Fix issue #3463: use real constants instead of const_missing

2 files changed, 41 insertions, 21 deletions

diff --git a/lib/chef/resource.rb b/lib/chef/resource.rb
index b8bf53d6ec..003683d66b 100644
--- a/lib/chef/resource.rb
+++ b/lib/chef/resource.rb
@@ -1274,31 +1274,48 @@ class Chef
       end
     end
 
-    # Implement deprecated LWRP class
-    module DeprecatedLWRPClass
-      # @api private
-      def register_deprecated_lwrp_class(resource_class, class_name)
-        if Chef::Resource.const_defined?(class_name, false)
-          Chef::Log.warn "#{class_name} already exists!  Cannot create deprecation class for #{resource_class}"
-        else
-          deprecated_constants[class_name.to_sym] = resource_class
+    # @api private
+    def self.register_deprecated_lwrp_class(resource_class, class_name)
+      if Chef::Resource.const_defined?(class_name, false)
+        Chef::Log.warn "#{class_name} already exists!  Deprecation class overwrites #{resource_class}"
+        Chef::Resource.send(:remove_const, class_name)
+      end
+      resource_subclass = class_eval <<-EOM, __FILE__, __LINE__+1
+        class Chef::Resource::#{class_name} < resource_class
+          def initialize(*args, &block)
+            Chef::Log.deprecation("Using an LWRP by its name (#{class_name}) directly is no longer supported in Chef 13 and will be removed.  Use Chef::Resource.resource_for_node(node, name) instead.")
+            super
+          end
+          self
+        end
+      EOM
+      # Make case, is_a and kind_of work with the new subclass, for backcompat
+      # Any subclass of Chef::Resource::ResourceClass is already a subclass of resource_class
+      # Any subclass of resource_class is considered a subclass of Chef::Resource::ResourceClass
+      resource_class.class_eval do
+        define_method(:is_a?) do |other|
+          other.is_a?(Module) && other === self
+        end
+        define_method(:kind_of?) do |other|
+          other.is_a?(Module) && other === self
         end
       end
-
-      def const_missing(class_name)
-        if deprecated_constants[class_name.to_sym]
+      resource_subclass.class_eval do
+        define_singleton_method(:===) do |other|
           Chef::Log.deprecation("Using an LWRP by its name (#{class_name}) directly is no longer supported in Chef 13 and will be removed.  Use Chef::Resource.resource_for_node(node, name) instead.")
-          deprecated_constants[class_name.to_sym]
-        else
-          raise NameError, "uninitialized constant Chef::Resource::#{class_name}"
+          # resource_subclass is a superclass of all resource_class descendants.
+          if self == resource_subclass && other.class <= resource_class
+            return true
+          end
+          super(other)
         end
       end
+      deprecated_constants[class_name.to_sym] = resource_subclass
+    end
 
-      def deprecated_constants
-        @deprecated_constants ||= {}
-      end
+    def self.deprecated_constants
+      @deprecated_constants ||= {}
     end
-    extend DeprecatedLWRPClass
 
     # @api private
     def lookup_provider_constant(name, action=:nothing)
diff --git a/lib/chef/resource/lwrp_base.rb b/lib/chef/resource/lwrp_base.rb
index 20d236a161..ea47ad4b06 100644
--- a/lib/chef/resource/lwrp_base.rb
+++ b/lib/chef/resource/lwrp_base.rb
@@ -58,7 +58,10 @@ class Chef
           resource_class.class_from_file(filename)
 
           # Make a useful string for the class (rather than <Class:312894723894>)
-          resource_class.instance_eval do
+          resource_class.class_eval do
+            define_method(:kind_of?)      { |other| other.class <= resource_class }
+            define_method(:is_a?)         { |other| other.class <= resource_class }
+
             define_singleton_method(:to_s) do
               "LWRP resource #{resource_name} from cookbook #{cookbook_name}"
             end
@@ -69,8 +72,8 @@ class Chef
 
           LWRPBase.loaded_lwrps[filename] = true
 
-          Chef::Resource.register_deprecated_lwrp_class(resource_class, convert_to_class_name(resource_name))
-
+          # Create the deprecated Chef::Resource::LwrpFoo class
+          resource_subclass = Chef::Resource.register_deprecated_lwrp_class(resource_class, convert_to_class_name(resource_name))
           resource_class
         end