Merge pull request #258 from myabc/fix/render-nil-scope

Ruby 2.2: Tilt::HamlTemplate#render shouldn't blow up on explicit nil

lib/tilt/haml.rb

@@ -13,6 +13,8 @@ def prepare
     end
 
     def evaluate(scope, locals, &block)
+      raise ArgumentError, 'invalid scope: must not be frozen' if scope.frozen?
+
       if @engine.respond_to?(:precompiled_method_return_value, true)
         super
       else
@@ -54,4 +56,3 @@ def precompiled_postamble(locals)
     end
   end
 end
-

lib/tilt/template.rb

@@ -92,7 +92,8 @@ def initialize(file=nil, line=1, options={}, &block)
     # Render the template in the given scope with the locals specified. If a
     # block is given, it is typically available within the template via
     # +yield+.
-    def render(scope=Object.new, locals={}, &block)
+    def render(scope=nil, locals={}, &block)
+      scope ||= Object.new
       current_template = Thread.current[:tilt_current_template]
       Thread.current[:tilt_current_template] = self
       evaluate(scope, locals || {}, &block)

test/tilt_hamltemplate_test.rb

@@ -27,6 +27,17 @@ class HamlTemplateTest < Minitest::Test
       assert_equal "<p>Hey Joe!</p>\n", template.render(Object.new, :name => 'Joe')
     end
 
+    test 'evaluating in default/nil scope' do
+      template = Tilt::HamlTemplate.new { |t| '%p Hey unknown!' }
+      assert_equal "<p>Hey unknown!</p>\n", template.render
+      assert_equal "<p>Hey unknown!</p>\n", template.render(nil)
+    end
+
+    test 'evaluating in invalid, frozen scope' do
+      template = Tilt::HamlTemplate.new { |t| '%p Hey unknown!' }
+      assert_raises(ArgumentError) { template.render(Object.new.freeze) }
+    end
+
     test "evaluating in an object scope" do
       template = Tilt::HamlTemplate.new { "%p= 'Hey ' + @name + '!'" }
       scope = Object.new
@@ -87,6 +98,17 @@ class Scope
       assert_equal "<p>Hey Joe!</p>\n", template.render(Scope.new, :name => 'Joe')
     end
 
+    test 'evaluating in default/nil scope' do
+      template = Tilt::HamlTemplate.new { |t| '%p Hey unknown!' }
+      assert_equal "<p>Hey unknown!</p>\n", template.render
+      assert_equal "<p>Hey unknown!</p>\n", template.render(nil)
+    end
+
+    test 'evaluating in invalid, frozen scope' do
+      template = Tilt::HamlTemplate.new { |t| '%p Hey unknown!' }
+      assert_raises(ArgumentError) { template.render(Object.new.freeze) }
+    end
+
     test "evaluating in an object scope" do
       template = Tilt::HamlTemplate.new { "%p= 'Hey ' + @name + '!'" }
       scope = Scope.new

test/tilt_template_test.rb

@@ -122,6 +122,12 @@ def evaluate(scope, locals, &block)
     assert inst.prepared?
   end
 
+  test 'prepares and evaluates the template on #render with nil arg' do
+    inst = SimpleMockTemplate.new { |t| "Hello World!" }
+    assert_equal '<em>Hello World!</em>', inst.render(nil)
+    assert inst.prepared?
+  end
+
   class SourceGeneratingMockTemplate < PreparingMockTemplate
     def precompiled_template(locals)
       "foo = [] ; foo << %Q{#{data}} ; foo.join"