer
+    def to_html
+      return "" if will_not_be_rendered
+
+      if self.is_function?
+        if Extension.function_exists?(function_name)
+          return Extension.functions[function_name][:klass].new(@options).instance_exec( params.collect { |p| p.strip }, &Extension.functions[function_name][:block] ).to_s
+        end
+        ret = default_functions(function_name,params.collect { |p| p.strip })
+        ret ||= @options[:link_handler].function(function_name, params.collect { |p| p.strip })
+        ret.to_s
+      elsif self.is_param?
+        ret = nil
+        @options[:buffer].buffers.reverse.each do |b|
+          ret = b.get_param(params[0],params[1]) if b.instance_of?(WikiBuffer::HTMLElement) && b.element_name == "template"
+          break unless ret.nil?
+        end
+        ret.to_s
+      else
+        # put template at beginning of buffer
+        template_stack = @options[:buffer].buffers.collect { |b| b.get_param("__name") if b.instance_of?(WikiBuffer::HTMLElement) &&
+          b.element_name == "template" }.compact
+        if template_stack.last == params[0]
+          debug_tree = @options[:buffer].buffers.collect { |b| b.debug }.join("-->")
+          "<span class=\"error\">#{I18n.t('template loop detected', :tree => debug_tree)}</span>"
+        else
+          key = params[0].to_s.strip
+          key_options = params[1..-1].collect { |p| p.is_a?(Hash) ? { :name => p[:name].strip, :value => p[:value].strip } : p.strip }
+          key_options ||= []
+          key_digest = Digest::MD5.hexdigest(key_options.to_a.sort {|x,y| (x.is_a?(Hash) ? x[:name] : x) <=> (y.is_a?(Hash) ? y[:name] : y) }.inspect)
+
+          return @options[:params][key] if @options[:params].has_key?(key)
+          # if we have a valid cache fragment use it
+          return @options[:cache][key][key_digest] unless @options[:cache].nil? || @options[:cache][key].nil? || @options[:cache][key][key_digest].nil?
+
+          ret = @options[:link_handler].include_resource(key,key_options).to_s
+
+          # This is the second patched line from:
+          # https://github.com/nricciar/wikicloth/pull/112/files#diff-f262faf4fadb222cca87185be0fb65b3f49659abc840794cc83a736d41310fb1R83
+          ret.gsub!(/<!--.*?-->/m,"") unless ret.frozen?
+
+          count = 0
+          tag_attr = key_options.collect { |p|
+            if p.instance_of?(Hash)
+              "#{p[:name]}=\"#{p[:value].gsub(/"/,'&quot;')}\""
+            else
+              count += 1
+              "#{count}=\"#{p.gsub(/"/,'&quot;')}\""
+            end
+          }.join(" ")
+
+          self.data = ret.blank? ? "" : "<template __name=\"#{key}\" __hash=\"#{key_digest}\" #{tag_attr}>#{ret}</template>"
+          ""
+        end
+      end
+    end
+  end
+end
+# rubocop:enable Style/ClassAndModuleChildren
+# rubocop:enable Layout/SpaceAroundEqualsInParameterDefault
+# rubocop:enable Style/HashSyntax
+# rubocop:enable Layout/SpaceAfterComma
+# rubocop:enable Style/RescueStandardError
+# rubocop:enable Rails/Output
+# rubocop:enable Style/MethodCallWithoutArgsParentheses
+# rubocop:enable Layout/EmptyLinesAroundClassBody
+# rubocop:enable Metrics/AbcSize
+# rubocop:enable Metrics/CyclomaticComplexity
+# rubocop:enable Metrics/PerceivedComplexity
+# rubocop:enable Cop/LineBreakAroundConditionalBlock
+# rubocop:enable Layout/EmptyLineAfterGuardClause
+# rubocop:enable Performance/ReverseEach
+# rubocop:enable Style/BlockDelimiters
+# rubocop:enable Cop/LineBreakAroundConditionalBlock
+# rubocop:enable Layout/MultilineBlockLayout
+# rubocop:enable Layout/BlockEndNewline