Merge pull request #1524 from Shopify/global-constant-cache

Eagerly cache global filters

lib/liquid.rb

@@ -59,8 +59,8 @@ require 'liquid/forloop_drop'
 require 'liquid/extensions'
 require 'liquid/errors'
 require 'liquid/interrupts'
-require 'liquid/strainer_factory'
 require 'liquid/strainer_template'
+require 'liquid/strainer_factory'
 require 'liquid/expression'
 require 'liquid/context'
 require 'liquid/parser_switching'

lib/liquid/strainer_factory.rb

@@ -7,25 +7,26 @@ module Liquid
 
     def add_global_filter(filter)
       strainer_class_cache.clear
-      global_filters << filter
+      GlobalCache.add_filter(filter)
     end
 
     def create(context, filters = [])
       strainer_from_cache(filters).new(context)
     end
 
+    GlobalCache = Class.new(StrainerTemplate)
+
     private
 
-    def global_filters
-      @global_filters ||= []
-    end
-
     def strainer_from_cache(filters)
-      strainer_class_cache[filters] ||= begin
-        klass = Class.new(StrainerTemplate)
-        global_filters.each { |f| klass.add_filter(f) }
-        filters.each { |f| klass.add_filter(f) }
-        klass
+      if filters.empty?
+        GlobalCache
+      else
+        strainer_class_cache[filters] ||= begin
+          klass = Class.new(GlobalCache)
+          filters.each { |f| klass.add_filter(f) }
+          klass
+        end
       end
     end
 

lib/liquid/strainer_template.rb

@@ -31,6 +31,11 @@ module Liquid
         filter_methods.include?(method.to_s)
       end
 
+      def inherited(subclass)
+        super
+        subclass.instance_variable_set(:@filter_methods, @filter_methods.dup)
+      end
+
       private
 
       def filter_methods

test/test_helper.rb

@@ -72,21 +72,21 @@ module Minitest
     end
 
     def with_global_filter(*globals)
-      original_global_filters = Liquid::StrainerFactory.instance_variable_get(:@global_filters)
-      Liquid::StrainerFactory.instance_variable_set(:@global_filters, [])
-      globals.each do |global|
-        Liquid::StrainerFactory.add_global_filter(global)
-      end
-
-      Liquid::StrainerFactory.send(:strainer_class_cache).clear
+      original_global_cache = Liquid::StrainerFactory::GlobalCache
+      Liquid::StrainerFactory.send(:remove_const, :GlobalCache)
+      Liquid::StrainerFactory.const_set(:GlobalCache, Class.new(Liquid::StrainerTemplate))
 
       globals.each do |global|
         Liquid::Template.register_filter(global)
       end
-      yield
-    ensure
       Liquid::StrainerFactory.send(:strainer_class_cache).clear
-      Liquid::StrainerFactory.instance_variable_set(:@global_filters, original_global_filters)
+      begin
+        yield
+      ensure
+        Liquid::StrainerFactory.send(:remove_const, :GlobalCache)
+        Liquid::StrainerFactory.const_set(:GlobalCache, original_global_cache)
+        Liquid::StrainerFactory.send(:strainer_class_cache).clear
+      end
     end
 
     def with_error_mode(mode)

test/unit/strainer_factory_unit_test.rb

@@ -52,7 +52,8 @@ class StrainerFactoryUnitTest < Minitest::Test
       /\ALiquid error: wrong number of arguments \((1 for 0|given 1, expected 0)\)\z/,
       exception.message
     )
-    assert_equal(exception.backtrace[0].split(':')[0], __FILE__)
+    source = AccessScopeFilters.instance_method(:public_filter).source_location
+    assert_equal(source.map(&:to_s), exception.backtrace[0].split(':')[0..1])
   end
 
   def test_strainer_only_invokes_public_filter_methods

test/unit/strainer_template_unit_test.rb

@@ -57,8 +57,8 @@ class StrainerTemplateUnitTest < Minitest::Test
   end
 
   def test_add_filter_does_not_raise_when_module_overrides_previously_registered_method
-    strainer = Context.new.strainer
     with_global_filter do
+      strainer = Context.new.strainer
       strainer.class.add_filter(PublicMethodOverrideFilter)
       assert(strainer.class.send(:filter_methods).include?('public_filter'))
     end