(PUP-11515) Negative Lookbehind Regex Causes Duplicate Node

Before this commit, two nodes could collide due to the lookaround
Regex pattern. This issue arose because the regex was converted to
a regular string by ignoring characters other than a-z, 0-9, _, and -.

For example, /(?<!a)sync/ was converted to "__node_regexp__async,"
and /async/ was also converted to "__node_regexp__async," causing
an error that the node was already defined.

To prevent such duplication, this commit normalize the lookarround
pattern from the regex, ensuring a unique string in case
of lookarround pattern conflict.

For example, /(?<!a)sync/ will converted to "__node_regexp__LPQULTEXaRPsync"
replacing (?<!a) to "LPQULTEXaRP" while converting to the string.

Author: imaqsood

lib/puppet/resource/type.rb

@@ -33,6 +33,16 @@ class Puppet::Resource::Type
   DOUBLE_COLON = '::'
   EMPTY_ARRAY = [].freeze
 
+  LOOKAROUND_OPERATORS = {
+    "(" => 'LP',
+    "?" => "QU",
+    "<" => "LT",
+    ">" => "GT",
+    "!" => "EX",
+    "=" => "EQ",
+    ")" => 'RP'
+  }.freeze
+
   attr_accessor :file, :line, :doc, :code, :parent, :resource_type_collection, :override
   attr_reader :namespace, :arguments, :behaves_like, :module_name
 
@@ -196,7 +206,11 @@ def instantiate_resource(scope, resource)
 
   def name
     if type == :node && name_is_regex?
-      "__node_regexp__#{@name.source.downcase.gsub(/[^-\w:.]/, '').sub(/^\.+/, '')}"
+      # Normalize lookarround regex patthern
+      internal_name = @name.source.downcase.gsub(/\(\?[^)]*\)/) do |str|
+        str.gsub(/./) { |ch| LOOKAROUND_OPERATORS[ch] || ch }
+      end
+      "__node_regexp__#{internal_name.gsub(/[^-\w:.]/, '').sub(/^\.+/, '')}"
     else
       @name
     end

spec/integration/parser/node_spec.rb

@@ -85,6 +85,15 @@ class foo {
       end.not_to raise_error
     end
 
+    it 'does not raise an error with 2 regex node names are the same due to lookarround pattern' do
+      expect do
+        compile_to_catalog(<<-MANIFEST, Puppet::Node.new("async"))
+        node /(?<!a)sync/ { }
+        node /async/ { }
+        MANIFEST
+      end.not_to raise_error
+    end
+
     it 'errors when two nodes with regexes collide after some regex syntax is removed' do
       expect do
         compile_to_catalog(<<-MANIFEST)