4 files changed, 9 insertions, 9 deletions
diff --git a/lib/puppet/parser/functions/delete.rb b/lib/puppet/parser/functions/delete.rb
index f814344..d03a293 100644
--- a/lib/puppet/parser/functions/delete.rb
+++ b/lib/puppet/parser/functions/delete.rb
@@ -27,7 +27,7 @@ string, or key from a hash.
         "given #{arguments.size} for 2.")
     end
 
-    collection = arguments[0]
+    collection = arguments[0].dup
     item = arguments[1]
 
     case collection
diff --git a/lib/puppet/parser/functions/delete_undef_values.rb b/lib/puppet/parser/functions/delete_undef_values.rb
index 4eecab2..532639e 100644
--- a/lib/puppet/parser/functions/delete_undef_values.rb
+++ b/lib/puppet/parser/functions/delete_undef_values.rb
@@ -18,16 +18,16 @@ Would return: ['A','',false]
     raise(Puppet::ParseError,
           "delete_undef_values(): Wrong number of arguments given " +
           "(#{args.size})") if args.size < 1
-
-    result = args[0]
+    
+    unless args[0].is_a? Array or args[0].is_a? Hash 
+      raise(Puppet::ParseError,
+            "delete_undef_values(): expected an array or hash, got #{args[0]} type  #{args[0].class} ")
+    end
+    result = args[0].dup 
     if result.is_a?(Hash)
       result.delete_if {|key, val| val.equal? :undef}
     elsif result.is_a?(Array)
       result.delete :undef
-    else
-      raise(Puppet::ParseError, 
-            "delete_undef_values(): Wrong argument type #{args[0].class} " +
-            "for first argument")
     end
     result
   end
diff --git a/lib/puppet/parser/functions/delete_values.rb b/lib/puppet/parser/functions/delete_values.rb
index 17b9d37..ca8eef5 100644
--- a/lib/puppet/parser/functions/delete_values.rb
+++ b/lib/puppet/parser/functions/delete_values.rb
@@ -21,6 +21,6 @@ Would return: {'a'=>'A','c'=>'C','B'=>'D'}
       raise(TypeError, "delete_values(): First argument must be a Hash. " + \
                        "Given an argument of class #{hash.class}.") 
     end
-    hash.delete_if { |key, val| item == val }
+    hash.dup.delete_if { |key, val| item == val }
   end
 end
diff --git a/lib/puppet/parser/functions/pick.rb b/lib/puppet/parser/functions/pick.rb
index cbc0300..e9e5d66 100644
--- a/lib/puppet/parser/functions/pick.rb
+++ b/lib/puppet/parser/functions/pick.rb
@@ -21,7 +21,7 @@ EOS
    args.delete(:undefined)
    args.delete("")
    if args[0].to_s.empty? then
-     fail "Must provide non empty value."
+     fail Puppet::ParseError, "pick(): must receive at last one non empty value"
    else
      return args[0]
    end