Fix dispatch when there are different receivers

with different numbers of arguments.
Fixes https://github.com/chef/chef-dk/issues/546)

2 files changed, 50 insertions, 4 deletions

diff --git a/lib/chef/event_dispatch/dispatcher.rb b/lib/chef/event_dispatch/dispatcher.rb
index 966a3f32ec..f3e55539a9 100644
--- a/lib/chef/event_dispatch/dispatcher.rb
+++ b/lib/chef/event_dispatch/dispatcher.rb
@@ -32,8 +32,11 @@ class Chef
           mth = s.method(method_name)
           # Trim arguments to match what the subscriber expects to allow
           # adding new arguments without breaking compat.
-          args = args.take(mth.arity) if mth.arity < args.size && mth.arity >= 0
-          mth.call(*args)
+          if mth.arity < args.size && mth.arity >= 0
+            mth.call(*args.take(mth.arity))
+          else
+            mth.call(*args)
+          end
         end
       end
 
diff --git a/spec/unit/event_dispatch/dispatcher_spec.rb b/spec/unit/event_dispatch/dispatcher_spec.rb
index 1014feea89..5a06e1d6d1 100644
--- a/spec/unit/event_dispatch/dispatcher_spec.rb
+++ b/spec/unit/event_dispatch/dispatcher_spec.rb
@@ -73,8 +73,51 @@ describe Chef::EventDispatch::Dispatcher do
         expect(event_sink.synchronized_cookbook_args).to eq ["apache2"]
       end
     end
-
   end
 
-end
 
+  context "when two event sinks have different arguments for an event" do
+    let(:event_sink_1) do
+      Class.new(Chef::EventDispatch::Base) do
+        attr_reader :synchronized_cookbook_args
+        def synchronized_cookbook(cookbook_name)
+          @synchronized_cookbook_args = [cookbook_name]
+        end
+      end.new
+    end
+    let(:event_sink_2) do
+      Class.new(Chef::EventDispatch::Base) do
+        attr_reader :synchronized_cookbook_args
+        def synchronized_cookbook(cookbook_name, cookbook)
+          @synchronized_cookbook_args = [cookbook_name, cookbook]
+        end
+      end.new
+    end
+
+    context "and the one with fewer arguments comes first" do
+      before do
+        dispatcher.register(event_sink_1)
+        dispatcher.register(event_sink_2)
+      end
+      it "trims the arugment list" do
+        cookbook_version = double("cookbook_version")
+        dispatcher.synchronized_cookbook("apache2", cookbook_version)
+        expect(event_sink_1.synchronized_cookbook_args).to eq ["apache2"]
+        expect(event_sink_2.synchronized_cookbook_args).to eq ["apache2", cookbook_version]
+      end
+    end
+
+    context "and the one with fewer arguments comes last" do
+      before do
+        dispatcher.register(event_sink_2)
+        dispatcher.register(event_sink_1)
+      end
+      it "trims the arugment list" do
+        cookbook_version = double("cookbook_version")
+        dispatcher.synchronized_cookbook("apache2", cookbook_version)
+        expect(event_sink_1.synchronized_cookbook_args).to eq ["apache2"]
+        expect(event_sink_2.synchronized_cookbook_args).to eq ["apache2", cookbook_version]
+      end
+    end
+  end
+end