Allowing a nil expirer for caching classes.

If there's no expirer, then the value is regenerated every
time.

Signed-off-by: Luke Kanies <luke@madstop.com>

lib/puppet/util/cacher.rb

@@ -70,7 +70,8 @@ module Puppet::Util::Cacher
         end
 
         def cached_value(name)
-            if expirer.expired?(cache_timestamp)
+            # Allow a nil expirer, in which case we regenerate the value every time.
+            if expirer.nil? or expirer.expired?(cache_timestamp)
                 value_cache.clear
                 @cache_timestamp = Time.now
             end

spec/unit/util/cacher.rb

@@ -51,7 +51,7 @@ describe Puppet::Util::Cacher do
         CacheTest.new.expirer.should equal(Puppet::Util::Cacher)
     end
 
-    describe "when defining cached attributes" do
+    describe "when using cached attributes" do
         before do
             @expirer = ExpirerTest.new
             @object = CacheTest.new
@@ -90,5 +90,10 @@ describe Puppet::Util::Cacher do
             @expirer.expire
             @object.instance_cache.should equal(@object.instance_cache)
         end
+
+        it "should always consider a value expired if it has no expirer" do
+            @object.stubs(:expirer).returns nil
+            @object.instance_cache.should_not equal(@object.instance_cache)
+        end
     end
 end