Supporting a nil expirer on cacher objects.

This works for those classes like Puppet::Type that use an expirer that isn't
always present (they use their catalog as an expirer).

The behaviour is now that if there is no expirer, expire() is a no-op and all
data is considered expired all the time, so it's always fresh.

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

2 files changed, 23 insertions, 1 deletions

diff --git a/lib/puppet/util/cacher.rb b/lib/puppet/util/cacher.rb
index c1b3bad7a..a9fb890c6 100644
--- a/lib/puppet/util/cacher.rb
+++ b/lib/puppet/util/cacher.rb
@@ -59,7 +59,14 @@ module Puppet::Util::Cacher
     # Methods that get added to instances.
     module InstanceMethods
         def expire
-            expirer.expire
+            # Only expire if we have an expirer.  This is
+            # mostly so that we can comfortably handle cases
+            # like Puppet::Type instances, which use their
+            # catalog as their expirer, and they often don't
+            # have a catalog.
+            if e = expirer
+                e.expire
+            end
         end
 
         def expirer
diff --git a/spec/unit/util/cacher.rb b/spec/unit/util/cacher.rb
index 3e8d31a24..5a867c6c1 100755
--- a/spec/unit/util/cacher.rb
+++ b/spec/unit/util/cacher.rb
@@ -79,6 +79,21 @@ describe Puppet::Util::Cacher do
             @object.instance_cache.should_not equal(value)
         end
 
+        it "should be able to trigger expiration on its expirer" do
+            @expirer.expects(:expire)
+            @object.expire
+        end
+
+        it "should do nothing when asked to expire when no expirer is available" do
+            cacher = CacheTest.new
+            class << cacher
+                def expirer
+                    nil
+                end
+            end
+            lambda { cacher.expire }.should_not raise_error
+        end
+
         it "should be able to cache false values" do
             @object.expects(:init_instance_cache).returns false
             @object.instance_cache.should be_false