[#4370] Fixes extlookup precedence getting overwritten between runs

We found the gsub! in extlookup was actually modifying the value for
extlookup_precedence, so the next node to call it just got the
interpolated value from the first run.

We did two things in the code to prevent this:
1. We returned a dup of the ast string object so that modifying it
wouldn’t change puppet’s state. We didn’t do this for all possible
return values because we depend on using the original ast array object
to do array concatenation
2. We fixed extlookup to not do a destructive gsub

Reviewed by: Jesse Wolfe

2 files changed, 1 insertions, 2 deletions

diff --git a/lib/puppet/parser/ast/function.rb b/lib/puppet/parser/ast/function.rb
index 602016c75..74023f631 100644
--- a/lib/puppet/parser/ast/function.rb
+++ b/lib/puppet/parser/ast/function.rb
@@ -11,7 +11,6 @@ class Puppet::Parser::AST
     @settor = true
 
     def evaluate(scope)
-
       # Make sure it's a defined function
       raise Puppet::ParseError, "Unknown function #{@name}" unless Puppet::Parser::Functions.function(@name)
 
diff --git a/lib/puppet/parser/ast/leaf.rb b/lib/puppet/parser/ast/leaf.rb
index 49cde63ca..090d75c4e 100644
--- a/lib/puppet/parser/ast/leaf.rb
+++ b/lib/puppet/parser/ast/leaf.rb
@@ -42,7 +42,7 @@ class Puppet::Parser::AST
   # The base string class.
   class String < AST::Leaf
     def evaluate(scope)
-      @value
+      @value.dup
     end
 
     def to_s