From 2b11efc3aebb596d5f84eef98edb589abe092105 Mon Sep 17 00:00:00 2001
From: Dylan Thacker-Smith <dylan.smith@shopify.com>
Date: Tue, 18 Aug 2020 11:25:51 -0400
Subject: [PATCH] Fix performance regression from introduction of
 Template#disable_tags (#1274)

---
 lib/liquid.rb                                 |  3 +-
 lib/liquid/block_body.rb                      | 13 +----
 lib/liquid/context.rb                         | 19 ++++++-
 lib/liquid/profiler/hooks.rb                  | 20 +++-----
 lib/liquid/registers/disabled_tags.rb         | 32 ------------
 lib/liquid/tag.rb                             | 22 ++-------
 lib/liquid/tag/disableable.rb                 | 19 +++++++
 lib/liquid/tag/disabler.rb                    | 21 ++++++++
 lib/liquid/tags/include.rb                    |  2 +
 lib/liquid/template.rb                        | 12 -----
 .../registers/disabled_tags_test.rb           | 27 ----------
 test/integration/tag/disableable_test.rb      | 49 +++++++++++++++++++
 test/integration/template_test.rb             | 44 -----------------
 test/test_helper.rb                           | 15 ++++--
 test/unit/context_unit_test.rb                | 29 +++++++++++
 .../unit/registers/disabled_tags_unit_test.rb | 36 --------------
 16 files changed, 164 insertions(+), 199 deletions(-)
 delete mode 100644 lib/liquid/registers/disabled_tags.rb
 create mode 100644 lib/liquid/tag/disableable.rb
 create mode 100644 lib/liquid/tag/disabler.rb
 delete mode 100644 test/integration/registers/disabled_tags_test.rb
 create mode 100644 test/integration/tag/disableable_test.rb
 delete mode 100644 test/unit/registers/disabled_tags_unit_test.rb

diff --git a/lib/liquid.rb b/lib/liquid.rb
index 84b11e5..e10cdf6 100644
--- a/lib/liquid.rb
+++ b/lib/liquid.rb
@@ -63,6 +63,8 @@ require 'liquid/expression'
 require 'liquid/context'
 require 'liquid/parser_switching'
 require 'liquid/tag'
+require 'liquid/tag/disabler'
+require 'liquid/tag/disableable'
 require 'liquid/block'
 require 'liquid/block_body'
 require 'liquid/document'
@@ -86,4 +88,3 @@ require 'liquid/template_factory'
 # Load all the tags of the standard library
 #
 Dir["#{__dir__}/liquid/tags/*.rb"].each { |f| require f }
-Dir["#{__dir__}/liquid/registers/*.rb"].each { |f| require f }
diff --git a/lib/liquid/block_body.rb b/lib/liquid/block_body.rb
index 467bbdd..67ddf36 100644
--- a/lib/liquid/block_body.rb
+++ b/lib/liquid/block_body.rb
@@ -171,13 +171,7 @@ module Liquid
     private
 
     def render_node(context, output, node)
-      if node.disabled?(context)
-        output << node.disabled_error_message
-        return
-      end
-      disable_tags(context, node.disabled_tags) do
-        node.render_to_output_buffer(context, output)
-      end
+      node.render_to_output_buffer(context, output)
     rescue UndefinedVariable, UndefinedDropMethod, UndefinedFilter => e
       context.handle_error(e, node.line_number)
     rescue ::StandardError => e
@@ -185,11 +179,6 @@ module Liquid
       output << context.handle_error(e, line_number)
     end
 
-    def disable_tags(context, tags, &block)
-      return yield if tags.empty?
-      context.registers[:disabled_tags].disable(tags, &block)
-    end
-
     def raise_if_resource_limits_reached(context, length)
       context.resource_limits.render_length += length
       return unless context.resource_limits.reached?
diff --git a/lib/liquid/context.rb b/lib/liquid/context.rb
index 0737f74..f91b5ff 100644
--- a/lib/liquid/context.rb
+++ b/lib/liquid/context.rb
@@ -44,6 +44,7 @@ module Liquid
       @interrupts    = []
       @filters       = []
       @global_filter = nil
+      @disabled_tags = {}
     end
     # rubocop:enable Metrics/ParameterLists
 
@@ -144,6 +145,7 @@ module Liquid
         subcontext.strainer = nil
         subcontext.errors   = errors
         subcontext.warnings = warnings
+        subcontext.disabled_tags = @disabled_tags
       end
     end
 
@@ -208,9 +210,24 @@ module Liquid
       end
     end
 
+    def with_disabled_tags(tag_names)
+      tag_names.each do |name|
+        @disabled_tags[name] = @disabled_tags.fetch(name, 0) + 1
+      end
+      yield
+    ensure
+      tag_names.each do |name|
+        @disabled_tags[name] -= 1
+      end
+    end
+
+    def tag_disabled?(tag_name)
+      @disabled_tags.fetch(tag_name, 0) > 0
+    end
+
     protected
 
-    attr_writer :base_scope_depth, :warnings, :errors, :strainer, :filters
+    attr_writer :base_scope_depth, :warnings, :errors, :strainer, :filters, :disabled_tags
 
     private
 
diff --git a/lib/liquid/profiler/hooks.rb b/lib/liquid/profiler/hooks.rb
index e708653..eda3c2a 100644
--- a/lib/liquid/profiler/hooks.rb
+++ b/lib/liquid/profiler/hooks.rb
@@ -1,25 +1,21 @@
 # frozen_string_literal: true
 
 module Liquid
-  class BlockBody
-    def render_node_with_profiling(context, output, node)
+  module BlockBodyProfilingHook
+    def render_node(context, output, node)
       Profiler.profile_node_render(node) do
-        render_node_without_profiling(context, output, node)
+        super
       end
     end
-
-    alias_method :render_node_without_profiling, :render_node
-    alias_method :render_node, :render_node_with_profiling
   end
+  BlockBody.prepend(BlockBodyProfilingHook)
 
-  class Include < Tag
-    def render_to_output_buffer_with_profiling(context, output)
+  module IncludeProfilingHook
+    def render_to_output_buffer(context, output)
       Profiler.profile_children(context.evaluate(@template_name_expr).to_s) do
-        render_to_output_buffer_without_profiling(context, output)
+        super
       end
     end
-
-    alias_method :render_to_output_buffer_without_profiling, :render_to_output_buffer
-    alias_method :render_to_output_buffer, :render_to_output_buffer_with_profiling
   end
+  Include.prepend(IncludeProfilingHook)
 end
diff --git a/lib/liquid/registers/disabled_tags.rb b/lib/liquid/registers/disabled_tags.rb
deleted file mode 100644
index 4499099..0000000
--- a/lib/liquid/registers/disabled_tags.rb
+++ /dev/null
@@ -1,32 +0,0 @@
-# frozen_string_literal: true
-module Liquid
-  class DisabledTags < Register
-    def initialize
-      @disabled_tags = {}
-    end
-
-    def disabled?(tag)
-      @disabled_tags.key?(tag) && @disabled_tags[tag] > 0
-    end
-
-    def disable(tags)
-      tags.each(&method(:increment))
-      yield
-    ensure
-      tags.each(&method(:decrement))
-    end
-
-    private
-
-    def increment(tag)
-      @disabled_tags[tag] ||= 0
-      @disabled_tags[tag]  += 1
-    end
-
-    def decrement(tag)
-      @disabled_tags[tag] -= 1
-    end
-  end
-
-  Template.add_register(:disabled_tags, DisabledTags.new)
-end
diff --git a/lib/liquid/tag.rb b/lib/liquid/tag.rb
index 937c802..bd77335 100644
--- a/lib/liquid/tag.rb
+++ b/lib/liquid/tag.rb
@@ -13,15 +13,13 @@ module Liquid
         tag
       end
 
-      def disable_tags(*tags)
-        disabled_tags.push(*tags)
+      def disable_tags(*tag_names)
+        @disabled_tags ||= []
+        @disabled_tags.concat(tag_names)
+        prepend(Disabler)
       end
 
       private :new
-
-      def disabled_tags
-        @disabled_tags ||= []
-      end
     end
 
     def initialize(tag_name, markup, parse_context)
@@ -46,14 +44,6 @@ module Liquid
       ''
     end
 
-    def disabled?(context)
-      context.registers[:disabled_tags].disabled?(tag_name)
-    end
-
-    def disabled_error_message
-      "#{tag_name} #{options[:locale].t('errors.disabled.tag')}"
-    end
-
     # For backwards compatibility with custom tags. In a future release, the semantics
     # of the `render_to_output_buffer` method will become the default and the `render`
     # method will be removed.
@@ -65,9 +55,5 @@ module Liquid
     def blank?
       false
     end
-
-    def disabled_tags
-      self.class.disabled_tags
-    end
   end
 end
diff --git a/lib/liquid/tag/disableable.rb b/lib/liquid/tag/disableable.rb
new file mode 100644
index 0000000..39d1e11
--- /dev/null
+++ b/lib/liquid/tag/disableable.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+module Liquid
+  class Tag
+    module Disableable
+      def render_to_output_buffer(context, output)
+        if context.tag_disabled?(tag_name)
+          output << disabled_error_message
+          return
+        end
+        super
+      end
+
+      def disabled_error_message
+        "#{tag_name} #{parse_context[:locale].t('errors.disabled.tag')}"
+      end
+    end
+  end
+end
diff --git a/lib/liquid/tag/disabler.rb b/lib/liquid/tag/disabler.rb
new file mode 100644
index 0000000..210a177
--- /dev/null
+++ b/lib/liquid/tag/disabler.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Liquid
+  class Tag
+    module Disabler
+      module ClassMethods
+        attr_reader :disabled_tags
+      end
+
+      def self.prepended(base)
+        base.extend(ClassMethods)
+      end
+
+      def render_to_output_buffer(context, output)
+        context.with_disabled_tags(self.class.disabled_tags) do
+          super
+        end
+      end
+    end
+  end
+end
diff --git a/lib/liquid/tags/include.rb b/lib/liquid/tags/include.rb
index 5b7bcc5..f697e51 100644
--- a/lib/liquid/tags/include.rb
+++ b/lib/liquid/tags/include.rb
@@ -16,6 +16,8 @@ module Liquid
   #   {% include 'product' for products %}
   #
   class Include < Tag
+    prepend Tag::Disableable
+
     SYNTAX = /(#{QuotedFragment}+)(\s+(?:with|for)\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
     Syntax = SYNTAX
 
diff --git a/lib/liquid/template.rb b/lib/liquid/template.rb
index 189fcc0..bad8789 100644
--- a/lib/liquid/template.rb
+++ b/lib/liquid/template.rb
@@ -80,14 +80,6 @@ module Liquid
         tags[name.to_s] = klass
       end
 
-      attr_accessor :registers
-      Template.registers = {}
-      private :registers=
-
-      def add_register(name, klass)
-        registers[name.to_sym] = klass
-      end
-
       # Pass a module with filter methods which should be available
       # to all liquid views. Good for registering the standard library
       def register_filter(mod)
@@ -194,10 +186,6 @@ module Liquid
         context.add_filters(args.pop)
       end
 
-      Template.registers.each do |key, register|
-        context_register[key] = register unless context_register.key?(key)
-      end
-
       # Retrying a render resets resource usage
       context.resource_limits.reset
 
diff --git a/test/integration/registers/disabled_tags_test.rb b/test/integration/registers/disabled_tags_test.rb
deleted file mode 100644
index 1fb2458..0000000
--- a/test/integration/registers/disabled_tags_test.rb
+++ /dev/null
@@ -1,27 +0,0 @@
-# frozen_string_literal: true
-
-require 'test_helper'
-
-class DisabledTagsTest < Minitest::Test
-  include Liquid
-
-  class DisableRaw < Block
-    disable_tags "raw"
-  end
-
-  class DisableRawEcho < Block
-    disable_tags "raw", "echo"
-  end
-
-  def test_disables_raw
-    with_custom_tag('disable', DisableRaw) do
-      assert_template_result 'raw usage is not allowed in this contextfoo', '{% disable %}{% raw %}Foobar{% endraw %}{% echo "foo" %}{% enddisable %}'
-    end
-  end
-
-  def test_disables_echo_and_raw
-    with_custom_tag('disable', DisableRawEcho) do
-      assert_template_result 'raw usage is not allowed in this contextecho usage is not allowed in this context', '{% disable %}{% raw %}Foobar{% endraw %}{% echo "foo" %}{% enddisable %}'
-    end
-  end
-end
diff --git a/test/integration/tag/disableable_test.rb b/test/integration/tag/disableable_test.rb
new file mode 100644
index 0000000..4bd57c3
--- /dev/null
+++ b/test/integration/tag/disableable_test.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class TagDisableableTest < Minitest::Test
+  include Liquid
+
+  class DisableRaw < Block
+    disable_tags "raw"
+  end
+
+  class DisableRawEcho < Block
+    disable_tags "raw", "echo"
+  end
+
+  class DisableableRaw < Liquid::Raw
+    prepend Liquid::Tag::Disableable
+  end
+
+  class DisableableEcho < Liquid::Echo
+    prepend Liquid::Tag::Disableable
+  end
+
+  def test_disables_raw
+    with_disableable_tags do
+      with_custom_tag('disable', DisableRaw) do
+        assert_template_result 'raw usage is not allowed in this contextfoo', '{% disable %}{% raw %}Foobar{% endraw %}{% echo "foo" %}{% enddisable %}'
+      end
+    end
+  end
+
+  def test_disables_echo_and_raw
+    with_disableable_tags do
+      with_custom_tag('disable', DisableRawEcho) do
+        assert_template_result 'raw usage is not allowed in this contextecho usage is not allowed in this context', '{% disable %}{% raw %}Foobar{% endraw %}{% echo "foo" %}{% enddisable %}'
+      end
+    end
+  end
+
+  private
+
+  def with_disableable_tags
+    with_custom_tag('raw', DisableableRaw) do
+      with_custom_tag('echo', DisableableEcho) do
+        yield
+      end
+    end
+  end
+end
diff --git a/test/integration/template_test.rb b/test/integration/template_test.rb
index 57d6e4f..014f951 100644
--- a/test/integration/template_test.rb
+++ b/test/integration/template_test.rb
@@ -361,48 +361,4 @@ class TemplateTest < Minitest::Test
     result = t.render('x' => 1, 'y' => 5)
     assert_equal('12345', result)
   end
-
-  def test_render_uses_correct_disabled_tags_instance
-    Liquid::Template.file_system = StubFileSystem.new(
-      'foo' => 'bar',
-      'test_include' => '{% include "foo" %}'
-    )
-
-    disabled_tags = DisabledTags.new
-    context = Context.build(registers: { disabled_tags: disabled_tags })
-
-    source = "{% render 'test_include' %}"
-    parse_context = Liquid::ParseContext.new(line_numbers: true, error_mode: :strict)
-    document = Document.parse(Liquid::Tokenizer.new(source, true), parse_context)
-
-    assert_equal("include usage is not allowed in this context", document.render(context))
-  end
-
-  def test_render_sets_context_static_register_when_register_key_does_exist
-    disabled_tags_for_test = DisabledTags.new
-    Template.add_register(:disabled_tags, disabled_tags_for_test)
-
-    t = Template.parse("{% if true %} Test Template {% endif %}")
-
-    context = Context.new
-    refute(context.registers.key?(:disabled_tags))
-
-    t.render(context)
-
-    assert(context.registers.key?(:disabled_tags))
-    assert_equal(disabled_tags_for_test, context.registers[:disabled_tags])
-  end
-
-  def test_render_does_not_override_context_static_register_when_register_key_exists
-    context = Context.new
-    context.registers[:random_register] = nil
-    Template.add_register(:random_register, {})
-
-    t = Template.parse("{% if true %} Test Template {% endif %}")
-
-    t.render(context)
-
-    assert_nil(context.registers[:random_register])
-    assert(context.registers.key?(:random_register))
-  end
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index f3d5d24..5afd10f 100755
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -98,10 +98,17 @@ module Minitest
     end
 
     def with_custom_tag(tag_name, tag_class)
-      Liquid::Template.register_tag(tag_name, tag_class)
-      yield
-    ensure
-      Liquid::Template.tags.delete(tag_name)
+      old_tag = Liquid::Template.tags[tag_name]
+      begin
+        Liquid::Template.register_tag(tag_name, tag_class)
+        yield
+      ensure
+        if old_tag
+          Liquid::Template.tags[tag_name] = old_tag
+        else
+          Liquid::Template.tags.delete(tag_name)
+        end
+      end
     end
   end
 end
diff --git a/test/unit/context_unit_test.rb b/test/unit/context_unit_test.rb
index c57bbca..cec5608 100644
--- a/test/unit/context_unit_test.rb
+++ b/test/unit/context_unit_test.rb
@@ -563,6 +563,35 @@ class ContextUnitTest < Minitest::Test
     assert_equal('my filter result', template.render(subcontext))
   end
 
+  def test_disables_tag_specified
+    context = Context.new
+    context.with_disabled_tags(%w(foo bar)) do
+      assert_equal true, context.tag_disabled?("foo")
+      assert_equal true, context.tag_disabled?("bar")
+      assert_equal false, context.tag_disabled?("unknown")
+    end
+  end
+
+  def test_disables_nested_tags
+    context = Context.new
+    context.with_disabled_tags(["foo"]) do
+      context.with_disabled_tags(["foo"]) do
+        assert_equal true, context.tag_disabled?("foo")
+        assert_equal false, context.tag_disabled?("bar")
+      end
+      context.with_disabled_tags(["bar"]) do
+        assert_equal true, context.tag_disabled?("foo")
+        assert_equal true, context.tag_disabled?("bar")
+        context.with_disabled_tags(["foo"]) do
+          assert_equal true, context.tag_disabled?("foo")
+          assert_equal true, context.tag_disabled?("bar")
+        end
+      end
+      assert_equal true, context.tag_disabled?("foo")
+      assert_equal false, context.tag_disabled?("bar")
+    end
+  end
+
   private
 
   def assert_no_object_allocations
diff --git a/test/unit/registers/disabled_tags_unit_test.rb b/test/unit/registers/disabled_tags_unit_test.rb
deleted file mode 100644
index 90ac016..0000000
--- a/test/unit/registers/disabled_tags_unit_test.rb
+++ /dev/null
@@ -1,36 +0,0 @@
-# frozen_string_literal: true
-
-require 'test_helper'
-
-class DisabledTagsUnitTest < Minitest::Test
-  include Liquid
-
-  def test_disables_tag_specified
-    register = DisabledTags.new
-    register.disable(%w(foo bar)) do
-      assert_equal true, register.disabled?("foo")
-      assert_equal true, register.disabled?("bar")
-      assert_equal false, register.disabled?("unknown")
-    end
-  end
-
-  def test_disables_nested_tags
-    register = DisabledTags.new
-    register.disable(["foo"]) do
-      register.disable(["foo"]) do
-        assert_equal true, register.disabled?("foo")
-        assert_equal false, register.disabled?("bar")
-      end
-      register.disable(["bar"]) do
-        assert_equal true, register.disabled?("foo")
-        assert_equal true, register.disabled?("bar")
-        register.disable(["foo"]) do
-          assert_equal true, register.disabled?("foo")
-          assert_equal true, register.disabled?("bar")
-        end
-      end
-      assert_equal true, register.disabled?("foo")
-      assert_equal false, register.disabled?("bar")
-    end
-  end
-end