diff --git a/lib/puppet/parser/functions.rb b/lib/puppet/parser/functions.rb
index 22eee70d7..64f2eb8b7 100644
--- a/lib/puppet/parser/functions.rb
+++ b/lib/puppet/parser/functions.rb
@@ -1,122 +1,122 @@
 require 'puppet/util/autoload'
 require 'puppet/parser/scope'
 require 'monitor'
 
 # A module for managing parser functions.  Each specified function
 # is added to a central module that then gets included into the Scope
 # class.
 module Puppet::Parser::Functions
 
   (@functions = Hash.new { |h,k| h[k] = {} }).extend(MonitorMixin)
   (@modules   = {}                          ).extend(MonitorMixin)
 
   class << self
     include Puppet::Util
   end
 
   def self.autoloader
     unless defined?(@autoloader)
       @autoloader = Puppet::Util::Autoload.new(
         self,
         "puppet/parser/functions",
         :wrap => false
       )
     end
 
     @autoloader
   end
 
   Environment = Puppet::Node::Environment
 
   def self.environment_module(env = nil)
     if env and ! env.is_a?(Puppet::Node::Environment)
       env = Puppet::Node::Environment.new(env)
     end
     @modules.synchronize {
       @modules[ (env || Environment.current || Environment.root).name ] ||= Module.new
     }
   end
 
   # Create a new function type.
   def self.newfunction(name, options = {}, &block)
     name = symbolize(name)
 
-    raise Puppet::DevError, "Function #{name} already defined" if functions.include?(name)
+    Puppet.warning "Overwriting previous definition for function #{name}" if functions.include?(name)
 
     ftype = options[:type] || :statement
 
     unless ftype == :statement or ftype == :rvalue
       raise Puppet::DevError, "Invalid statement type #{ftype.inspect}"
     end
 
     fname = "function_#{name}"
     environment_module.send(:define_method, fname, &block)
 
     # Someday we'll support specifying an arity, but for now, nope
     #functions[name] = {:arity => arity, :type => ftype}
     functions[name] = {:type => ftype, :name => fname}
     functions[name][:doc] = options[:doc] if options[:doc]
   end
 
   # Remove a function added by newfunction
   def self.rmfunction(name)
     name = symbolize(name)
 
     raise Puppet::DevError, "Function #{name} is not defined" unless functions.include? name
 
     functions.delete name
 
     fname = "function_#{name}"
     environment_module.send(:remove_method, fname)
   end
 
   # Determine if a given name is a function
   def self.function(name)
     name = symbolize(name)
 
     @functions.synchronize do
       unless functions.include?(name) or functions(Puppet::Node::Environment.root).include?(name)
         autoloader.load(name,Environment.current || Environment.root)
       end
     end
 
     ( functions(Environment.root)[name] || functions[name] || {:name => false} )[:name]
   end
 
   def self.functiondocs
     autoloader.loadall
 
     ret = ""
 
     functions.sort { |a,b| a[0].to_s <=> b[0].to_s }.each do |name, hash|
       ret += "#{name}\n#{"-" * name.to_s.length}\n"
       if hash[:doc]
         ret += Puppet::Util::Docs.scrub(hash[:doc])
       else
         ret += "Undocumented.\n"
       end
 
       ret += "\n\n- *Type*: #{hash[:type]}\n\n"
     end
 
     ret
   end
 
   def self.functions(env = nil)
     @functions.synchronize {
       @functions[ env || Environment.current || Environment.root ]
     }
   end
 
   # Determine if a given function returns a value or not.
   def self.rvalue?(name)
     (functions[symbolize(name)] || {})[:type] == :rvalue
   end
 
   # Runs a newfunction to create a function for each of the log levels
   Puppet::Util::Log.levels.each do |level|
     newfunction(level, :doc => "Log a message on the server at level #{level.to_s}.") do |vals|
       send(level, vals.join(" "))
     end
   end
 end
diff --git a/spec/unit/parser/functions_spec.rb b/spec/unit/parser/functions_spec.rb
index 7eb6f299b..bd453402d 100755
--- a/spec/unit/parser/functions_spec.rb
+++ b/spec/unit/parser/functions_spec.rb
@@ -1,105 +1,106 @@
 #!/usr/bin/env rspec
 require 'spec_helper'
 
 describe Puppet::Parser::Functions do
 
   after(:each) do
     # Rationale:
     # our various tests will almost all register to Pupet::Parser::Functions
     # a new function called "name". All tests are required to stub Puppet::Parser::Scope
     # so that +no+ new real ruby method are defined.
     # After each test, we want to leave the whole Puppet::Parser::Functions environment
     # as it was before we were called, hence we call rmfunction (which might not succeed
     # if the function hasn't been registered in the test). It is also important in this
     # section to stub +remove_method+ here so that we don't pollute the scope.
     Puppet::Parser::Scope.stubs(:remove_method)
     begin
       Puppet::Parser::Functions.rmfunction("name")
     rescue
     end
   end
 
   it "should have a method for returning an environment-specific module" do
     Puppet::Parser::Functions.environment_module(Puppet::Node::Environment.new("myenv")).should be_instance_of(Module)
   end
 
   it "should use the current default environment if no environment is provided" do
     Puppet::Parser::Functions.environment_module.should be_instance_of(Module)
   end
 
   it "should be able to retrieve environment modules asked for by name rather than instance" do
     Puppet::Parser::Functions.environment_module(Puppet::Node::Environment.new("myenv")).should equal(Puppet::Parser::Functions.environment_module("myenv"))
   end
 
   describe "when calling newfunction" do
     before do
       @module = Module.new
       Puppet::Parser::Functions.stubs(:environment_module).returns @module
     end
 
     it "should create the function in the environment module" do
       @module.expects(:define_method).with { |name,block| name == "function_name" }
 
       Puppet::Parser::Functions.newfunction("name", :type => :rvalue)
     end
 
-    it "should raise an error if the function already exists" do
-      @module.expects(:define_method).with { |name,block| name == "function_name" }.once
+    it "should warn if the function already exists" do
+      @module.expects(:define_method).with { |name,block| name == "function_name" }.twice
       Puppet::Parser::Functions.newfunction("name", :type => :rvalue)
+      Puppet.expects(:warning)
 
-      lambda { Puppet::Parser::Functions.newfunction("name", :type => :rvalue) }.should raise_error
+      Puppet::Parser::Functions.newfunction("name", :type => :rvalue)
     end
 
     it "should raise an error if the function type is not correct" do
       @module.expects(:define_method).with { |name,block| name == "function_name" }.never
 
       lambda { Puppet::Parser::Functions.newfunction("name", :type => :unknown) }.should raise_error
     end
   end
 
   describe "when calling rmfunction" do
     before do
       @module = Module.new
       Puppet::Parser::Functions.stubs(:environment_module).returns @module
     end
 
     it "should remove the function in the scope class" do
       @module.expects(:define_method).with { |name,block| name == "function_name" }
       Puppet::Parser::Functions.newfunction("name", :type => :rvalue)
 
       @module.expects(:remove_method).with("function_name").once
 
       Puppet::Parser::Functions.rmfunction("name")
     end
 
     it "should raise an error if the function doesn't exists" do
       lambda { Puppet::Parser::Functions.rmfunction("name") }.should raise_error
     end
   end
 
   describe "when calling function to test function existance" do
     before do
       @module = Module.new
       Puppet::Parser::Functions.stubs(:environment_module).returns @module
     end
 
     it "should return false if the function doesn't exist" do
       Puppet::Parser::Functions.autoloader.stubs(:load)
 
       Puppet::Parser::Functions.function("name").should be_false
     end
 
     it "should return its name if the function exists" do
       @module.expects(:define_method).with { |name,block| name == "function_name" }
       Puppet::Parser::Functions.newfunction("name", :type => :rvalue)
 
       Puppet::Parser::Functions.function("name").should == "function_name"
     end
 
     it "should try to autoload the function if it doesn't exist yet" do
       Puppet::Parser::Functions.autoloader.expects(:load)
 
       Puppet::Parser::Functions.function("name")
     end
   end
 end