Wrap partial lookups to override for tracking

* Allow render to handle with and for correctly

* code improvements

lib/liquid/tags/include.rb

@@ -50,19 +50,7 @@ module Liquid
       template_name = context.evaluate(@template_name_expr)
       raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name
 
-      partial = PartialCache.load(
-        template_name,
-        context: context,
-        parse_context: parse_context
-      )
-
-      context_variable_name = @alias_name || template_name.split('/').last
-
-      variable = if @variable_name_expr
-        context.evaluate(@variable_name_expr)
-      else
-        context.find_variable(template_name, raise_on_not_found: false)
-      end
+      partial = load_partial(template_name, context, parse_context)
 
       old_template_name = context.template_name
       old_partial       = context.partial
@@ -71,7 +59,15 @@ module Liquid
         context.partial       = true
         context.stack do
           @attributes.each do |key, value|
-            context[key] = context.evaluate(value)
+            context[key] = evaluate(context, value)
+          end
+
+          context_variable_name = @alias_name || template_name.split('/').last
+
+          variable = if @variable_name_expr
+            evaluate(context, @variable_name_expr)
+          else
+            find_variable(context, template_name, raise_on_not_found: false)
           end
 
           if variable.is_a?(Array)
@@ -103,6 +99,24 @@ module Liquid
         ] + @node.attributes.values
       end
     end
+
+    private
+
+    def evaluate(context, value)
+      context.evaluate(value)
+    end
+
+    def find_variable(context, *args)
+      context.find_variable(*args)
+    end
+
+    def load_partial(template_name, context, parse_context)
+      PartialCache.load(
+        template_name,
+        context: context,
+        parse_context: parse_context
+      )
+    end
   end
 
   Template.register_tag('include', Include)

lib/liquid/tags/render.rb

@@ -2,7 +2,8 @@
 
 module Liquid
   class Render < Tag
-    SYNTAX = /(#{QuotedString}+)(\s+(?:with|for)\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
+    FOR = 'for'
+    SYNTAX = /(#{QuotedString}+)(\s+(with|#{FOR})\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
 
     disable_tags "include"
 
@@ -14,11 +15,13 @@ module Liquid
       raise SyntaxError, options[:locale].t("errors.syntax.render") unless markup =~ SYNTAX
 
       template_name = Regexp.last_match(1)
-      variable_name = Regexp.last_match(3)
+      with_or_for = Regexp.last_match(3)
+      variable_name = Regexp.last_match(4)
 
-      @alias_name = Regexp.last_match(5)
+      @alias_name = Regexp.last_match(6)
       @variable_name_expr = variable_name ? Expression.parse(variable_name) : nil
       @template_name_expr = Expression.parse(template_name)
+      @for = (with_or_for == FOR)
 
       @attributes = {}
       markup.scan(TagAttributes) do |key, value|
@@ -35,11 +38,7 @@ module Liquid
       template_name = context.evaluate(@template_name_expr)
       raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name
 
-      partial = PartialCache.load(
-        template_name,
-        context: context,
-        parse_context: parse_context
-      )
+      partial = load_partial(template_name, context, parse_context)
 
       context_variable_name = @alias_name || template_name.split('/').last
 
@@ -50,15 +49,15 @@ module Liquid
         inner_context['forloop']    = forloop if forloop
 
         @attributes.each do |key, value|
-          inner_context[key] = context.evaluate(value)
+          inner_context[key] = evaluate(context, value)
         end
         inner_context[context_variable_name] = var unless var.nil?
         partial.render_to_output_buffer(inner_context, output)
         forloop&.send(:increment!)
       }
 
-      variable = @variable_name_expr ? context.evaluate(@variable_name_expr) : nil
-      if variable.is_a?(Array)
+      variable = @variable_name_expr ? evaluate(context, @variable_name_expr) : nil
+      if @for && variable.respond_to?(:each) && variable.respond_to?(:count)
         forloop = Liquid::ForloopDrop.new(template_name, variable.count, nil)
         variable.each { |var| render_partial_func.call(var, forloop) }
       else
@@ -75,6 +74,20 @@ module Liquid
         ] + @node.attributes.values
       end
     end
+
+    private
+
+    def evaluate(context, value)
+      context.evaluate(value)
+    end
+
+    def load_partial(template_name, context, parse_context)
+      PartialCache.load(
+        template_name,
+        context: context,
+        parse_context: parse_context
+      )
+    end
   end
 
   Template.register_tag('render', Render)

test/integration/tags/render_tag_test.rb

@@ -214,4 +214,22 @@ class RenderTagTest < Minitest::Test
     assert_template_result("Product: Draft 151cm first  index:1 Product: Element 155cm  last index:2 ",
                            "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
+
+  def test_render_tag_for_drop
+    Liquid::Template.file_system = StubFileSystem.new(
+      'loop' => "{{ value.foo }}",
+    )
+
+    assert_template_result("123",
+                           "{% render 'loop' for loop as value %}", "loop" => TestEnumerable.new)
+  end
+
+  def test_render_tag_with_drop
+    Liquid::Template.file_system = StubFileSystem.new(
+      'loop' => "{{ value }}",
+    )
+
+    assert_template_result("TestEnumerable",
+                           "{% render 'loop' with loop as value %}", "loop" => TestEnumerable.new)
+  end
 end