Optimize Jekyll::Filters#item_property (#7696)

Merge pull request 7696

.rubocop.yml

@@ -79,6 +79,8 @@ Metrics/MethodLength:
   Severity: error
 Metrics/ModuleLength:
   Max: 240
+  Exclude:
+    - lib/jekyll/filters.rb
 Metrics/ParameterLists:
   Max: 4
 Metrics/PerceivedComplexity:

lib/jekyll/filters.rb

@@ -356,15 +356,24 @@ module Jekyll
       @item_property_cache ||= {}
       @item_property_cache[property] ||= {}
       @item_property_cache[property][item] ||= begin
-        if item.respond_to?(:to_liquid)
-          property.to_s.split(".").reduce(item.to_liquid) do |subvalue, attribute|
-            parse_sort_input(subvalue[attribute])
-          end
+        property = property.to_s
+        property = if item.respond_to?(:to_liquid)
+                     read_liquid_attribute(item.to_liquid, property)
                    elsif item.respond_to?(:data)
-          parse_sort_input(item.data[property.to_s])
+                     item.data[property]
                    else
-          parse_sort_input(item[property.to_s])
+                     item[property]
                    end
+
+        parse_sort_input(property)
+      end
+    end
+
+    def read_liquid_attribute(liquid_data, property)
+      return liquid_data[property] unless property.include?(".")
+
+      property.split(".").reduce(liquid_data) do |data, key|
+        data.respond_to?(:[]) && data[key]
       end
     end