Drop the setter methods cache in favour of respond_to? (see #472)

lib/her/model/attributes.rb

@@ -55,9 +55,19 @@ def method_missing(method, *args, &blk)
 
       # @private
       def respond_to_missing?(method, include_private = false)
+        return false if Thread.current[:her_respond_to_missing]
         method.to_s =~ /[?=]$/ || @_her_attributes.include?(method) || super
       end
 
+      def respond_to_without_missing?(method, include_private = false)
+        Thread.current[:her_respond_to_missing] = true
+        respond_to?(method, include_private)
+      ensure
+        # Normally we would use nil to delete the variable but this is
+        # slightly more expensive and performance counts here.
+        Thread.current[:her_respond_to_missing] = false
+      end
+
       # Assign new attributes to a resource
       #
       # @example
@@ -201,10 +211,9 @@ def use_setter_methods(model, params = {})
           reserved = [:id, model.class.primary_key, *model.class.association_keys]
           model.class.attributes *params.keys.reject { |k| reserved.include?(k) }
 
-          setter_method_names = model.class.setter_method_names
           params.each_with_object({}) do |(key, value), memo|
             setter_method = "#{key}="
-            if setter_method_names.include?(setter_method)
+            if model.respond_to_without_missing?(setter_method)
               model.send setter_method, value
             else
               memo[key.to_sym] = value
@@ -278,15 +287,6 @@ def store_metadata(value = nil)
           store_her_data(:metadata, value)
         end
 
-        # @private
-        def setter_method_names
-          @_her_setter_method_names ||= begin
-            instance_methods.each_with_object(Set.new) do |method, memo|
-              memo << method.to_s if method.to_s.end_with?('=')
-            end
-          end
-        end
-
         private
 
         # @private

spec/model/attributes_spec.rb

@@ -242,6 +242,18 @@ def document=(document)
         @user = Foo::User.find(1)
         expect(@user.document).to eq("http://example.com")
       end
+
+      it 'exposes the method to respond_to? and respond_to_without_missing?' do
+        @user = Foo::User.find(1)
+        expect(@user.respond_to?(:document=)).to be_truthy
+        expect(@user.respond_to_without_missing?(:document=)).to be_truthy
+      end
+
+      it 'exposes a non-existent method to respond_to? but not respond_to_without_missing?' do
+        @user = Foo::User.find(1)
+        expect(@user.respond_to?(:nonexistent=)).to be_truthy
+        expect(@user.respond_to_without_missing?(:nonexistent=)).to be_falsey
+      end
     end
 
     context "for predicate method" do