add global and per-resource toggles for resource cloning behavior

let us turn on and off resource cloning

6 files changed, 59 insertions, 2 deletions

diff --git a/chef-config/lib/chef-config/config.rb b/chef-config/lib/chef-config/config.rb
index c9c2ca77df..d66be1a749 100644
--- a/chef-config/lib/chef-config/config.rb
+++ b/chef-config/lib/chef-config/config.rb
@@ -1053,6 +1053,9 @@ module ChefConfig
 
     default :rubygems_url, "https://rubygems.org"
 
+    # For Chef-12 this is still the default, in Chef-13 the default will be false
+    default :resource_cloning, true
+
     # If installed via an omnibus installer, this gives the path to the
     # "embedded" directory which contains all of the software packaged with
     # omnibus. This is used to locate the cacert.pem file on windows.
diff --git a/lib/chef/mixin/notifying_block.rb b/lib/chef/mixin/notifying_block.rb
index 2d6a82f493..3ebb79ee7e 100644
--- a/lib/chef/mixin/notifying_block.rb
+++ b/lib/chef/mixin/notifying_block.rb
@@ -37,6 +37,9 @@ class Chef
         parent_context ||= @run_context
         sub_run_context = parent_context.create_child
 
+        # inhert the resource_cloning setting from our parent context
+        sub_run_context.resource_cloning = parent_context.resource_cloning
+
         begin
           outer_run_context = @run_context
           @run_context = sub_run_context
diff --git a/lib/chef/provider.rb b/lib/chef/provider.rb
index 40c31e4371..c2031712ec 100644
--- a/lib/chef/provider.rb
+++ b/lib/chef/provider.rb
@@ -342,6 +342,15 @@ class Chef
       include InlineResources
     end
 
+    # allow users to control enabling/disabling resource cloning per-resource
+    class << self
+      attr_accessor :resource_cloning
+
+      def resource_cloning(val)
+        @resource_cloning = val
+      end
+    end
+
     # Chef::Provider::InlineResources
     # Implementation of inline resource convergence for providers. See
     # Provider.use_inline_resources for a longer explanation.
@@ -358,6 +367,8 @@ class Chef
       def compile_and_converge_action(&block)
         old_run_context = run_context
         @run_context = run_context.create_child
+        # use_inline_resources gets the setting from the class instance variable
+        @run_context.resource_cloning = self.class.resource_cloning
         return_value = instance_eval(&block)
         Chef::Runner.new(run_context).converge
         return_value
diff --git a/lib/chef/resource_builder.rb b/lib/chef/resource_builder.rb
index 78b2fcd4d1..607e78358a 100644
--- a/lib/chef/resource_builder.rb
+++ b/lib/chef/resource_builder.rb
@@ -56,7 +56,7 @@ class Chef
       # This behavior is very counter-intuitive and should be removed.
       # See CHEF-3694, https://tickets.opscode.com/browse/CHEF-3694
       # Moved to this location to resolve CHEF-5052, https://tickets.opscode.com/browse/CHEF-5052
-      if prior_resource
+      if prior_resource && run_context.resource_cloning
         resource.load_from(prior_resource)
       end
 
@@ -80,7 +80,7 @@ class Chef
       end
 
       # emit a cloned resource warning if it is warranted
-      if prior_resource
+      if prior_resource && run_context.resource_cloning
         if is_trivial_resource?(prior_resource) && identicalish_resources?(prior_resource, resource)
           emit_harmless_cloning_debug
         else
diff --git a/lib/chef/run_context.rb b/lib/chef/run_context.rb
index aa6280e5be..511b64ed02 100644
--- a/lib/chef/run_context.rb
+++ b/lib/chef/run_context.rb
@@ -110,6 +110,11 @@ class Chef
     #
     attr_reader :audits
 
+    # Toggle to enable/disable resource cloning
+    #
+    # @return [Boolean] True if resource cloning is enabled for this run_context
+    attr_accessor :resource_cloning
+
     #
     # Notification handling
     #
@@ -192,6 +197,7 @@ class Chef
     #
     def initialize_child_state
       @audits = {}
+      @resource_cloning = Chef::Config[:resource_cloning]
       @resource_collection = Chef::ResourceCollection.new(self)
       @before_notification_collection = Hash.new { |h, k| h[k] = [] }
       @immediate_notification_collection = Hash.new { |h, k| h[k] = [] }
@@ -651,6 +657,8 @@ ERROR_MESSAGE
         delayed_notification_collection
         delayed_notification_collection=
         delayed_notifications
+        resource_cloning
+        resource_cloning=
         immediate_notification_collection
         immediate_notification_collection=
         immediate_notifications
diff --git a/spec/unit/recipe_spec.rb b/spec/unit/recipe_spec.rb
index eea1a41998..e1e3e0ad72 100644
--- a/spec/unit/recipe_spec.rb
+++ b/spec/unit/recipe_spec.rb
@@ -193,6 +193,38 @@ describe Chef::Recipe do
       end
     end
 
+    describe "when resource cloning is disabled" do
+      def not_expect_warning
+        expect(Chef::Log).not_to receive(:warn).with(/3694/)
+        expect(Chef::Log).not_to receive(:warn).with(/Previous/)
+        expect(Chef::Log).not_to receive(:warn).with(/Current/)
+      end
+
+      before do
+        Chef::Config[:resource_cloning] = false
+      end
+
+      it "should emit a 3694 warning when attributes change" do
+        recipe.zen_master "klopp" do
+          something "bvb"
+        end
+        not_expect_warning
+        recipe.zen_master "klopp" do
+          something "vbv"
+        end
+      end
+
+      it "should not copy attributes from a prior resource" do
+        recipe.zen_master "klopp" do
+          something "bvb"
+        end
+        not_expect_warning
+        recipe.zen_master "klopp"
+        expect(run_context.resource_collection.first.something).to eql("bvb")
+        expect(run_context.resource_collection[1].something).to be nil
+      end
+    end
+
     describe "when cloning resources" do
       def expect_warning
         expect(Chef).to receive(:deprecated).with(:resource_cloning, /^Cloning resource attributes for zen_master\[klopp\]/)