Remove support for taint_mode on ruby versions that don't support it

lib/liquid/template.rb

@@ -69,7 +69,14 @@ module Liquid
       # :lax is the default, and ignores the taint flag completely
       # :warn adds a warning, but does not interrupt the rendering
       # :error raises an error when tainted output is used
-      attr_writer :taint_mode
+      # @deprecated Since it is being deprecated in ruby itself.
+      def taint_mode=(mode)
+        taint_supported = Object.new.taint.tainted?
+        if mode != :lax && !taint_supported
+          raise NotImplementedError, "#{RUBY_ENGINE} #{RUBY_VERSION} doesn't support taint checking"
+        end
+        @taint_mode = mode
+      end
 
       attr_accessor :default_exception_renderer
       Template.default_exception_renderer = lambda do |exception|

lib/liquid/variable.rb

@@ -143,8 +143,8 @@ module Liquid
     end
 
     def taint_check(context, obj)
-      return unless obj.tainted?
       return if Template.taint_mode == :lax
+      return unless obj.tainted?
 
       @markup =~ QuotedFragment
       name = Regexp.last_match(0)

test/integration/drop_test.rb

@@ -114,29 +114,31 @@ class DropsTest < Minitest::Test
     assert_equal('  ', tpl.render!('product' => ProductDrop.new))
   end
 
-  def test_rendering_raises_on_tainted_attr
-    with_taint_mode(:error) do
-      tpl = Liquid::Template.parse('{{ product.user_input }}')
-      assert_raises TaintedError do
-        tpl.render!('product' => ProductDrop.new)
+  if taint_supported?
+    def test_rendering_raises_on_tainted_attr
+      with_taint_mode(:error) do
+        tpl = Liquid::Template.parse('{{ product.user_input }}')
+        assert_raises TaintedError do
+          tpl.render!('product' => ProductDrop.new)
+        end
       end
     end
-  end
 
-  def test_rendering_warns_on_tainted_attr
-    with_taint_mode(:warn) do
-      tpl     = Liquid::Template.parse('{{ product.user_input }}')
-      context = Context.new('product' => ProductDrop.new)
-      tpl.render!(context)
-      assert_equal [Liquid::TaintedError], context.warnings.map(&:class)
-      assert_equal "variable 'product.user_input' is tainted and was not escaped", context.warnings.first.to_s(false)
+    def test_rendering_warns_on_tainted_attr
+      with_taint_mode(:warn) do
+        tpl     = Liquid::Template.parse('{{ product.user_input }}')
+        context = Context.new('product' => ProductDrop.new)
+        tpl.render!(context)
+        assert_equal [Liquid::TaintedError], context.warnings.map(&:class)
+        assert_equal "variable 'product.user_input' is tainted and was not escaped", context.warnings.first.to_s(false)
+      end
     end
-  end
 
-  def test_rendering_doesnt_raise_on_escaped_tainted_attr
-    with_taint_mode(:error) do
-      tpl = Liquid::Template.parse('{{ product.user_input | escape }}')
-      tpl.render!('product' => ProductDrop.new)
+    def test_rendering_doesnt_raise_on_escaped_tainted_attr
+      with_taint_mode(:error) do
+        tpl = Liquid::Template.parse('{{ product.user_input | escape }}')
+        tpl.render!('product' => ProductDrop.new)
+      end
     end
   end
 

test/integration/tags/render_tag_test.rb

@@ -42,29 +42,31 @@ class RenderTagTest < Minitest::Test
     assert_template_result('', "{% assign snippet = 'should not be visible' %}{% render 'snippet' %}")
   end
 
-  def test_render_sets_the_correct_template_name_for_errors
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ unsafe }}')
+  if taint_supported?
+    def test_render_sets_the_correct_template_name_for_errors
+      Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ unsafe }}')
 
-    with_taint_mode :error do
-      template = Liquid::Template.parse('{% render "snippet", unsafe: unsafe %}')
-      context  = Context.new('unsafe' => (+'unsafe').tap(&:taint))
-      template.render(context)
+      with_taint_mode :error do
+        template = Liquid::Template.parse('{% render "snippet", unsafe: unsafe %}')
+        context  = Context.new('unsafe' => (+'unsafe').tap(&:taint))
+        template.render(context)
 
-      assert_equal [Liquid::TaintedError], template.errors.map(&:class)
-      assert_equal 'snippet', template.errors.first.template_name
+        assert_equal [Liquid::TaintedError], template.errors.map(&:class)
+        assert_equal 'snippet', template.errors.first.template_name
+      end
     end
-  end
 
-  def test_render_sets_the_correct_template_name_for_warnings
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ unsafe }}')
+    def test_render_sets_the_correct_template_name_for_warnings
+      Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ unsafe }}')
 
-    with_taint_mode :warn do
-      template = Liquid::Template.parse('{% render "snippet", unsafe: unsafe %}')
-      context  = Context.new('unsafe' => (+'unsafe').tap(&:taint))
-      template.render(context)
+      with_taint_mode :warn do
+        template = Liquid::Template.parse('{% render "snippet", unsafe: unsafe %}')
+        context  = Context.new('unsafe' => (+'unsafe').tap(&:taint))
+        template.render(context)
 
-      assert_equal [Liquid::TaintedError], context.warnings.map(&:class)
-      assert_equal 'snippet', context.warnings.first.template_name
+        assert_equal [Liquid::TaintedError], context.warnings.map(&:class)
+        assert_equal 'snippet', context.warnings.first.template_name
+      end
     end
   end
 

test/integration/template_test.rb

@@ -361,4 +361,12 @@ class TemplateTest < Minitest::Test
     result = t.render('x' => 1, 'y' => 5)
     assert_equal('12345', result)
   end
+
+  unless taint_supported?
+    def test_taint_mode
+      assert_raises(NotImplementedError) do
+        Template.taint_mode = :warn
+      end
+    end
+  end
 end

test/test_helper.rb

@@ -32,6 +32,10 @@ module Minitest
     def fixture(name)
       File.join(File.expand_path(__dir__), "fixtures", name)
     end
+
+    def self.taint_supported?
+      Object.new.taint.tainted?
+    end
   end
 
   module Assertions