Allow render tag to recognize drops that respond to to_partial

example/server/templates/index.liquid

@@ -1,5 +1,6 @@
 <p>Hello world!</p>
 
-<p>It is {{ date }}</p>
+<p>It is {{date}}</p>
 
-<p>Check out the <a href="/products">Products</a> screen</p>
+
+<p>Check out the <a href="/products">Products</a> screen </p>

lib/liquid/locales/en.yml

@@ -31,5 +31,6 @@
       variable_termination: "Variable '%{token}' was not properly terminated with regexp: %{tag_end}"
     argument:
       include: "Argument error in tag 'include' - Illegal template name"
+      render: "Argument error in tag 'render' - Dynamically chosen templates are not allowed"
     disabled:
       tag: "usage is not allowed in this context"

lib/liquid/snippet_drop.rb

@@ -2,11 +2,16 @@
 
 module Liquid
   class SnippetDrop < Drop
-    attr_reader :body
+    attr_reader :body, :name
 
-    def initialize(body)
+    def initialize(body, name)
       super()
       @body = body
+      @name = name
+    end
+
+    def to_partial
+      @body
     end
 
     def to_s

lib/liquid/tags/render.rb

@@ -47,40 +47,30 @@ module Liquid
     end
 
     def render_tag(context, output)
-      template_name = @template_name_expr
-      is_inline = template_name.is_a?(VariableLookup)
-      is_file = template_name.is_a?(String)
+      template = context.evaluate(@template_name_expr)
 
-      if is_inline
-        template_name = template_name.name
-        snippet_drop = context[template_name]
-        raise ::ArgumentError unless snippet_drop.is_a?(Liquid::SnippetDrop)
-
-        partial = snippet_drop.body
+      if template.respond_to?(:to_partial)
+        partial = template.to_partial
+        template_name = template.name
+      elsif @template_name_expr.is_a?(String)
+        partial = PartialCache.load(template, context: context, parse_context: parse_context)
+        template_name = partial.name
       else
-        raise ::ArgumentError unless is_file
-
-        partial = PartialCache.load(template_name, context: context, parse_context: parse_context)
+        raise ::ArgumentError, parse_context.locale.t("errors.argument.render")
       end
 
       context_variable_name = @alias_name || template_name.split('/').last
 
       render_partial_func = ->(var, forloop) {
-        inner_context = context.new_isolated_subcontext
-
-        if is_file
-          inner_context.template_name = partial.name
-          inner_context.partial = true
-        end
-
-        inner_context['forloop'] = forloop if forloop
+        inner_context               = context.new_isolated_subcontext
+        inner_context.template_name = template_name
+        inner_context.partial       = true
+        inner_context['forloop']    = forloop if forloop
 
         @attributes.each do |key, value|
           inner_context[key] = context.evaluate(value)
         end
-
         inner_context[context_variable_name] = var unless var.nil?
-
         partial.render_to_output_buffer(inner_context, output)
         forloop&.send(:increment!)
       }
@@ -113,7 +103,6 @@ module Liquid
         key = p.consume
         p.consume(:colon)
         @attributes[key] = safe_parse_expression(p)
-
         p.consume?(:comma) # optional comma
       end
 

lib/liquid/tags/snippet.rb

@@ -25,7 +25,7 @@ module Liquid
     end
 
     def render_to_output_buffer(context, output)
-      snippet_drop = SnippetDrop.new(@body)
+      snippet_drop = SnippetDrop.new(@body, @to)
       context.scopes.last[@to] = snippet_drop
 
       snippet_size = @body.nodelist.sum { |node| node.to_s.bytesize }

test/integration/tags/render_tag_test.rb

@@ -101,10 +101,11 @@ class RenderTagTest < Minitest::Test
     end
   end
 
-  def test_dynamically_choosen_templates_are_not_allowed
-    assert_raises(::ArgumentError) do
+  def test_dynamically_chosen_templates_are_not_allowed
+    error = assert_raises(::ArgumentError) do
       Template.parse('{% assign name = "snippet" %}{% render name %}').render!
     end
+    assert_equal("Argument error in tag 'render' - Dynamically chosen templates are not allowed", error.message)
   end
 
   def test_rigid_parsing_errors
@@ -296,6 +297,13 @@ class RenderTagTest < Minitest::Test
     )
   end
 
+  def test_render_tag_with_snippet_drop
+    assert_template_result(
+      "Hello from snippet",
+      "{% snippet my_snippet %}Hello from snippet{% endsnippet %}{% render my_snippet %}",
+    )
+  end
+
   def test_render_tag_renders_error_with_template_name
     assert_template_result(
       'Liquid error (foo line 1): standard error',