Fix stack level too deep error

.github/probots.yml

@@ -1,2 +0,0 @@
-enabled:
-  - cla

.gitignore

@@ -7,4 +7,3 @@ pkg
 .ruby-version
 Gemfile.lock
 .bundle
-.byebug_history

.rubocop.yml

@@ -1,6 +1,4 @@
-inherit_from:
-  - .rubocop_todo.yml
-  - ./.rubocop_todo.yml
+inherit_from: ./.rubocop_todo.yml
 
 AllCops:
   Exclude:
@@ -9,6 +7,8 @@ AllCops:
 
 Metrics/BlockNesting:
   Max: 3
+  Exclude:
+    - 'lib/liquid/block_body.rb'
 
 Metrics/ModuleLength:
   Enabled: false
@@ -31,8 +31,8 @@ Lint/ParenthesesAsGroupedExpression:
 Lint/UnusedBlockArgument:
   Enabled: false
 
-Layout/EndAlignment:
-  EnforcedStyleAlignWith: variable
+Lint/EndAlignment:
+  AlignWith: variable
 
 Lint/UnusedMethodArgument:
   Enabled: false
@@ -61,10 +61,10 @@ Style/BracesAroundHashParameters:
 Style/NumericLiterals:
   Enabled: false
 
-Layout/SpaceInsideArrayLiteralBrackets:
+Style/SpaceInsideBrackets:
   Enabled: false
 
-Layout/SpaceBeforeBlockBraces:
+Style/SpaceBeforeBlockBraces:
   Enabled: false
 
 Style/Documentation:
@@ -73,22 +73,19 @@ Style/Documentation:
 Style/ClassAndModuleChildren:
   Enabled: false
 
-Style/TrailingCommaInArrayLiteral:
+Style/TrailingComma:
   Enabled: false
 
-Style/TrailingCommaInHashLiteral:
-  Enabled: false
-
-Layout/IndentHash:
+Style/IndentHash:
   EnforcedStyle: consistent
 
 Style/FormatString:
   Enabled: false
 
-Layout/AlignParameters:
+Style/AlignParameters:
   EnforcedStyle: with_fixed_indentation
 
-Layout/MultilineOperationIndentation:
+Style/MultilineOperationIndentation:
   EnforcedStyle: indented
 
 Style/IfUnlessModifier:
@@ -97,7 +94,7 @@ Style/IfUnlessModifier:
 Style/RaiseArgs:
   Enabled: false
 
-Style/PreferredHashMethods:
+Style/DeprecatedHashMethods:
   Enabled: false
 
 Style/RegexpLiteral:
@@ -109,10 +106,10 @@ Style/SymbolLiteral:
 Performance/Count:
   Enabled: false
 
-Naming/ConstantName:
+Style/ConstantName:
   Enabled: false
 
-Layout/CaseIndentation:
+Style/CaseIndentation:
   Enabled: false
 
 Style/ClassVars:
@@ -126,7 +123,3 @@ Style/TrivialAccessors:
 
 Style/WordArray:
   Enabled: false
-
-Naming/MethodName:
-  Exclude:
-    - 'example/server/liquid_servlet.rb'

.rubocop_todo.yml

@@ -1,260 +1,72 @@
-# This configuration was generated by
-# `rubocop --auto-gen-config`
-# on 2019-04-22 19:11:24 -0400 using RuboCop version 0.53.0.
+# This configuration was generated by `rubocop --auto-gen-config`
+# on 2015-06-08 18:16:16 +0000 using RuboCop version 0.32.0.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 1
-# Cop supports --auto-correct.
-# Configuration parameters: Include, TreatCommentsAsGroupSeparators.
-# Include: **/*.gemspec
-Gemspec/OrderedDependencies:
-  Exclude:
-    - 'liquid.gemspec'
-
 # Offense count: 5
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: auto_detection, squiggly, active_support, powerpack, unindent
-Layout/IndentHeredoc:
-  Exclude:
-    - 'test/integration/tags/for_tag_test.rb'
-    - 'test/integration/trim_mode_test.rb'
-
-# Offense count: 6
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: symmetrical, new_line, same_line
-Layout/MultilineMethodCallBraceLayout:
-  Exclude:
-    - 'test/integration/error_handling_test.rb'
-    - 'test/unit/strainer_unit_test.rb'
-
-# Offense count: 2
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: runtime_error, standard_error
-Lint/InheritException:
-  Exclude:
-    - 'lib/liquid/interrupts.rb'
-
-# Offense count: 1
-# Configuration parameters: CheckForMethodsWithNoSideEffects.
-Lint/Void:
-  Exclude:
-    - 'lib/liquid/parse_context.rb'
+Lint/NestedMethodDefinition:
+  Enabled: false
 
 # Offense count: 53
 Metrics/AbcSize:
-  Max: 56
+  Max: 58
 
 # Offense count: 12
 Metrics/CyclomaticComplexity:
-  Max: 13
+  Max: 15
 
-# Offense count: 112
+# Offense count: 553
+# Configuration parameters: AllowURI, URISchemes.
+Metrics/LineLength:
+  Max: 294
+
+# Offense count: 77
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
-  Max: 38
+  Max: 46
 
-# Offense count: 8
+# Offense count: 6
 Metrics/PerceivedComplexity:
-  Max: 11
+  Max: 13
 
-# Offense count: 52
-# Configuration parameters: Blacklist.
-# Blacklist: END, (?-mix:EO[A-Z]{1})
-Naming/HeredocDelimiterNaming:
-  Exclude:
-    - 'test/integration/assign_test.rb'
-    - 'test/integration/capture_test.rb'
-    - 'test/integration/trim_mode_test.rb'
-
-# Offense count: 23
-# Configuration parameters: MinNameLength, AllowNamesEndingInNumbers, AllowedNames, ForbiddenNames.
-# AllowedNames: io, id
-Naming/UncommunicativeMethodParamName:
-  Exclude:
-    - 'example/server/example_servlet.rb'
-    - 'lib/liquid/condition.rb'
-    - 'lib/liquid/context.rb'
-    - 'lib/liquid/standardfilters.rb'
-    - 'lib/liquid/tags/if.rb'
-    - 'lib/liquid/utils.rb'
-    - 'lib/liquid/variable.rb'
-    - 'test/integration/filter_test.rb'
-    - 'test/integration/standard_filter_test.rb'
-    - 'test/integration/tags/for_tag_test.rb'
-    - 'test/integration/template_test.rb'
-    - 'test/unit/condition_unit_test.rb'
-
-# Offense count: 12
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: prefer_alias, prefer_alias_method
-Style/Alias:
-  Exclude:
-    - 'lib/liquid/drop.rb'
-    - 'lib/liquid/i18n.rb'
-    - 'lib/liquid/profiler/hooks.rb'
-    - 'lib/liquid/standardfilters.rb'
-    - 'lib/liquid/tag.rb'
-    - 'lib/liquid/tags/include.rb'
-    - 'lib/liquid/variable.rb'
-
-# Offense count: 22
-Style/CommentedKeyword:
+# Offense count: 1
+Style/AccessorMethodName:
   Enabled: false
 
 # Offense count: 1
 # Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle, SingleLineConditionsOnly, IncludeTernaryExpressions.
-# SupportedStyles: assign_to_condition, assign_inside_condition
-Style/ConditionalAssignment:
-  Exclude:
-    - 'lib/liquid/errors.rb'
-
-# Offense count: 1
-Style/DateTime:
-  Exclude:
-    - 'test/unit/context_unit_test.rb'
-
-# Offense count: 2
-# Cop supports --auto-correct.
-Style/EmptyCaseCondition:
-  Exclude:
-    - 'lib/liquid/block_body.rb'
-    - 'lib/liquid/lexer.rb'
-
-# Offense count: 5
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: compact, expanded
-Style/EmptyMethod:
-  Exclude:
-    - 'lib/liquid/tag.rb'
-    - 'lib/liquid/tags/comment.rb'
-    - 'lib/liquid/tags/include.rb'
-    - 'test/integration/tags/include_tag_test.rb'
-    - 'test/unit/context_unit_test.rb'
+Style/ClosingParenthesisIndentation:
+  Enabled: false
 
 # Offense count: 3
-# Cop supports --auto-correct.
-Style/Encoding:
-  Exclude:
-    - 'lib/liquid/version.rb'
-    - 'liquid.gemspec'
-    - 'test/integration/standard_filter_test.rb'
-
-# Offense count: 2
-# Cop supports --auto-correct.
-Style/ExpandPathArguments:
-  Exclude:
-    - 'Rakefile'
-    - 'liquid.gemspec'
-
-# Offense count: 7
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: annotated, template, unannotated
-Style/FormatStringToken:
-  Exclude:
-    - 'test/integration/filter_test.rb'
-    - 'test/integration/hash_ordering_test.rb'
-
-# Offense count: 14
 # Configuration parameters: MinBodyLength.
 Style/GuardClause:
-  Exclude:
-    - 'lib/liquid/condition.rb'
-    - 'lib/liquid/lexer.rb'
-    - 'lib/liquid/strainer.rb'
-    - 'lib/liquid/tags/assign.rb'
-    - 'lib/liquid/tags/capture.rb'
-    - 'lib/liquid/tags/case.rb'
-    - 'lib/liquid/tags/for.rb'
-    - 'lib/liquid/tags/include.rb'
-    - 'lib/liquid/tags/raw.rb'
-    - 'lib/liquid/tags/table_row.rb'
-    - 'lib/liquid/variable.rb'
-    - 'test/unit/tokenizer_unit_test.rb'
-
-# Offense count: 1
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle, MinBodyLength.
-# SupportedStyles: skip_modifier_ifs, always
-Style/Next:
-  Exclude:
-    - 'lib/liquid/tags/for.rb'
+  Enabled: false
 
 # Offense count: 4
-# Cop supports --auto-correct.
-# Configuration parameters: AutoCorrect, EnforcedStyle.
-# SupportedStyles: predicate, comparison
-Style/NumericPredicate:
-  Exclude:
-    - 'spec/**/*'
-    - 'lib/liquid/context.rb'
-    - 'lib/liquid/forloop_drop.rb'
-    - 'lib/liquid/standardfilters.rb'
-    - 'lib/liquid/tablerowloop_drop.rb'
-
-# Offense count: 14
-# Cop supports --auto-correct.
-# Configuration parameters: PreferredDelimiters.
-Style/PercentLiteralDelimiters:
-  Exclude:
-    - 'lib/liquid/tags/if.rb'
-    - 'liquid.gemspec'
-    - 'test/integration/assign_test.rb'
-    - 'test/integration/standard_filter_test.rb'
+# Configuration parameters: EnforcedStyle, SupportedStyles.
+Style/MethodName:
+  Enabled: false
 
 # Offense count: 1
-# Cop supports --auto-correct.
-Style/RedundantSelf:
-  Exclude:
-    - 'lib/liquid/strainer.rb'
+Style/MultilineBlockChain:
+  Enabled: false
 
-# Offense count: 9
+# Offense count: 2
+# Configuration parameters: EnforcedStyle, MinBodyLength, SupportedStyles.
+Style/Next:
+  Enabled: false
+
+# Offense count: 7
 # Cop supports --auto-correct.
 # Configuration parameters: AllowAsExpressionSeparator.
 Style/Semicolon:
-  Exclude:
-    - 'test/integration/error_handling_test.rb'
-    - 'test/integration/template_test.rb'
-    - 'test/unit/context_unit_test.rb'
-
-# Offense count: 7
-# Cop supports --auto-correct.
-# Configuration parameters: MinSize.
-# SupportedStyles: percent, brackets
-Style/SymbolArray:
-  EnforcedStyle: brackets
-
-# Offense count: 2
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle, AllowSafeAssignment.
-# SupportedStyles: require_parentheses, require_no_parentheses, require_parentheses_when_complex
-Style/TernaryParentheses:
-  Exclude:
-    - 'lib/liquid/context.rb'
-    - 'lib/liquid/utils.rb'
-
-# Offense count: 2
-# Cop supports --auto-correct.
-Style/UnneededPercentQ:
-  Exclude:
-    - 'test/integration/error_handling_test.rb'
+  Enabled: false
 
 # Offense count: 1
 # Cop supports --auto-correct.
+# Configuration parameters: MaxLineLength.
 Style/WhileUntilModifier:
-  Exclude:
-    - 'lib/liquid/tags/case.rb'
-
-# Offense count: 648
-# Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
-# URISchemes: http, https
-Metrics/LineLength:
-  Max: 294
+  Enabled: false

.travis.yml

@@ -3,9 +3,7 @@ language: ruby
 rvm:
   - 2.1
   - 2.2
-  - 2.3
-  - 2.4
-  - 2.5
+  - 2.3.3
   - ruby-head
   - jruby-head
 #  - rbx-2
@@ -19,13 +17,13 @@ addons:
 
 matrix:
   allow_failures:
-    - rvm: ruby-head
     - rvm: jruby-head
 
 install:
+  - gem install rainbow -v 2.2.1
   - bundle install
 
-script: bundle exec rake
+script: "bundle exec rake"
 
 notifications:
   disable: true

Gemfile

@@ -1,27 +1,17 @@
 source 'https://rubygems.org'
-git_source(:github) do |repo_name|
-  "https://github.com/#{repo_name}.git"
-end
 
 gemspec
-
+gem 'stackprof', platforms: :mri_21
 
 group :benchmark, :test do
   gem 'benchmark-ips'
-  gem 'memory_profiler'
-
-  install_if -> { RUBY_PLATFORM !~ /mingw|mswin|java/ } do
-    gem 'stackprof'
-  end
 end
 
 group :test do
-  gem 'rubocop', '~> 0.53.0'
-  gem 'awesome_print'
-  gem 'pry'
-  gem 'byebug'
+  gem 'spy', '0.4.1'
+  gem 'rubocop', '0.34.2'
 
   platform :mri do
-    gem 'liquid-c', github: 'Shopify/liquid-c', ref: '9168659de45d6d576fce30c735f857e597fa26f6'
+    gem 'liquid-c', github: 'Shopify/liquid-c', ref: 'bd53db95de3d44d631e7c5a267c3d934e66107dd'
   end
 end

History.md

@@ -1,58 +1,5 @@
 # Liquid Change Log
 
-## 4.0.3 / 2019-03-12
-
-### Fixed
-* Fix break and continue tags inside included templates in loops (#1072) [Justin Li]
-
-## 4.0.2 / 2019-03-08
-
-### Changed
-* Add `where` filter (#1026) [Samuel Doiron]
-* Add `ParseTreeVisitor` to iterate the Liquid AST (#1025) [Stephen Paul Weber]
-* Improve `strip_html` performance (#1032) [printercu]
-
-### Fixed
-* Add error checking for invalid combinations of inputs to sort, sort_natural, where, uniq, map, compact filters (#1059) [Garland Zhang]
-* Validate the character encoding in url_decode (#1070) [Clayton Smith]
-
-## 4.0.1 / 2018-10-09
-
-### Changed
-* Add benchmark group in Gemfile (#855) [Jerry Liu]
-* Allow benchmarks to benchmark render by itself (#851) [Jerry Liu]
-* Avoid calling `line_number` on String node when rescuing a render error. (#860) [Dylan Thacker-Smith]
-* Avoid duck typing to detect whether to call render on a node. [Dylan Thacker-Smith]
-* Clarify spelling of `reversed` on `for` block tag (#843) [Mark Crossfield]
-* Replace recursion with loop to avoid potential stack overflow from malicious input (#891, #892) [Dylan Thacker-Smith]
-* Limit block tag nesting to 100 (#894) [Dylan Thacker-Smith]
-* Replace `assert_equal nil` with `assert_nil` (#895) [Dylan Thacker-Smith]
-* Remove Spy Gem (#896) [Dylan Thacker-Smith]
-* Add `collection_name` and `variable_name` reader to `For` block (#909)
-* Symbols render as strings (#920) [Justin Li]
-* Remove default value from Hash objects (#932) [Maxime Bedard]
-* Remove one level of nesting (#944) [Dylan Thacker-Smith]
-* Update Rubocop version (#952) [Justin Li]
-* Add `at_least` and `at_most` filters (#954, #958) [Nithin Bekal]
-* Add a regression test for a liquid-c trim mode bug (#972) [Dylan Thacker-Smith]
-* Use https rather than git protocol to fetch liquid-c [Dylan Thacker-Smith]
-* Add tests against Ruby 2.4 (#963) and 2.5 (#981)
-* Replace RegExp literals with constants (#988) [Ashwin Maroli]
-* Replace unnecessary `#each_with_index` with `#each` (#992) [Ashwin Maroli]
-* Improve the unexpected end delimiter message for block tags. (#1003) [Dylan Thacker-Smith]
-* Refactor and optimize rendering (#1005) [Christopher Aue]
-* Add installation instruction (#1006) [Ben Gift]
-* Remove Circle CI (#1010)
-* Rename deprecated `BigDecimal.new` to `BigDecimal` (#1024) [Koichi ITO]
-* Rename deprecated Rubocop name (#1027) [Justin Li]
-
-### Fixed
-* Handle `join` filter on non String joiners (#857) [Richard Monette]
-* Fix duplicate inclusion condition logic error of `Liquid::Strainer.add_filter` method (#861)
-* Fix `escape`, `url_encode`, `url_decode` not handling non-string values (#898) [Thierry Joyal]
-* Fix raise when variable is defined but nil when using `strict_variables` [Pascal Betz]
-* Fix `sort` and `sort_natural` to handle arrays with nils (#930) [Eric Chan]
-
 ## 4.0.0 / 2016-12-14 / branch "4-0-stable"
 
 ### Changed

README.md

@@ -42,8 +42,6 @@ Liquid is a template engine which was written with very specific requirements:
 
 ## How to use Liquid
 
-Install Liquid by adding `gem 'liquid'` to your gemfile.
-
 Liquid supports a very simple API based around the Liquid::Template class.
 For standard use you can just pass it the content of a file and call render with a parameters hash.
 

Rakefile

@@ -3,7 +3,7 @@ require 'rake/testtask'
 $LOAD_PATH.unshift File.expand_path("../lib", __FILE__)
 require "liquid/version"
 
-task default: [:test, :rubocop]
+task default: [:rubocop, :test]
 
 desc 'run test suite with default parser'
 Rake::TestTask.new(:base_test) do |t|
@@ -45,17 +45,6 @@ task :test do
   end
 end
 
-desc 'runs the test suite using the superfluid compiler'
-Rake::TestTask.new(:test_superfluid) do |t|
-  t.libs << '.' << 'lib' << 'test'
-  t.test_files = FileList['test/integration/**/*_test.rb']
-  t.verbose = false
-
-  ENV['LIQUID_PARSER_MODE'] = 'strict'
-  ENV['LIQUID-C'] = '1'
-  ENV['SUPERFLUID'] = '1'
-end
-
 task gem: :build
 task :build do
   system "gem build liquid.gemspec"
@@ -82,11 +71,6 @@ namespace :benchmark do
   task :strict do
     ruby "./performance/benchmark.rb strict"
   end
-
-  desc "Run the liquid benchmark with strict parsing"
-  task :superfluid do
-    ruby "./performance/benchmark.rb superfluid"
-  end
 end
 
 namespace :profile do
@@ -101,13 +85,6 @@ namespace :profile do
   end
 end
 
-namespace :memory_profile do
-  desc "Run memory profiler"
-  task :run do
-    ruby "./performance/memory_profile.rb"
-  end
-end
-
 desc "Run example"
 task :example do
   ruby "-w -d -Ilib example/server/server.rb"

circle.yml

@@ -0,0 +1,3 @@
+machine:
+  ruby:
+    version: ruby-2.1

lib/liquid.rb

@@ -45,7 +45,6 @@ module Liquid
 end
 
 require "liquid/version"
-require 'liquid/parse_tree_visitor'
 require 'liquid/lexer'
 require 'liquid/parser'
 require 'liquid/i18n'

lib/liquid/block.rb

@@ -1,7 +1,5 @@
 module Liquid
   class Block < Tag
-    MAX_DEPTH = 100
-
     def initialize(tag_name, markup, options)
       super
       @blank = true
@@ -13,7 +11,6 @@ module Liquid
       end
     end
 
-    # For backwards compatibility
     def render(context)
       @body.render(context)
     end
@@ -27,12 +24,12 @@ module Liquid
     end
 
     def unknown_tag(tag, _params, _tokens)
-      if tag == 'else'.freeze
+      case tag
+      when 'else'.freeze
         raise SyntaxError.new(parse_context.locale.t("errors.syntax.unexpected_else".freeze,
           block_name: block_name))
-      elsif tag.start_with?('end'.freeze)
+      when 'end'.freeze
         raise SyntaxError.new(parse_context.locale.t("errors.syntax.invalid_delimiter".freeze,
-          tag: tag,
           block_name: block_name,
           block_delimiter: block_delimiter))
       else
@@ -51,25 +48,17 @@ module Liquid
     protected
 
     def parse_body(body, tokens)
-      if parse_context.depth >= MAX_DEPTH
-        raise StackLevelError, "Nesting too deep".freeze
-      end
-      parse_context.depth += 1
-      begin
-        body.parse(tokens, parse_context) do |end_tag_name, end_tag_params|
-          @blank &&= body.blank?
+      body.parse(tokens, parse_context) do |end_tag_name, end_tag_params|
+        @blank &&= body.blank?
 
-          return false if end_tag_name == block_delimiter
-          unless end_tag_name
-            raise SyntaxError.new(parse_context.locale.t("errors.syntax.tag_never_closed".freeze, block_name: block_name))
-          end
-
-          # this tag is not registered with the system
-          # pass it to the current block for special handling or error reporting
-          unknown_tag(end_tag_name, end_tag_params, tokens)
+        return false if end_tag_name == block_delimiter
+        unless end_tag_name
+          raise SyntaxError.new(parse_context.locale.t("errors.syntax.tag_never_closed".freeze, block_name: block_name))
         end
-      ensure
-        parse_context.depth -= 1
+
+        # this tag is not registered with the system
+        # pass it to the current block for special handling or error reporting
+        unknown_tag(end_tag_name, end_tag_params, tokens)
       end
 
       true

lib/liquid/block_body.rb

@@ -2,7 +2,6 @@ module Liquid
   class BlockBody
     FullToken = /\A#{TagStart}#{WhitespaceControl}?\s*(\w+)\s*(.*?)#{WhitespaceControl}?#{TagEnd}\z/om
     ContentOfVariable = /\A#{VariableStart}#{WhitespaceControl}?(.*?)#{WhitespaceControl}?#{VariableEnd}\z/om
-    WhitespaceOrNothing = /\A\s*\z/
     TAGSTART = "{%".freeze
     VARSTART = "{{".freeze
 
@@ -16,35 +15,38 @@ module Liquid
     def parse(tokenizer, parse_context)
       parse_context.line_number = tokenizer.line_number
       while token = tokenizer.shift
-        next if token.empty?
-        case
-        when token.start_with?(TAGSTART)
-          whitespace_handler(token, parse_context)
-          unless token =~ FullToken
-            raise_missing_tag_terminator(token, parse_context)
+        unless token.empty?
+          case
+          when token.start_with?(TAGSTART)
+            whitespace_handler(token, parse_context)
+            if token =~ FullToken
+              tag_name = $1
+              markup = $2
+              # fetch the tag from registered blocks
+              if tag = registered_tags[tag_name]
+                new_tag = tag.parse(tag_name, markup, tokenizer, parse_context)
+                @blank &&= new_tag.blank?
+                @nodelist << new_tag
+              else
+                # end parsing if we reach an unknown tag and let the caller decide
+                # determine how to proceed
+                return yield tag_name, markup
+              end
+            else
+              raise_missing_tag_terminator(token, parse_context)
+            end
+          when token.start_with?(VARSTART)
+            whitespace_handler(token, parse_context)
+            @nodelist << create_variable(token, parse_context)
+            @blank = false
+          else
+            if parse_context.trim_whitespace
+              token.lstrip!
+            end
+            parse_context.trim_whitespace = false
+            @nodelist << token
+            @blank &&= !!(token =~ /\A\s*\z/)
           end
-          tag_name = $1
-          markup = $2
-          # fetch the tag from registered blocks
-          unless tag = registered_tags[tag_name]
-            # end parsing if we reach an unknown tag and let the caller decide
-            # determine how to proceed
-            return yield tag_name, markup
-          end
-          new_tag = tag.parse(tag_name, markup, tokenizer, parse_context)
-          @blank &&= new_tag.blank?
-          @nodelist << new_tag
-        when token.start_with?(VARSTART)
-          whitespace_handler(token, parse_context)
-          @nodelist << create_variable(token, parse_context)
-          @blank = false
-        else
-          if parse_context.trim_whitespace
-            token.lstrip!
-          end
-          parse_context.trim_whitespace = false
-          @nodelist << token
-          @blank &&= !!(token =~ WhitespaceOrNothing)
         end
         parse_context.line_number = tokenizer.line_number
       end
@@ -67,51 +69,52 @@ module Liquid
     end
 
     def render(context)
-      render_to_output_buffer(context, '')
-    end
-
-    def render_to_output_buffer(context, output)
+      output = []
       context.resource_limits.render_score += @nodelist.length
 
-      idx = 0
-      while node = @nodelist[idx]
-        previous_output_size = output.bytesize
+      @nodelist.each do |token|
+        # Break out if we have any unhanded interrupts.
+        break if context.interrupt?
 
-        case node
-        when String
-          output << node
-        when Variable
-          render_node(context, output, node)
-        when Block
-          render_node(context, node.blank? ? '' : output, node)
-          break if context.interrupt? # might have happened in a for-block
-        when Continue, Break
+        begin
           # If we get an Interrupt that means the block must stop processing. An
           # Interrupt is any command that stops block execution such as {% break %}
           # or {% continue %}
-          context.push_interrupt(node.interrupt)
-          break
-        else # Other non-Block tags
-          render_node(context, output, node)
-          break if context.interrupt? # might have happened through an include
-        end
-        idx += 1
+          if token.is_a?(Continue) || token.is_a?(Break)
+            context.push_interrupt(token.interrupt)
+            break
+          end
 
-        context.raise_if_resource_limits_reached(output.bytesize - previous_output_size)
+          node_output = render_node(token, context)
+
+          unless token.is_a?(Block) && token.blank?
+            output << node_output
+          end
+        rescue MemoryError => e
+          raise e
+        rescue UndefinedVariable, UndefinedDropMethod, UndefinedFilter => e
+          context.handle_error(e, token.line_number)
+          output << nil
+        rescue ::StandardError => e
+          line_number = token.is_a?(String) ? nil : token.line_number
+          output << context.handle_error(e, line_number)
+        end
       end
 
-      output
+      output.join
     end
 
     private
 
-    def render_node(context, output, node)
-      node.render_to_output_buffer(context, output)
-    rescue UndefinedVariable, UndefinedDropMethod, UndefinedFilter => e
-      context.handle_error(e, node.line_number)
-    rescue ::StandardError => e
-      line_number = node.is_a?(String) ? nil : node.line_number
-      output << context.handle_error(e, line_number)
+    def render_node(node, context)
+      node_output = node.is_a?(String) ? node : node.render(context)
+      node_output = node_output.is_a?(Array) ? node_output.join : node_output.to_s
+
+      context.resource_limits.render_length += node_output.length
+      if context.resource_limits.reached?
+        raise MemoryError.new("Memory limits exceeded".freeze)
+      end
+      node_output
     end
 
     def create_variable(token, parse_context)

lib/liquid/condition.rb

@@ -7,6 +7,7 @@ module Liquid
   #   c.evaluate #=> true
   #
   class Condition #:nodoc:
+    @@depth = 0
     @@operators = {
       '=='.freeze => ->(cond, left, right) {  cond.send(:equal_variables, left, right) },
       '!='.freeze => ->(cond, left, right) { !cond.send(:equal_variables, left, right) },
@@ -29,7 +30,7 @@ module Liquid
       @@operators
     end
 
-    attr_reader :attachment, :child_condition, :child_relation
+    attr_reader :attachment
     attr_accessor :left, :operator, :right
 
     def initialize(left = nil, operator = nil, right = nil)
@@ -41,22 +42,21 @@ module Liquid
     end
 
     def evaluate(context = Context.new)
-      condition = self
-      result = nil
-      loop do
-        result = interpret_condition(condition.left, condition.right, condition.operator, context)
+      result = interpret_condition(left, right, operator, context)
 
-        case condition.child_relation
-        when :or
-          break if result
-        when :and
-          break unless result
-        else
-          break
+      case @child_relation
+      when :or
+        result || @child_condition.evaluate(context)
+      when :and
+        @@depth += 1
+        if @@depth >= 500
+          @@depth = 0
+          raise StackLevelError, "Nesting too deep".freeze
         end
-        condition = condition.child_condition
+        result && @child_condition.evaluate(context)
+      else
+        result
       end
-      result
     end
 
     def or(condition)
@@ -124,15 +124,6 @@ module Liquid
         end
       end
     end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        [
-          @node.left, @node.right,
-          @node.child_condition, @node.attachment
-        ].compact
-      end
-    end
   end
 
   class ElseCondition < Condition

lib/liquid/context.rb

@@ -37,16 +37,6 @@ module Liquid
       @global_filter = nil
     end
 
-    def raise_argument_error(message)
-      raise Liquid::ArgumentError, message
-    end
-
-    def raise_if_resource_limits_reached(length)
-      resource_limits.render_length += length
-      return unless resource_limits.reached?
-      raise MemoryError.new("Memory limits exceeded".freeze)
-    end
-
     def warnings
       @warnings ||= []
     end
@@ -99,7 +89,7 @@ module Liquid
     # Push new local scope on the stack. use <tt>Context#stack</tt> instead
     def push(new_scope = {})
       @scopes.unshift(new_scope)
-      raise StackLevelError, "Nesting too deep".freeze if @scopes.length > Block::MAX_DEPTH
+      raise StackLevelError, "Nesting too deep".freeze if @scopes.length > 100
     end
 
     # Merge a hash of variables in the current local scope
@@ -181,9 +171,7 @@ module Liquid
       if scope.nil?
         @environments.each do |e|
           variable = lookup_and_evaluate(e, key, raise_on_not_found: raise_on_not_found)
-          # When lookup returned a value OR there is no value but the lookup also did not raise
-          # then it is the value we are looking for.
-          if !variable.nil? || @strict_variables && raise_on_not_found
+          unless variable.nil?
             scope = e
             break
           end

lib/liquid/expression.rb

@@ -19,26 +19,22 @@ module Liquid
       'false'.freeze => false,
       'blank'.freeze => MethodLiteral.new(:blank?, '').freeze,
       'empty'.freeze => MethodLiteral.new(:empty?, '').freeze
-    }.freeze
-
-    SINGLE_QUOTED_STRING = /\A'(.*)'\z/m
-    DOUBLE_QUOTED_STRING = /\A"(.*)"\z/m
-    INTEGERS_REGEX       = /\A(-?\d+)\z/
-    FLOATS_REGEX         = /\A(-?\d[\d\.]+)\z/
-    RANGES_REGEX         = /\A\((\S+)\.\.(\S+)\)\z/
+    }
 
     def self.parse(markup)
       if LITERALS.key?(markup)
         LITERALS[markup]
       else
         case markup
-        when SINGLE_QUOTED_STRING, DOUBLE_QUOTED_STRING
+        when /\A'(.*)'\z/m # Single quoted strings
           $1
-        when INTEGERS_REGEX
+        when /\A"(.*)"\z/m # Double quoted strings
+          $1
+        when /\A(-?\d+)\z/ # Integer and floats
           $1.to_i
-        when RANGES_REGEX
+        when /\A\((\S+)\.\.(\S+)\)\z/ # Ranges
           RangeLookup.parse($1, $2)
-        when FLOATS_REGEX
+        when /\A(-?\d[\d\.]+)\z/ # Floats
           $1.to_f
         else
           VariableLookup.parse(markup)

lib/liquid/extensions.rb

@@ -7,12 +7,6 @@ class String # :nodoc:
   end
 end
 
-class Symbol # :nodoc:
-  def to_liquid
-    to_s
-  end
-end
-
 class Array # :nodoc:
   def to_liquid
     self

lib/liquid/i18n.rb

@@ -26,7 +26,7 @@ module Liquid
     def interpolate(name, vars)
       name.gsub(/%\{(\w+)\}/) do
         # raise TranslationError, "Undefined key #{$1} for interpolation in translation #{name}"  unless vars[$1.to_sym]
-        (vars[$1.to_sym]).to_s
+        "#{vars[$1.to_sym]}"
       end
     end
 

lib/liquid/lexer.rb

@@ -12,14 +12,13 @@ module Liquid
       ')'.freeze => :close_round,
       '?'.freeze => :question,
       '-'.freeze => :dash
-    }.freeze
+    }
     IDENTIFIER = /[a-zA-Z_][\w-]*\??/
     SINGLE_STRING_LITERAL = /'[^\']*'/
     DOUBLE_STRING_LITERAL = /"[^\"]*"/
     NUMBER_LITERAL = /-?\d+(\.\d+)?/
     DOTDOT = /\.\./
     COMPARISON_OPERATOR = /==|!=|<>|<=?|>=?|contains(?=\s)/
-    WHITESPACE_OR_NOTHING = /\s*/
 
     def initialize(input)
       @ss = StringScanner.new(input)
@@ -29,7 +28,7 @@ module Liquid
       @output = []
 
       until @ss.eos?
-        @ss.skip(WHITESPACE_OR_NOTHING)
+        @ss.skip(/\s*/)
         break if @ss.eos?
         tok = case
         when t = @ss.scan(COMPARISON_OPERATOR) then [:comparison, t]

lib/liquid/locales/en.yml

@@ -14,7 +14,7 @@
       if: "Syntax Error in tag 'if' - Valid syntax: if [expression]"
       include: "Error in tag 'include' - Valid syntax: include '[template]' (with|for) [object|collection]"
       unknown_tag: "Unknown tag '%{tag}'"
-      invalid_delimiter: "'%{tag}' is not a valid delimiter for %{block_name} tags. use %{block_delimiter}"
+      invalid_delimiter: "'end' is not a valid delimiter for %{block_name} tags. use %{block_delimiter}"
       unexpected_else: "%{block_name} tag does not expect 'else' tag"
       unexpected_outer_tag: "Unexpected outer '%{tag}' tag"
       tag_termination: "Tag '%{token}' was not properly terminated with regexp: %{tag_end}"

lib/liquid/parse_context.rb

@@ -1,13 +1,12 @@
 module Liquid
   class ParseContext
-    attr_accessor :locale, :line_number, :trim_whitespace, :depth
+    attr_accessor :locale, :line_number, :trim_whitespace
     attr_reader :partial, :warnings, :error_mode
 
     def initialize(options = {})
       @template_options = options ? options.dup : {}
       @locale = @template_options[:locale] ||= I18n.new
       @warnings = []
-      self.depth = 0
       self.partial = false
     end
 

lib/liquid/parse_tree_visitor.rb

@@ -1,42 +0,0 @@
-# frozen_string_literal: true
-
-module Liquid
-  class ParseTreeVisitor
-    def self.for(node, callbacks = Hash.new(proc {}))
-      if defined?(node.class::ParseTreeVisitor)
-        node.class::ParseTreeVisitor
-      else
-        self
-      end.new(node, callbacks)
-    end
-
-    def initialize(node, callbacks)
-      @node = node
-      @callbacks = callbacks
-    end
-
-    def add_callback_for(*classes, &block)
-      callback = block
-      callback = ->(node, _) { yield node } if block.arity.abs == 1
-      callback = ->(_, _) { yield } if block.arity.zero?
-      classes.each { |klass| @callbacks[klass] = callback }
-      self
-    end
-
-    def visit(context = nil)
-      children.map do |node|
-        item, new_context = @callbacks[node.class].call(node, context)
-        [
-          item,
-          ParseTreeVisitor.for(node, @callbacks).visit(new_context || context)
-        ]
-      end
-    end
-
-    protected
-
-    def children
-      @node.respond_to?(:nodelist) ? Array(@node.nodelist) : []
-    end
-  end
-end

lib/liquid/parser.rb

@@ -44,14 +44,11 @@ module Liquid
       tok[0] == type
     end
 
-    SINGLE_TOKEN_EXPRESSION_TYPES = [:string, :number].freeze
-    private_constant :SINGLE_TOKEN_EXPRESSION_TYPES
-
     def expression
       token = @tokens[@p]
       if token[0] == :id
         variable_signature
-      elsif SINGLE_TOKEN_EXPRESSION_TYPES.include? token[0]
+      elsif [:string, :number].include? token[0]
         consume
       elsif token.first == :open_round
         consume

lib/liquid/profiler/hooks.rb

@@ -1,8 +1,8 @@
 module Liquid
   class BlockBody
-    def render_node_with_profiling(context, output, node)
+    def render_node_with_profiling(node, context)
       Profiler.profile_node_render(node) do
-        render_node_without_profiling(context, output, node)
+        render_node_without_profiling(node, context)
       end
     end
 
@@ -11,13 +11,13 @@ module Liquid
   end
 
   class Include < Tag
-    def render_to_output_buffer_with_profiling(context, output)
+    def render_with_profiling(context)
       Profiler.profile_children(context.evaluate(@template_name_expr).to_s) do
-        render_to_output_buffer_without_profiling(context, output)
+        render_without_profiling(context)
       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
+    alias_method :render_without_profiling, :render
+    alias_method :render, :render_with_profiling
   end
 end

lib/liquid/range_lookup.rb

@@ -15,8 +15,6 @@ module Liquid
       @end_obj = end_obj
     end
 
-    attr_reader :start_obj, :end_obj
-
     def evaluate(context)
       start_int = to_integer(context.evaluate(@start_obj))
       end_int = to_integer(context.evaluate(@end_obj))

lib/liquid/standardfilters.rb

@@ -9,14 +9,8 @@ module Liquid
       '<'.freeze => '&lt;'.freeze,
       '"'.freeze => '&quot;'.freeze,
       "'".freeze => '&#39;'.freeze
-    }.freeze
+    }
     HTML_ESCAPE_ONCE_REGEXP = /["><']|&(?!([a-zA-Z]+|(#\d+));)/
-    STRIP_HTML_BLOCKS = Regexp.union(
-      /<script.*?<\/script>/m,
-      /<!--.*?-->/m,
-      /<style.*?<\/style>/m
-    )
-    STRIP_HTML_TAGS = /<.*?>/m
 
     # Return the size of an array or of an string
     def size(input)
@@ -39,7 +33,7 @@ module Liquid
     end
 
     def escape(input)
-      CGI.escapeHTML(input.to_s).untaint unless input.nil?
+      CGI.escapeHTML(input).untaint unless input.nil?
     end
     alias_method :h, :escape
 
@@ -48,16 +42,11 @@ module Liquid
     end
 
     def url_encode(input)
-      CGI.escape(input.to_s) unless input.nil?
+      CGI.escape(input) unless input.nil?
     end
 
     def url_decode(input)
-      return if input.nil?
-
-      result = CGI.unescape(input.to_s)
-      raise Liquid::ArgumentError, "invalid byte sequence in #{result.encoding}" unless result.valid_encoding?
-
-      result
+      CGI.unescape(input) unless input.nil?
     end
 
     def slice(input, offset, length = nil)
@@ -79,7 +68,7 @@ module Liquid
       truncate_string_str = truncate_string.to_s
       l = length - truncate_string_str.length
       l = 0 if l < 0
-      input_str.length > length ? input_str[0...l].concat(truncate_string_str) : input_str
+      input_str.length > length ? input_str[0...l] + truncate_string_str : input_str
     end
 
     def truncatewords(input, words = 15, truncate_string = "...".freeze)
@@ -88,7 +77,7 @@ module Liquid
       words = Utils.to_integer(words)
       l = words - 1
       l = 0 if l < 0
-      wordlist.length > l ? wordlist[0..l].join(" ".freeze).concat(truncate_string.to_s) : input
+      wordlist.length > l ? wordlist[0..l].join(" ".freeze) + truncate_string.to_s : input
     end
 
     # Split input string into an array of substrings separated by given pattern.
@@ -114,9 +103,7 @@ module Liquid
 
     def strip_html(input)
       empty = ''.freeze
-      result = input.to_s.gsub(STRIP_HTML_BLOCKS, empty)
-      result.gsub!(STRIP_HTML_TAGS, empty)
-      result
+      input.to_s.gsub(/<script.*?<\/script>/m, empty).gsub(/<!--.*?-->/m, empty).gsub(/<style.*?<\/style>/m, empty).gsub(/<.*?>/m, empty)
     end
 
     # Remove all newlines from the string
@@ -133,18 +120,19 @@ module Liquid
     # provide optional property with which to sort an array of hashes or drops
     def sort(input, property = nil)
       ary = InputIterator.new(input)
-
-      return [] if ary.empty?
-
       if property.nil?
+        ary.sort
+      elsif ary.empty? # The next two cases assume a non-empty array.
+        []
+      elsif ary.first.respond_to?(:[]) && !ary.first[property].nil?
         ary.sort do |a, b|
-          nil_safe_compare(a, b)
-        end
-      elsif ary.all? { |el| el.respond_to?(:[]) }
-        begin
-          ary.sort { |a, b| nil_safe_compare(a[property], b[property]) }
-        rescue TypeError
-          raise_property_error(property)
+          a = a[property]
+          b = b[property]
+          if a && b
+            a <=> b
+          else
+            a ? -1 : 1
+          end
         end
       end
     end
@@ -154,40 +142,12 @@ module Liquid
     def sort_natural(input, property = nil)
       ary = InputIterator.new(input)
 
-      return [] if ary.empty?
-
       if property.nil?
-        ary.sort do |a, b|
-          nil_safe_casecmp(a, b)
-        end
-      elsif ary.all? { |el| el.respond_to?(:[]) }
-        begin
-          ary.sort { |a, b| nil_safe_casecmp(a[property], b[property]) }
-        rescue TypeError
-          raise_property_error(property)
-        end
-      end
-    end
-
-    # Filter the elements of an array to those with a certain property value.
-    # By default the target is any truthy value.
-    def where(input, property, target_value = nil)
-      ary = InputIterator.new(input)
-
-      if ary.empty?
+        ary.sort { |a, b| a.casecmp(b) }
+      elsif ary.empty? # The next two cases assume a non-empty array.
         []
-      elsif ary.first.respond_to?(:[]) && target_value.nil?
-        begin
-          ary.select { |item| item[property] }
-        rescue TypeError
-          raise_property_error(property)
-        end
-      elsif ary.first.respond_to?(:[])
-        begin
-          ary.select { |item| item[property] == target_value }
-        rescue TypeError
-          raise_property_error(property)
-        end
+      elsif ary.first.respond_to?(:[]) && !ary.first[property].nil?
+        ary.sort { |a, b| a[property].casecmp(b[property]) }
       end
     end
 
@@ -201,11 +161,7 @@ module Liquid
       elsif ary.empty? # The next two cases assume a non-empty array.
         []
       elsif ary.first.respond_to?(:[])
-        begin
-          ary.uniq { |a| a[property] }
-        rescue TypeError
-          raise_property_error(property)
-        end
+        ary.uniq{ |a| a[property] }
       end
     end
 
@@ -227,8 +183,6 @@ module Liquid
           r.is_a?(Proc) ? r.call : r
         end
       end
-    rescue TypeError
-      raise_property_error(property)
     end
 
     # Remove nils within an array
@@ -241,11 +195,7 @@ module Liquid
       elsif ary.empty? # The next two cases assume a non-empty array.
         []
       elsif ary.first.respond_to?(:[])
-        begin
-          ary.reject { |a| a[property].nil? }
-        rescue TypeError
-          raise_property_error(property)
-        end
+        ary.reject{ |a| a[property].nil? }
       end
     end
 
@@ -403,22 +353,6 @@ module Liquid
       raise Liquid::FloatDomainError, e.message
     end
 
-    def at_least(input, n)
-      min_value = Utils.to_number(n)
-
-      result = Utils.to_number(input)
-      result = min_value if min_value > result
-      result.is_a?(BigDecimal) ? result.to_f : result
-    end
-
-    def at_most(input, n)
-      max_value = Utils.to_number(n)
-
-      result = Utils.to_number(input)
-      result = max_value if max_value < result
-      result.is_a?(BigDecimal) ? result.to_f : result
-    end
-
     def default(input, default_value = ''.freeze)
       if !input || input.respond_to?(:empty?) && input.empty?
         default_value
@@ -429,31 +363,11 @@ module Liquid
 
     private
 
-    def raise_property_error(property)
-      raise Liquid::ArgumentError.new("cannot select the property '#{property}'")
-    end
-
     def apply_operation(input, operand, operation)
       result = Utils.to_number(input).send(operation, Utils.to_number(operand))
       result.is_a?(BigDecimal) ? result.to_f : result
     end
 
-    def nil_safe_compare(a, b)
-      if !a.nil? && !b.nil?
-        a <=> b
-      else
-        a.nil? ? 1 : -1
-      end
-    end
-
-    def nil_safe_casecmp(a, b)
-      if !a.nil? && !b.nil?
-        a.to_s.casecmp(b.to_s)
-      else
-        a.nil? ? 1 : -1
-      end
-    end
-
     class InputIterator
       include Enumerable
 

lib/liquid/superfluid.rb

@@ -1,632 +0,0 @@
-require 'ap'
-
-require 'pry'
-
-require 'stackprof'
-
-AwesomePrint.defaults = {
-  raw: true
-}
-
-module Liquid
-  Liquid::BlockBody.class_eval do
-    def render_to_output_buffer(context, output)
-
-      ruby = Compiler.compile(@nodelist)
-      
-      if false
-        puts
-        puts "--------------------------- GENERATED RUBY -"
-        line_number = 1
-        puts(ruby.lines.map do |line|
-          "#{line_number}\t#{line}".tap { line_number += 1}
-        end)
-        puts "--------------------------- /GENERATED RUBY -"
-      end
-
-      instructions = RubyVM::InstructionSequence.compile(ruby)
-
-      output_io = StringIO.new
-      instructions.eval.call(output_io, context, Condition)
-
-      output << output_io.string
-    end
-  end
-
-  class SuperfluidError < Exception
-  end
-
-  class Output
-    attr_reader :string, :indent_level
-
-    def initialize(initial_indent)
-      @string = ''.dup
-      @indent_level = initial_indent
-      @indent_str = " " * initial_indent * 2
-    end
-
-    def line(string)
-      @string << @indent_str << string << "\n"
-    end
-
-    def echo(string)
-      output << "liquid_out.write(to_output(#{string}))"
-    end
-
-    def indent(&block)
-      output.indent(&block)
-    end
-
-    def indent
-      @indent_level += 1
-      @indent_str = " " * @indent_level * 2
-      yield
-      @indent_level -= 1
-      @indent_str = " " * @indent_level * 2
-    end
-  end
-
-  class Compiler
-    class << self
-      def compile(template)
-        compiler = new
-        compiler.compile(template)
-        compiler.ruby
-      end
-    end
-
-    def initialize
-      @variables = Set.new
-      @output = Output.new(2)
-      @blank = false
-    end
-
-    def ruby
-      [
-        header,
-        @output.string,
-        trailer
-      ].join("\n")
-    end
-
-
-    def header
-      <<~RUBY
-      module Warning
-        def warn(*)
-        end
-      end
-
-      class ForloopDrop
-        def initialize(name, length, parentloop)
-          @name = name
-          @length = length
-          @parentloop = parentloop
-          @index = 0
-        end
-
-        attr_accessor :parentloop
-
-        def [](value)
-          case value
-          when "length"
-            @length
-          when "name"
-            @name
-          when "index"
-            @index + 1
-          when "index0"
-            @index
-          when "rindex"
-            @length - @index
-          when "rindex0"
-            @length - @index - 1
-          when "first"
-            @index == 0
-          when "last"
-            @index == @length - 1
-          when "parentloop"
-            @parentloop
-          end
-        end
-
-        def to_liquid
-          self
-        end
-
-        def key?(*)
-          true
-        end
-
-        private
-
-        def increment!
-          @index += 1
-        end
-      end
-
-      def slice_collection(collection, from, limit)
-        to = if limit.nil?
-          nil
-        else
-          limit + from
-        end
-
-        if (from != 0 || !to.nil?) && collection.respond_to?(:load_slice)
-          collection.load_slice(from, to)
-        else
-          slice_collection_using_each(collection, from, to)
-        end
-      end
-
-      def slice_collection_using_each(collection, from, to)
-        segments = []
-        index = 0
-
-        if collection.is_a?(String)
-          return collection.empty? ? [] : [collection]
-        end
-        return [] unless collection.respond_to?(:each)
-
-        collection.each do |item|
-          if to && to <= index
-            break
-          end
-
-          if from <= index
-            segments << item
-          end
-
-          index += 1
-        end
-
-        segments
-      end
-
-      def apply_operator(left, operator, right)
-        if left.respond_to?(operator) && right.respond_to?(operator) && !left.is_a?(Hash) && !right.is_a?(Hash)
-          begin
-            left.send(operator, right)
-          rescue ::ArgumentError => e
-            raise @context.raise_argument_error(e.message)
-          end
-        end
-      end
-
-      def contains?(left, right)
-        if left && right && left.respond_to?(:include?)
-          right = right.to_s if left.is_a?(String)
-          left.include?(right)
-        else
-          false
-        end
-      end
-
-      class GlobalVariableLookup
-        def method_missing(method_name, *)
-          nil
-        end
-
-        def to_output(value)
-          output = if value.is_a?(Array)
-            value.join
-          elsif value == nil
-          else
-            value.to_s
-          end
-          @context.apply_global_filter(output)
-        end
-
-        def run(liquid_out, context, condition)
-          @condition = condition
-          @context = context
-          @for_offsets = {}
-          @cycle_values = {}
-          @context.registers[:for_stack] = []
-          @context.registers[:cycle] ||= {}
-          @if_changed_last = nil
-          @prev_output_size = 0
-          #{hoisted_variables}
-      RUBY
-    end
-
-    def trailer
-      <<~RUBY
-          end
-        end
-        GlobalVariableLookup.new.method(:run)
-      RUBY
-    end
-
-    def hoisted_variables
-      @variables.map do |variable|
-        normal_name = unvar(variable)
-        "#{variable} = @context.find_variable(#{normal_name.inspect}, raise_on_not_found: false)"
-      end.join("\n")
-    end
-
-    def compile(node)
-      old_blank = @blank
-      @blank = if node.respond_to?(:blank?)
-        node.blank?
-      elsif !(node.is_a?(String) && node =~ /\A\s*\z/)
-        false
-      else
-        @blank
-      end
-
-      case node
-      when Liquid::Document, Liquid::BlockBody
-        node.nodelist.collect(&method(:compile))
-      when Array
-        node.collect(&method(:compile))
-      when Liquid::Variable
-        compile_variable(node)
-      when Liquid::For
-        compile_for(node)
-      when Liquid::If
-        compile_if(node)
-      when Liquid::Ifchanged
-        compile_if_changed(node)
-      when Liquid::Template
-        compile(node.root)
-      when Liquid::Assign
-        compile_assign(node)
-      when Liquid::Case
-        compile_case(node)
-      when Liquid::Capture
-        compile_capture(node)
-      when String
-        compile_echo_literal(node)
-      when Liquid::Break
-        line "break" if @in_loop
-      when Liquid::Continue
-        line "next" if @in_loop
-      when Liquid::Cycle
-        compile_cycle(node)
-      when Liquid::Raw
-        compile_raw(node)
-      when Liquid::Increment
-        compile_increment(node)
-      when Liquid::Decrement
-        compile_decrement(node)
-      when Liquid::Comment
-      else
-        raise SuperfluidError, "Unknown node type #{node.inspect}"
-      end
-
-      @blank = old_blank
-    end
-
-    def compile_for(node)
-      variable_name = node.variable_name
-
-      collection_name = node.collection_name
-
-      iter_target_expr = case collection_name
-      when Liquid::VariableLookup
-        make_variable_lookup_expr(collection_name)
-      when Range
-        collection_name
-      when Liquid::RangeLookup
-        start_expr = make_variable_expr(collection_name.start_obj)
-        end_expr = make_variable_expr(collection_name.end_obj)
-        line "start = #{start_expr}"
-        line "@context.raise_argument_error('bad value for range') unless start.respond_to?(:to_i)"
-        line "start = #{start_expr}.to_i"
-
-        line "finish = #{end_expr}"
-        line "@context.raise_argument_error('bad value for range') unless finish.respond_to?(:to_i)"
-        line "finish = #{end_expr}.to_i"
-
-        "start..finish"
-      when Liquid::Expression::MethodLiteral
-        '[]'
-      else
-        raise SuperfluidError, "Unknown iteration target: #{collection_name.inspect}"
-      end
-
-      from_expr = if node.from == :continue
-        "@for_offsets['#{node.name}'].to_i"
-      elsif node.from
-        make_variable_expr(node.from)
-      else
-        '0'
-      end
-
-      limit_expr = node.limit ? make_variable_expr(node.limit) : 'nil'
-      line "from = #{from_expr}"
-      line "limit = #{limit_expr}"
-      line "@context.raise_argument_error('invalid integer') unless from.is_a?(Integer)"
-      line "@context.raise_argument_error('invalid integer') unless !limit || limit.is_a?(Integer)"
-
-      line "segment = slice_collection(#{iter_target_expr}, from, limit)"
-      line "segment.reverse!" if node.reversed
-
-      forloop = var('forloop')
-      hoist_var('forloop')
-      line "#{forloop} = ForloopDrop.new('#{node.name}', segment.length, #{forloop})"
-
-      line "if segment.any?"
-      indent do
-        line "segment.each do |#{var(variable_name)}|"
-          indent do
-            line "@context['forloop'] = #{forloop}"
-
-
-            old_in_loop = @in_loop
-            compile(node.for_block)
-            @in_loop = old_in_loop
-
-            line "#{forloop}.send(:increment!)"
-          end
-        line "end"
-      end
-      line "else"
-      indent do
-        compile(node.else_block) if node.else_block
-      end
-      line "end"
-
-      line "@for_offsets['#{node.name}'] = from + segment.length"
-      line "#{forloop} = #{forloop}.parentloop"
-    end
-
-    def compile_if(node)
-      if_condition = node.blocks.first
-      line "if #{make_condition_expr(if_condition)}"
-      indent { if_condition.attachment.nodelist.each(&method(:compile)) }
-
-      node.blocks.drop(1).each do |condition|
-        if condition.left != nil
-          line "elsif #{make_condition_expr(condition)}"
-        else
-          line "else"
-        end
-        indent { condition.attachment.nodelist.each(&method(:compile)) }
-      end
-
-      line "end"
-    end
-
-    def compile_if_changed(node)
-      line "if_changed = lambda do |; liquid_out|"
-      indent do
-        line "liquid_out = StringIO.new"
-        node.nodelist.each(&method(:compile))
-        line "liquid_out.string"
-      end
-      line "end.call"
-
-      line "if if_changed != @if_changed_last"
-      indent { echo "if_changed" }
-      line "end"
-
-      line "@if_changed_last = if_changed"
-    end
-
-    def compile_capture(node)
-      line "#{var(node.to)} = lambda do |; liquid_out|"
-      hoist_var(node.to)
-      indent do
-        line "liquid_out = StringIO.new"
-        node.nodelist.each(&method(:compile))
-        line "liquid_out.string"
-      end
-      line "end.call"
-    end
-
-    def make_condition_expr(node)
-      condition = make_sub_condition_expr(node)
-      if node.child_condition
-        "(#{condition} #{node.child_relation} #{make_condition_expr(node.child_condition)})"
-      else
-        condition
-      end
-    end
-
-    def make_sub_condition_expr(node)
-      return make_variable_expr(node.left) unless node.operator
-
-      operator = node.operator
-      operator = "!=" if operator == "<>"
-
-      if operator == "=="
-        if node.left.is_a?(Liquid::Expression::MethodLiteral) &&
-          node.right.is_a?(Liquid::Expression::MethodLiteral)
-          return "false"
-        elsif node.right.is_a?(Liquid::Expression::MethodLiteral)
-          target = make_variable_expr(node.left)
-          message = node.right.method_name.inspect
-          return "#{target}.respond_to?(#{message}) ? #{target}.send(#{message}) : nil"
-        elsif node.left.is_a?(Liquid::Expression::MethodLiteral)
-          target = make_variable_expr(node.right)
-          message = node.left.method_name.inspect
-          return "#{target}.respond_to?(#{message}) ? #{target}.send(#{message}) : nil"
-        end
-      end
-
-      left = make_variable_expr(node.left)
-      right = make_variable_expr(node.right)
-
-      case operator
-      when "contains"
-        "contains?(#{left}, #{right})"
-      else
-        "apply_operator(#{left}, #{operator.inspect}, #{right})"
-      end
-    end
-
-    def compile_case(node)
-      line 'if false' # HACK
-      else_nodes, if_nodes = node.blocks.partition { |n| n.is_a?(Liquid::ElseCondition) }
-      raise SuperfluidError, 'Too many else nodes' if else_nodes.count > 1
-      else_node = else_nodes.first
-
-      if_nodes.each do |condition|
-        left = make_variable_expr(condition.left)
-        right = make_variable_expr(condition.right)
-        line "elsif #{left} #{condition.operator} #{right}"
-        indent { condition.attachment.nodelist.each(&method(:compile)) }
-      end
-
-      if else_node
-        line "else"
-        indent { else_node.attachment.nodelist.each(&method(:compile)) }
-      end
-
-      line "end"
-    end
-
-    def compile_cycle(node)
-      key = node.name
-      key = key.name if key.is_a?(Liquid::VariableLookup)
-
-      line "key = #{key.inspect}"
-      line "iteration = context.registers[:cycle][key].to_i"
-      line "@cycle_values[key] ||= #{node.variables}"
-
-      line "val = @cycle_values[key][iteration]"
-      echo 'val'
-      line "context.registers[:cycle][key] = (iteration + 1) % #{node.variables.size}"
-    end
-
-    def compile_raw(node)
-      echo "#{node.body.inspect}"
-    end
-
-    def compile_increment(node)
-      line "value = context.environments.first[#{node.variable.inspect}] ||= 0"
-      line "@context.environments.first[#{node.variable.inspect}] = value + 1"
-      echo "value"
-    end
-
-    def compile_decrement(node)
-      line "value = context.environments.first[#{node.variable.inspect}] ||= 0"
-      line "value -= 1"
-      line "@context.environments.first[#{node.variable.inspect}] = value"
-      echo "value"
-    end
-
-    def compile_echo_literal(node)
-      echo node.inspect
-    end
-
-    def compile_variable(variable)
-      echo make_variable_expr(variable)
-    end
-
-    def compile_assign(node)
-      from_expr = case node.from
-      when Liquid::Variable
-        make_variable_expr(node.from)
-      else
-        raise SuperfluidError, "Unknown assignment `from`: #{node.from.inspect}"
-      end
-
-      line "#{var(node.to)} = #{from_expr}"
-      hoist_var(node.to)
-    end
-
-    def make_variable_expr(variable)
-      case variable
-      when Liquid::Variable
-        base_expression = case variable.name
-        when TrueClass, FalseClass, Numeric, String
-          variable.name.inspect
-        when Liquid::VariableLookup
-          make_variable_lookup_expr(variable.name)
-        when NilClass, Liquid::Expression::MethodLiteral
-          'nil'
-        else
-          raise SuperfluidError, "Invalid variable name: #{variable.name.inspect}"
-          derp "Bad var name", variable.name
-        end
-        variable.filters.inject(base_expression) do |inner, (filter_name, positional_args, keyword_args)|
-          filter_args = positional_args.map(&method(:make_variable_expr))
-
-          if keyword_args
-             filter_args << "{ " + keyword_args
-              .transform_values(&method(:make_variable_expr))
-              .collect { |(key, value)| "#{key.inspect} => #{value}" }
-              .join(", ") + " }"
-          end
-
-          "context.strainer.invoke(#{filter_name.inspect}, #{inner}, *[#{filter_args.join(", ")}])"
-        end
-      when Liquid::VariableLookup
-        make_variable_lookup_expr(variable)
-      when TrueClass, FalseClass, Numeric, String
-        variable.inspect
-      when NilClass
-        'nil'
-      else
-        raise SuperfluidError, "Unknown expression type: #{variable.inspect}"
-      end
-    end
-
-    def make_variable_lookup_expr(variable_lookup)
-      base_expr = var(variable_lookup.name)
-      hoist_var(variable_lookup.name)
-      return base_expr if variable_lookup.lookups.empty?
-      
-      expr = Output.new(output.indent_level)
-      expr.line "(begin"
-      expr.indent do
-        expr.line "inner = #{base_expr}"
-        variable_lookup.lookups.each_with_index do |lookup, i|
-          lookup_expr = lookup.inspect
-          expr.line "inner = if inner.respond_to?(:[]) && ((inner.respond_to?(:key?) && inner.key?(#{lookup_expr})) || (inner.respond_to?(:fetch) && #{lookup_expr}.is_a?(Integer)))"
-          expr.indent do
-            expr.line "inner[#{lookup_expr}].to_liquid"
-          end
-          if variable_lookup.command_flags & (1 << i) != 0
-            expr.line "elsif inner.respond_to?(#{lookup.inspect})"
-            expr.indent do
-              expr.line "inner.#{lookup}.to_liquid"
-            end
-          end
-          expr.line "end"
-        end
-      end
-      expr.line "end)"
-      expr.string.strip
-    end
-
-    private
-
-    def line(string)
-      output.line(string)
-    end
-
-    def echo(string)
-      unless @blank
-        line "liquid_out.write(to_output(#{string}))"
-      end
-    end
-
-    def indent(&block)
-      output.indent(&block)
-    end
-
-    def var(name)
-      name = name
-        .gsub('_', '__')
-        .gsub('-', '_')
-      "__liquid_#{name}"
-    end
-
-    def unvar(name)
-      name
-        .delete_prefix('__liquid_')
-        .gsub(/([^_])_([^_])/) { "#$1-#$2" }
-        .gsub('__', '_')
-    end
-
-    def hoist_var(name)
-      @variables << var(name)
-    end
-
-    attr_reader :output
-  end
-end

lib/liquid/tag.rb

@@ -36,14 +36,6 @@ module Liquid
       ''.freeze
     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.
-    def render_to_output_buffer(context, output)
-      output << render(context)
-      output
-    end
-
     def blank?
       false
     end

lib/liquid/tags/assign.rb

@@ -10,8 +10,6 @@ module Liquid
   class Assign < Tag
     Syntax = /(#{VariableSignature}+)\s*=\s*(.*)\s*/om
 
-    attr_reader :to, :from
-
     def initialize(tag_name, markup, options)
       super
       if markup =~ Syntax
@@ -22,11 +20,11 @@ module Liquid
       end
     end
 
-    def render_to_output_buffer(context, output)
+    def render(context)
       val = @from.render(context)
       context.scopes.last[@to] = val
       context.resource_limits.assign_score += assign_score_of(val)
-      output
+      ''.freeze
     end
 
     def blank?
@@ -37,7 +35,7 @@ module Liquid
 
     def assign_score_of(val)
       if val.instance_of?(String)
-        val.bytesize
+        val.length
       elsif val.instance_of?(Array) || val.instance_of?(Hash)
         sum = 1
         # Uses #each to avoid extra allocations.
@@ -47,12 +45,6 @@ module Liquid
         1
       end
     end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        [@node.from]
-      end
-    end
   end
 
   Template.register_tag('assign'.freeze, Assign)

lib/liquid/tags/capture.rb

@@ -13,8 +13,6 @@ module Liquid
   class Capture < Block
     Syntax = /(#{VariableSignature}+)/o
 
-    attr_reader :to
-
     def initialize(tag_name, markup, options)
       super
       if markup =~ Syntax
@@ -24,18 +22,16 @@ module Liquid
       end
     end
 
-    def render_to_output_buffer(context, output)
-      previous_output_size = output.bytesize
-      super
+    def render(context)
+      output = super
       context.scopes.last[@to] = output
-      context.resource_limits.assign_score += (output.bytesize - previous_output_size)
-      output
+      context.resource_limits.assign_score += output.length
+      ''.freeze
     end
 
     def blank?
       true
     end
-
   end
 
   Template.register_tag('capture'.freeze, Capture)

lib/liquid/tags/case.rb

@@ -3,8 +3,6 @@ module Liquid
     Syntax     = /(#{QuotedFragment})/o
     WhenSyntax = /(#{QuotedFragment})(?:(?:\s+or\s+|\s*\,\s*)(#{QuotedFragment}.*))?/om
 
-    attr_reader :blocks, :left
-
     def initialize(tag_name, markup, options)
       super
       @blocks = []
@@ -38,21 +36,21 @@ module Liquid
       end
     end
 
-    def render_to_output_buffer(context, output)
+    def render(context)
       context.stack do
         execute_else_block = true
 
+        output = ''
         @blocks.each do |block|
           if block.else?
-            block.attachment.render_to_output_buffer(context, output) if execute_else_block
+            return block.attachment.render(context) if execute_else_block
           elsif block.evaluate(context)
             execute_else_block = false
-            block.attachment.render_to_output_buffer(context, output)
+            output << block.attachment.render(context)
           end
         end
+        output
       end
-
-      output
     end
 
     private
@@ -82,12 +80,6 @@ module Liquid
       block.attach(BlockBody.new)
       @blocks << block
     end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        [@node.left] + @node.blocks
-      end
-    end
   end
 
   Template.register_tag('case'.freeze, Case)

lib/liquid/tags/comment.rb

@@ -1,7 +1,7 @@
 module Liquid
   class Comment < Block
-    def render_to_output_buffer(_context, output)
-      output
+    def render(_context)
+      ''.freeze
     end
 
     def unknown_tag(_tag, _markup, _tokens)

lib/liquid/tags/cycle.rb

@@ -15,8 +15,6 @@ module Liquid
     SimpleSyntax = /\A#{QuotedFragment}+/o
     NamedSyntax  = /\A(#{QuotedFragment})\s*\:\s*(.*)/om
 
-    attr_reader :variables, :name
-
     def initialize(tag_name, markup, options)
       super
       case markup
@@ -31,29 +29,18 @@ module Liquid
       end
     end
 
-    def render_to_output_buffer(context, output)
-      context.registers[:cycle] ||= {}
+    def render(context)
+      context.registers[:cycle] ||= Hash.new(0)
 
       context.stack do
         key = context.evaluate(@name)
-        iteration = context.registers[:cycle][key].to_i
-
-        val = context.evaluate(@variables[iteration])
-
-        if val.is_a?(Array)
-          val = val.join
-        elsif !val.is_a?(String)
-          val = val.to_s
-        end
-
-        output << val
-
+        iteration = context.registers[:cycle][key]
+        result = context.evaluate(@variables[iteration])
         iteration += 1
         iteration  = 0 if iteration >= @variables.size
         context.registers[:cycle][key] = iteration
+        result
       end
-
-      output
     end
 
     private
@@ -64,12 +51,6 @@ module Liquid
         $1 ? Expression.parse($1) : nil
       end.compact
     end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        Array(@node.variables)
-      end
-    end
   end
 
   Template.register_tag('cycle', Cycle)

lib/liquid/tags/decrement.rb

@@ -23,14 +23,11 @@ module Liquid
       @variable = markup.strip
     end
 
-    attr_reader :variable
-
-    def render_to_output_buffer(context, output)
+    def render(context)
       value = context.environments.first[@variable] ||= 0
       value -= 1
       context.environments.first[@variable] = value
-      output << value.to_s
-      output
+      value.to_s
     end
   end
 

lib/liquid/tags/for.rb

@@ -46,8 +46,6 @@ module Liquid
   class For < Block
     Syntax = /\A(#{VariableSegment}+)\s+in\s+(#{QuotedFragment}+)\s*(reversed)?/o
 
-    attr_reader :collection_name, :variable_name, :limit, :from, :for_block, :else_block, :name, :reversed
-
     def initialize(tag_name, markup, options)
       super
       @from = @limit = nil
@@ -70,16 +68,14 @@ module Liquid
       @else_block = BlockBody.new
     end
 
-    def render_to_output_buffer(context, output)
+    def render(context)
       segment = collection_segment(context)
 
       if segment.empty?
-        render_else(context, output)
+        render_else(context)
       else
-        render_segment(context, output, segment)
+        render_segment(context, segment)
       end
-
-      output
     end
 
     protected
@@ -121,28 +117,19 @@ module Liquid
     private
 
     def collection_segment(context)
-      offsets = context.registers[:for] ||= {}
+      offsets = context.registers[:for] ||= Hash.new(0)
 
       from = if @from == :continue
         offsets[@name].to_i
       else
-        from_value = context.evaluate(@from)
-        if from_value.nil?
-          0
-        else
-          Utils.to_integer(from_value)
-        end
+        context.evaluate(@from).to_i
       end
 
       collection = context.evaluate(@collection_name)
       collection = collection.to_a if collection.is_a?(Range)
 
-      limit_value = context.evaluate(@limit)
-      to = if limit_value.nil?
-        nil
-      else
-        Utils.to_integer(limit_value) + from
-      end
+      limit = context.evaluate(@limit)
+      to = limit ? limit.to_i + from : nil
 
       segment = Utils.slice_collection(collection, from, to)
       segment.reverse! if @reversed
@@ -152,10 +139,12 @@ module Liquid
       segment
     end
 
-    def render_segment(context, output, segment)
+    def render_segment(context, segment)
       for_stack = context.registers[:for_stack] ||= []
       length = segment.length
 
+      result = ''
+
       context.stack do
         loop_vars = Liquid::ForloopDrop.new(@name, length, for_stack[-1])
 
@@ -164,9 +153,9 @@ module Liquid
         begin
           context['forloop'.freeze] = loop_vars
 
-          segment.each do |item|
+          segment.each_with_index do |item, index|
             context[@variable_name] = item
-            @for_block.render_to_output_buffer(context, output)
+            result << @for_block.render(context)
             loop_vars.send(:increment!)
 
             # Handle any interrupts if they exist.
@@ -181,7 +170,7 @@ module Liquid
         end
       end
 
-      output
+      result
     end
 
     def set_attribute(key, expr)
@@ -197,18 +186,8 @@ module Liquid
       end
     end
 
-    def render_else(context, output)
-      if @else_block
-        @else_block.render_to_output_buffer(context, output)
-      else
-        output
-      end
-    end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        (super + [@node.limit, @node.from, @node.collection_name]).compact
-      end
+    def render_else(context)
+      @else_block ? @else_block.render(context) : ''.freeze
     end
   end
 

lib/liquid/tags/if.rb

@@ -12,9 +12,7 @@ module Liquid
   class If < Block
     Syntax = /(#{QuotedFragment})\s*([=!<>a-z_]+)?\s*(#{QuotedFragment})?/o
     ExpressionsAndOperators = /(?:\b(?:\s?and\s?|\s?or\s?)\b|(?:\s*(?!\b(?:\s?and\s?|\s?or\s?)\b)(?:#{QuotedFragment}|\S+)\s*)+)/o
-    BOOLEAN_OPERATORS = %w(and or).freeze
-
-    attr_reader :blocks
+    BOOLEAN_OPERATORS = %w(and or)
 
     def initialize(tag_name, markup, options)
       super
@@ -22,15 +20,15 @@ module Liquid
       push_block('if'.freeze, markup)
     end
 
-    def nodelist
-      @blocks.map(&:attachment)
-    end
-
     def parse(tokens)
       while parse_body(@blocks.last.attachment, tokens)
       end
     end
 
+    def nodelist
+      @blocks.map(&:attachment)
+    end
+
     def unknown_tag(tag, markup, tokens)
       if ['elsif'.freeze, 'else'.freeze].include?(tag)
         push_block(tag, markup)
@@ -39,16 +37,15 @@ module Liquid
       end
     end
 
-    def render_to_output_buffer(context, output)
+    def render(context)
       context.stack do
         @blocks.each do |block|
           if block.evaluate(context)
-            return block.attachment.render_to_output_buffer(context, output)
+            return block.attachment.render(context)
           end
         end
+        ''.freeze
       end
-
-      output
     end
 
     private
@@ -86,20 +83,17 @@ module Liquid
 
     def strict_parse(markup)
       p = Parser.new(markup)
-      condition = parse_binary_comparisons(p)
+      condition = parse_binary_comparison(p)
       p.consume(:end_of_string)
       condition
     end
 
-    def parse_binary_comparisons(p)
+    def parse_binary_comparison(p)
       condition = parse_comparison(p)
-      first_condition = condition
-      while op = (p.id?('and'.freeze) || p.id?('or'.freeze))
-        child_condition = parse_comparison(p)
-        condition.send(op, child_condition)
-        condition = child_condition
+      if op = (p.id?('and'.freeze) || p.id?('or'.freeze))
+        condition.send(op, parse_binary_comparison(p))
       end
-      first_condition
+      condition
     end
 
     def parse_comparison(p)
@@ -111,12 +105,6 @@ module Liquid
         Condition.new(a)
       end
     end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        @node.blocks
-      end
-    end
   end
 
   Template.register_tag('if'.freeze, If)

lib/liquid/tags/ifchanged.rb

@@ -1,17 +1,16 @@
 module Liquid
   class Ifchanged < Block
-    def render_to_output_buffer(context, output)
+    def render(context)
       context.stack do
-        block_output = ''
-        super(context, block_output)
+        output = super
 
-        if block_output != context.registers[:ifchanged]
-          context.registers[:ifchanged] = block_output
-          output << block_output
+        if output != context.registers[:ifchanged]
+          context.registers[:ifchanged] = output
+          output
+        else
+          ''.freeze
         end
       end
-
-      output
     end
   end
 

lib/liquid/tags/include.rb

@@ -16,8 +16,6 @@ module Liquid
   class Include < Tag
     Syntax = /(#{QuotedFragment}+)(\s+(?:with|for)\s+(#{QuotedFragment}+))?/o
 
-    attr_reader :template_name_expr, :variable_name_expr, :attributes
-
     def initialize(tag_name, markup, options)
       super
 
@@ -42,7 +40,7 @@ module Liquid
     def parse(_tokens)
     end
 
-    def render_to_output_buffer(context, output)
+    def render(context)
       template_name = context.evaluate(@template_name_expr)
       raise ArgumentError.new(options[:locale].t("errors.argument.include")) unless template_name
 
@@ -66,21 +64,19 @@ module Liquid
           end
 
           if variable.is_a?(Array)
-            variable.each do |var|
+            variable.collect do |var|
               context[context_variable_name] = var
-              partial.render_to_output_buffer(context, output)
+              partial.render(context)
             end
           else
             context[context_variable_name] = variable
-            partial.render_to_output_buffer(context, output)
+            partial.render(context)
           end
         end
       ensure
         context.template_name = old_template_name
         context.partial = old_partial
       end
-
-      output
     end
 
     private
@@ -111,15 +107,6 @@ module Liquid
 
       file_system.read_template_file(context.evaluate(@template_name_expr))
     end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        [
-          @node.template_name_expr,
-          @node.variable_name_expr
-        ] + @node.attributes.values
-      end
-    end
   end
 
   Template.register_tag('include'.freeze, Include)

lib/liquid/tags/increment.rb

@@ -20,13 +20,10 @@ module Liquid
       @variable = markup.strip
     end
 
-    attr_reader :variable
-
-    def render_to_output_buffer(context, output)
+    def render(context)
       value = context.environments.first[@variable] ||= 0
       context.environments.first[@variable] = value + 1
-      output << value.to_s
-      output
+      value.to_s
     end
   end
 

lib/liquid/tags/raw.rb

@@ -3,8 +3,6 @@ module Liquid
     Syntax = /\A\s*\z/
     FullTokenPossiblyInvalid = /\A(.*)#{TagStart}\s*(\w+)\s*(.*)?#{TagEnd}\z/om
 
-    attr_reader :body
-
     def initialize(tag_name, markup, parse_context)
       super
 
@@ -24,9 +22,8 @@ module Liquid
       raise SyntaxError.new(parse_context.locale.t("errors.syntax.tag_never_closed".freeze, block_name: block_name))
     end
 
-    def render_to_output_buffer(_context, output)
-      output << @body
-      output
+    def render(_context)
+      @body
     end
 
     def nodelist

lib/liquid/tags/table_row.rb

@@ -2,8 +2,6 @@ module Liquid
   class TableRow < Block
     Syntax = /(\w+)\s+in\s+(#{QuotedFragment}+)/o
 
-    attr_reader :variable_name, :collection_name, :attributes
-
     def initialize(tag_name, markup, options)
       super
       if markup =~ Syntax
@@ -18,7 +16,7 @@ module Liquid
       end
     end
 
-    def render_to_output_buffer(context, output)
+    def render(context)
       collection = context.evaluate(@collection_name) or return ''.freeze
 
       from = @attributes.key?('offset'.freeze) ? context.evaluate(@attributes['offset'.freeze]).to_i : 0
@@ -30,34 +28,25 @@ module Liquid
 
       cols = context.evaluate(@attributes['cols'.freeze]).to_i
 
-      output << "<tr class=\"row1\">\n"
+      result = "<tr class=\"row1\">\n"
       context.stack do
         tablerowloop = Liquid::TablerowloopDrop.new(length, cols)
         context['tablerowloop'.freeze] = tablerowloop
 
-        collection.each do |item|
+        collection.each_with_index do |item, index|
           context[@variable_name] = item
 
-          output << "<td class=\"col#{tablerowloop.col}\">"
-          super
-          output << '</td>'
+          result << "<td class=\"col#{tablerowloop.col}\">" << super << '</td>'
 
           if tablerowloop.col_last && !tablerowloop.last
-            output << "</tr>\n<tr class=\"row#{tablerowloop.row + 1}\">"
+            result << "</tr>\n<tr class=\"row#{tablerowloop.row + 1}\">"
           end
 
           tablerowloop.send(:increment!)
         end
       end
-
-      output << "</tr>\n"
-      output
-    end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        super + @node.attributes.values + [@node.collection_name]
-      end
+      result << "</tr>\n"
+      result
     end
   end
 

lib/liquid/tags/unless.rb

@@ -6,23 +6,23 @@ module Liquid
   #   {% unless x < 0 %} x is greater than zero {% endunless %}
   #
   class Unless < If
-    def render_to_output_buffer(context, output)
+    def render(context)
       context.stack do
         # First condition is interpreted backwards ( if not )
         first_block = @blocks.first
         unless first_block.evaluate(context)
-          return first_block.attachment.render_to_output_buffer(context, output)
+          return first_block.attachment.render(context)
         end
 
         # After the first condition unless works just like if
         @blocks[1..-1].each do |block|
           if block.evaluate(context)
-            return block.attachment.render_to_output_buffer(context, output)
+            return block.attachment.render(context)
           end
         end
-      end
 
-      output
+        ''.freeze
+      end
     end
   end
 

lib/liquid/template.rb

@@ -50,7 +50,7 @@ module Liquid
       private
 
       def lookup_class(name)
-        Object.const_get(name)
+        name.split("::").reject(&:empty?).reduce(Object) { |scope, const| scope.const_get(const) }
       end
     end
 
@@ -187,12 +187,9 @@ module Liquid
         raise ArgumentError, "Expected Hash or Liquid::Context as parameter"
       end
 
-      output = nil
-
       case args.last
       when Hash
         options = args.pop
-        output = options[:output] if options[:output]
 
         registers.merge!(options[:registers]) if options[:registers].is_a?(Hash)
 
@@ -206,10 +203,11 @@ module Liquid
 
       begin
         # render the nodelist.
-
-        with_profiling(context) do
-          @root.render_to_output_buffer(context, output || '')
+        # for performance reasons we get an array back here. join will make a string out of it.
+        result = with_profiling(context) do
+          @root.render(context)
         end
+        result.respond_to?(:join) ? result.join : result
       rescue Liquid::MemoryError => e
         context.handle_error(e)
       ensure
@@ -222,10 +220,6 @@ module Liquid
       render(*args)
     end
 
-    def render_to_output_buffer(context, output)
-      render(context, output: output)
-    end
-
     private
 
     def tokenize(source)

lib/liquid/utils.rb

@@ -46,11 +46,11 @@ module Liquid
     def self.to_number(obj)
       case obj
       when Float
-        BigDecimal(obj.to_s)
+        BigDecimal.new(obj.to_s)
       when Numeric
         obj
       when String
-        (obj.strip =~ /\A-?\d+\.\d+\z/) ? BigDecimal(obj) : obj.to_i
+        (obj.strip =~ /\A-?\d+\.\d+\z/) ? BigDecimal.new(obj) : obj.to_i
       else
         if obj.respond_to?(:to_number)
           obj.to_number

lib/liquid/variable.rb

@@ -10,16 +10,10 @@ module Liquid
   #   {{ user | link }}
   #
   class Variable
-    FilterMarkupRegex = /#{FilterSeparator}\s*(.*)/om
     FilterParser = /(?:\s+|#{QuotedFragment}|#{ArgumentSeparator})+/o
-    FilterArgsRegex = /(?:#{FilterArgumentSeparator}|#{ArgumentSeparator})\s*((?:\w+\s*\:\s*)?#{QuotedFragment})/o
-    JustTagAttributes = /\A#{TagAttributes}\z/o
-    MarkupWithQuotedFragment = /(#{QuotedFragment})(.*)/om
-
     attr_accessor :filters, :name, :line_number
     attr_reader :parse_context
     alias_method :options, :parse_context
-
     include ParserSwitching
 
     def initialize(markup, parse_context)
@@ -41,17 +35,17 @@ module Liquid
 
     def lax_parse(markup)
       @filters = []
-      return unless markup =~ MarkupWithQuotedFragment
+      return unless markup =~ /(#{QuotedFragment})(.*)/om
 
       name_markup = $1
       filter_markup = $2
       @name = Expression.parse(name_markup)
-      if filter_markup =~ FilterMarkupRegex
+      if filter_markup =~ /#{FilterSeparator}\s*(.*)/om
         filters = $1.scan(FilterParser)
         filters.each do |f|
           next unless f =~ /\w+/
           filtername = Regexp.last_match(0)
-          filterargs = f.scan(FilterArgsRegex).flatten
+          filterargs = f.scan(/(?:#{FilterArgumentSeparator}|#{ArgumentSeparator})\s*((?:\w+\s*\:\s*)?#{QuotedFragment})/o).flatten
           @filters << parse_filter_expressions(filtername, filterargs)
         end
       end
@@ -85,38 +79,26 @@ module Liquid
       end
 
       obj = context.apply_global_filter(obj)
+
       taint_check(context, obj)
+
       obj
     end
 
-    def render_to_output_buffer(context, output)
-      obj = render(context)
-
-      if obj.is_a?(Array)
-        output << obj.join
-      elsif obj.nil?
-      else
-        output << obj.to_s
-      end
-
-      output
-    end
-
     private
 
     def parse_filter_expressions(filter_name, unparsed_args)
       filter_args = []
-      keyword_args = nil
+      keyword_args = {}
       unparsed_args.each do |a|
-        if matches = a.match(JustTagAttributes)
-          keyword_args ||= {}
+        if matches = a.match(/\A#{TagAttributes}\z/o)
           keyword_args[matches[1]] = Expression.parse(matches[2])
         else
           filter_args << Expression.parse(a)
         end
       end
       result = [filter_name, filter_args]
-      result << keyword_args if keyword_args
+      result << keyword_args unless keyword_args.empty?
       result
     end
 
@@ -150,11 +132,5 @@ module Liquid
         raise error
       end
     end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        [@node.name] + @node.filters.flatten
-      end
-    end
   end
 end

lib/liquid/variable_lookup.rb

@@ -1,9 +1,9 @@
 module Liquid
   class VariableLookup
     SQUARE_BRACKETED = /\A\[(.*)\]\z/m
-    COMMAND_METHODS = ['size'.freeze, 'first'.freeze, 'last'.freeze].freeze
+    COMMAND_METHODS = ['size'.freeze, 'first'.freeze, 'last'.freeze]
 
-    attr_reader :name, :lookups, :command_flags
+    attr_reader :name, :lookups
 
     def self.parse(markup)
       new(markup)
@@ -78,11 +78,5 @@ module Liquid
     def state
       [@name, @lookups, @command_flags]
     end
-
-    class ParseTreeVisitor < Liquid::ParseTreeVisitor
-      def children
-        @node.lookups
-      end
-    end
   end
 end

lib/liquid/version.rb

@@ -1,5 +1,4 @@
 # encoding: utf-8
-
 module Liquid
-  VERSION = "4.0.3".freeze
+  VERSION = "4.0.0"
 end

liquid.gemspec

@@ -1,5 +1,4 @@
 # encoding: utf-8
-
 lib = File.expand_path('../lib/', __FILE__)
 $LOAD_PATH.unshift lib unless $LOAD_PATH.include?(lib)
 

performance/benchmark.rb

@@ -1,16 +1,7 @@
 require 'benchmark/ips'
 require_relative 'theme_runner'
 
-case ARGV.first.to_sym
-when :lax
-  Liquid::Template.error_mode = ARGV.first.to_sym if ARGV.first
-when :strict
-  Liquid::Template.error_mode = ARGV.first.to_sym if ARGV.first
-when :superfluid
-  require 'liquid/superfluid'
-  Liquid::Template.error_mode = :strict
-end
-
+Liquid::Template.error_mode = ARGV.first.to_sym if ARGV.first
 profiler = ThemeRunner.new
 
 Benchmark.ips do |x|

performance/memory_profile.rb

@@ -1,26 +0,0 @@
-# frozen_string_literal: true
-
-requirf 'benchmark/ips'
-require 'memory_profiler'
-require_relative 'theme_runner'
-
-def profile(phase, &block)
-  puts
-  puts "#{phase}:"
-  puts
-
-  report = MemoryProfiler.report(&block)
-
-  report.pretty_print(
-    color_output: true,
-    scale_bytes: true,
-    detailed_report: true
-  )
-end
-
-Liquid::Template.error_mode = ARGV.first.to_sym if ARGV.first
-
-profiler = ThemeRunner.new
-
-profile("Parsing") { profiler.compile }
-profile("Rendering") { profiler.render }

performance/shopify/comment_form.rb

@@ -12,7 +12,7 @@ class CommentForm < Liquid::Block
     end
   end
 
-  def render_to_output_buffer(context, output)
+  def render(context)
     article = context[@variable_name]
 
     context.stack do
@@ -23,9 +23,7 @@ class CommentForm < Liquid::Block
         'email'  => context['comment.email'],
         'body'   => context['comment.body']
       }
-
-      output << wrap_in_form(article, render_all(@nodelist, context, output))
-      output
+      wrap_in_form(article, render_all(@nodelist, context))
     end
   end
 

performance/shopify/paginate.rb

@@ -21,7 +21,7 @@ class Paginate < Liquid::Block
     end
   end
 
-  def render_to_output_buffer(context, output)
+  def render(context)
     @context = context
 
     context.stack do

test/integration/blank_test.rb

@@ -1,10 +1,11 @@
 require 'test_helper'
 
 class FoobarTag < Liquid::Tag
-  def render_to_output_buffer(context, output)
-    output << ' '
-    output
+  def render(*args)
+    " "
   end
+
+  Liquid::Template.register_tag('foobar', FoobarTag)
 end
 
 class BlankTestFileSystem
@@ -30,9 +31,7 @@ class BlankTest < Minitest::Test
   end
 
   def test_new_tags_are_not_blank_by_default
-    with_custom_tag('foobar', FoobarTag) do
-      assert_template_result(" " * N, wrap_in_for("{% foobar %}"))
-    end
+    assert_template_result(" " * N, wrap_in_for("{% foobar %}"))
   end
 
   def test_loops_are_blank

test/integration/block_test.rb

@@ -1,12 +0,0 @@
-require 'test_helper'
-
-class BlockTest < Minitest::Test
-  include Liquid
-
-  def test_unexpected_end_tag
-    exc = assert_raises(SyntaxError) do
-      Template.parse("{% if true %}{% endunless %}")
-    end
-    assert_equal exc.message, "Liquid syntax error: 'endunless' is not a valid delimiter for if tags. use endif"
-  end
-end

test/integration/error_handling_test.rb

@@ -123,7 +123,7 @@ class ErrorHandlingTest < Minitest::Test
             ',
       error_mode: :warn,
       line_numbers: true
-    )
+                                     )
 
     assert_equal ['Liquid syntax error (line 4): Unexpected character = in "1 =! 2"'],
       template.warnings.map(&:message)
@@ -140,7 +140,7 @@ class ErrorHandlingTest < Minitest::Test
                 ',
         error_mode: :strict,
         line_numbers: true
-      )
+                            )
     end
 
     assert_equal 'Liquid syntax error (line 4): Unexpected character = in "1 =! 2"', err.message
@@ -158,7 +158,7 @@ class ErrorHandlingTest < Minitest::Test
           bla
                 ',
         line_numbers: true
-      )
+                            )
     end
 
     assert_equal "Liquid syntax error (line 5): Unknown tag 'foo'", err.message

test/integration/parse_tree_visitor_test.rb

@@ -1,247 +0,0 @@
-# frozen_string_literal: true
-
-require 'test_helper'
-
-class ParseTreeVisitorTest < Minitest::Test
-  include Liquid
-
-  def test_variable
-    assert_equal(
-      ["test"],
-      visit(%({{ test }}))
-    )
-  end
-
-  def test_varible_with_filter
-    assert_equal(
-      ["test", "infilter"],
-      visit(%({{ test | split: infilter }}))
-    )
-  end
-
-  def test_dynamic_variable
-    assert_equal(
-      ["test", "inlookup"],
-      visit(%({{ test[inlookup] }}))
-    )
-  end
-
-  def test_if_condition
-    assert_equal(
-      ["test"],
-      visit(%({% if test %}{% endif %}))
-    )
-  end
-
-  def test_complex_if_condition
-    assert_equal(
-      ["test"],
-      visit(%({% if 1 == 1 and 2 == test %}{% endif %}))
-    )
-  end
-
-  def test_if_body
-    assert_equal(
-      ["test"],
-      visit(%({% if 1 == 1 %}{{ test }}{% endif %}))
-    )
-  end
-
-  def test_unless_condition
-    assert_equal(
-      ["test"],
-      visit(%({% unless test %}{% endunless %}))
-    )
-  end
-
-  def test_complex_unless_condition
-    assert_equal(
-      ["test"],
-      visit(%({% unless 1 == 1 and 2 == test %}{% endunless %}))
-    )
-  end
-
-  def test_unless_body
-    assert_equal(
-      ["test"],
-      visit(%({% unless 1 == 1 %}{{ test }}{% endunless %}))
-    )
-  end
-
-  def test_elsif_condition
-    assert_equal(
-      ["test"],
-      visit(%({% if 1 == 1 %}{% elsif test %}{% endif %}))
-    )
-  end
-
-  def test_complex_elsif_condition
-    assert_equal(
-      ["test"],
-      visit(%({% if 1 == 1 %}{% elsif 1 == 1 and 2 == test %}{% endif %}))
-    )
-  end
-
-  def test_elsif_body
-    assert_equal(
-      ["test"],
-      visit(%({% if 1 == 1 %}{% elsif 2 == 2 %}{{ test }}{% endif %}))
-    )
-  end
-
-  def test_else_body
-    assert_equal(
-      ["test"],
-      visit(%({% if 1 == 1 %}{% else %}{{ test }}{% endif %}))
-    )
-  end
-
-  def test_case_left
-    assert_equal(
-      ["test"],
-      visit(%({% case test %}{% endcase %}))
-    )
-  end
-
-  def test_case_condition
-    assert_equal(
-      ["test"],
-      visit(%({% case 1 %}{% when test %}{% endcase %}))
-    )
-  end
-
-  def test_case_when_body
-    assert_equal(
-      ["test"],
-      visit(%({% case 1 %}{% when 2 %}{{ test }}{% endcase %}))
-    )
-  end
-
-  def test_case_else_body
-    assert_equal(
-      ["test"],
-      visit(%({% case 1 %}{% else %}{{ test }}{% endcase %}))
-    )
-  end
-
-  def test_for_in
-    assert_equal(
-      ["test"],
-      visit(%({% for x in test %}{% endfor %}))
-    )
-  end
-
-  def test_for_limit
-    assert_equal(
-      ["test"],
-      visit(%({% for x in (1..5) limit: test %}{% endfor %}))
-    )
-  end
-
-  def test_for_offset
-    assert_equal(
-      ["test"],
-      visit(%({% for x in (1..5) offset: test %}{% endfor %}))
-    )
-  end
-
-  def test_for_body
-    assert_equal(
-      ["test"],
-      visit(%({% for x in (1..5) %}{{ test }}{% endfor %}))
-    )
-  end
-
-  def test_tablerow_in
-    assert_equal(
-      ["test"],
-      visit(%({% tablerow x in test %}{% endtablerow %}))
-    )
-  end
-
-  def test_tablerow_limit
-    assert_equal(
-      ["test"],
-      visit(%({% tablerow x in (1..5) limit: test %}{% endtablerow %}))
-    )
-  end
-
-  def test_tablerow_offset
-    assert_equal(
-      ["test"],
-      visit(%({% tablerow x in (1..5) offset: test %}{% endtablerow %}))
-    )
-  end
-
-  def test_tablerow_body
-    assert_equal(
-      ["test"],
-      visit(%({% tablerow x in (1..5) %}{{ test }}{% endtablerow %}))
-    )
-  end
-
-  def test_cycle
-    assert_equal(
-      ["test"],
-      visit(%({% cycle test %}))
-    )
-  end
-
-  def test_assign
-    assert_equal(
-      ["test"],
-      visit(%({% assign x = test %}))
-    )
-  end
-
-  def test_capture
-    assert_equal(
-      ["test"],
-      visit(%({% capture x %}{{ test }}{% endcapture %}))
-    )
-  end
-
-  def test_include
-    assert_equal(
-      ["test"],
-      visit(%({% include test %}))
-    )
-  end
-
-  def test_include_with
-    assert_equal(
-      ["test"],
-      visit(%({% include "hai" with test %}))
-    )
-  end
-
-  def test_include_for
-    assert_equal(
-      ["test"],
-      visit(%({% include "hai" for test %}))
-    )
-  end
-
-  def test_preserve_tree_structure
-    assert_equal(
-      [[nil, [
-        [nil, [[nil, [["other", []]]]]],
-        ["test", []],
-        ["xs", []]
-      ]]],
-      traversal(%({% for x in xs offset: test %}{{ other }}{% endfor %})).visit
-    )
-  end
-
-  private
-
-  def traversal(template)
-    ParseTreeVisitor
-      .for(Template.parse(template).root)
-      .add_callback_for(VariableLookup, &:name)
-  end
-
-  def visit(template)
-    traversal(template).visit.flatten.compact
-  end
-end

test/integration/parsing_quirks_test.rb

@@ -99,7 +99,7 @@ class ParsingQuirksTest < Minitest::Test
       # After the messed up quotes a filter without parameters (reverse) should work
       # but one with parameters (remove) shouldn't be detected.
       assert_template_result('here',  "{{ 'hi there' | split:\"t\"\" | reverse | first}}")
-      assert_template_result('hi ', "{{ 'hi there' | split:\"t\"\" | remove:\"i\" | first}}")
+      assert_template_result('hi ',  "{{ 'hi there' | split:\"t\"\" | remove:\"i\" | first}}")
     end
   end
 

test/integration/security_test.rb

@@ -63,18 +63,4 @@ class SecurityTest < Minitest::Test
 
     assert_equal [], (Symbol.all_symbols - current_symbols)
   end
-
-  def test_max_depth_nested_blocks_does_not_raise_exception
-    depth = Liquid::Block::MAX_DEPTH
-    code = "{% if true %}" * depth + "rendered" + "{% endif %}" * depth
-    assert_equal "rendered", Template.parse(code).render!
-  end
-
-  def test_more_than_max_depth_nested_blocks_raises_exception
-    depth = Liquid::Block::MAX_DEPTH + 1
-    code = "{% if true %}" * depth + "rendered" + "{% endif %}" * depth
-    assert_raises(Liquid::StackLevelError) do
-      Template.parse(code).render!
-    end
-  end
 end # SecurityTest

test/integration/standard_filter_test.rb

@@ -128,16 +128,8 @@ class StandardFiltersTest < Minitest::Test
 
   def test_escape
     assert_equal '&lt;strong&gt;', @filters.escape('<strong>')
-    assert_equal '1', @filters.escape(1)
-    assert_equal '2001-02-03', @filters.escape(Date.new(2001, 2, 3))
-    assert_nil @filters.escape(nil)
-  end
-
-  def test_h
+    assert_equal nil, @filters.escape(nil)
     assert_equal '&lt;strong&gt;', @filters.h('<strong>')
-    assert_equal '1', @filters.h(1)
-    assert_equal '2001-02-03', @filters.h(Date.new(2001, 2, 3))
-    assert_nil @filters.h(nil)
   end
 
   def test_escape_once
@@ -146,22 +138,14 @@ class StandardFiltersTest < Minitest::Test
 
   def test_url_encode
     assert_equal 'foo%2B1%40example.com', @filters.url_encode('foo+1@example.com')
-    assert_equal '1', @filters.url_encode(1)
-    assert_equal '2001-02-03', @filters.url_encode(Date.new(2001, 2, 3))
-    assert_nil @filters.url_encode(nil)
+    assert_equal nil, @filters.url_encode(nil)
   end
 
   def test_url_decode
     assert_equal 'foo bar', @filters.url_decode('foo+bar')
     assert_equal 'foo bar', @filters.url_decode('foo%20bar')
     assert_equal 'foo+1@example.com', @filters.url_decode('foo%2B1%40example.com')
-    assert_equal '1', @filters.url_decode(1)
-    assert_equal '2001-02-03', @filters.url_decode(Date.new(2001, 2, 3))
-    assert_nil @filters.url_decode(nil)
-    exception = assert_raises Liquid::ArgumentError do
-      @filters.url_decode('%ff')
-    end
-    assert_equal 'Liquid error: invalid byte sequence in UTF-8', exception.message
+    assert_equal nil, @filters.url_decode(nil)
   end
 
   def test_truncatewords
@@ -181,9 +165,6 @@ class StandardFiltersTest < Minitest::Test
     assert_equal 'test', @filters.strip_html("<div\nclass='multiline'>test</div>")
     assert_equal 'test', @filters.strip_html("<!-- foo bar \n test -->test")
     assert_equal '', @filters.strip_html(nil)
-
-    # Quirk of the existing implementation
-    assert_equal 'foo;', @filters.strip_html("<<<script </script>script>foo;</script>")
   end
 
   def test_join
@@ -197,11 +178,6 @@ class StandardFiltersTest < Minitest::Test
     assert_equal [{ "a" => 1 }, { "a" => 2 }, { "a" => 3 }, { "a" => 4 }], @filters.sort([{ "a" => 4 }, { "a" => 3 }, { "a" => 1 }, { "a" => 2 }], "a")
   end
 
-  def test_sort_with_nils
-    assert_equal [1, 2, 3, 4, nil], @filters.sort([nil, 4, 3, 2, 1])
-    assert_equal [{ "a" => 1 }, { "a" => 2 }, { "a" => 3 }, { "a" => 4 }, {}], @filters.sort([{ "a" => 4 }, { "a" => 3 }, {}, { "a" => 1 }, { "a" => 2 }], "a")
-  end
-
   def test_sort_when_property_is_sometimes_missing_puts_nils_last
     input = [
       { "price" => 4, "handle" => "alpha" },
@@ -220,89 +196,14 @@ class StandardFiltersTest < Minitest::Test
     assert_equal expectation, @filters.sort(input, "price")
   end
 
-  def test_sort_natural
-    assert_equal ["a", "B", "c", "D"], @filters.sort_natural(["c", "D", "a", "B"])
-    assert_equal [{ "a" => "a" }, { "a" => "B" }, { "a" => "c" }, { "a" => "D" }], @filters.sort_natural([{ "a" => "D" }, { "a" => "c" }, { "a" => "a" }, { "a" => "B" }], "a")
-  end
-
-  def test_sort_natural_with_nils
-    assert_equal ["a", "B", "c", "D", nil], @filters.sort_natural([nil, "c", "D", "a", "B"])
-    assert_equal [{ "a" => "a" }, { "a" => "B" }, { "a" => "c" }, { "a" => "D" }, {}], @filters.sort_natural([{ "a" => "D" }, { "a" => "c" }, {}, { "a" => "a" }, { "a" => "B" }], "a")
-  end
-
-  def test_sort_natural_when_property_is_sometimes_missing_puts_nils_last
-    input = [
-      { "price" => "4", "handle" => "alpha" },
-      { "handle" => "beta" },
-      { "price" => "1", "handle" => "gamma" },
-      { "handle" => "delta" },
-      { "price" => 2, "handle" => "epsilon" }
-    ]
-    expectation = [
-      { "price" => "1", "handle" => "gamma" },
-      { "price" => 2, "handle" => "epsilon" },
-      { "price" => "4", "handle" => "alpha" },
-      { "handle" => "delta" },
-      { "handle" => "beta" }
-    ]
-    assert_equal expectation, @filters.sort_natural(input, "price")
-  end
-
-  def test_sort_natural_case_check
-    input = [
-      { "key" => "X" },
-      { "key" => "Y" },
-      { "key" => "Z" },
-      { "fake" => "t" },
-      { "key" => "a" },
-      { "key" => "b" },
-      { "key" => "c" }
-    ]
-    expectation = [
-      { "key" => "a" },
-      { "key" => "b" },
-      { "key" => "c" },
-      { "key" => "X" },
-      { "key" => "Y" },
-      { "key" => "Z" },
-      { "fake" => "t" }
-    ]
-    assert_equal expectation, @filters.sort_natural(input, "key")
-    assert_equal ["a", "b", "c", "X", "Y", "Z"], @filters.sort_natural(["X", "Y", "Z", "a", "b", "c"])
-  end
-
   def test_sort_empty_array
     assert_equal [], @filters.sort([], "a")
   end
 
-  def test_sort_invalid_property
-    foo = [
-      [1],
-      [2],
-      [3]
-    ]
-
-    assert_raises Liquid::ArgumentError do
-      @filters.sort(foo, "bar")
-    end
-  end
-
   def test_sort_natural_empty_array
     assert_equal [], @filters.sort_natural([], "a")
   end
 
-  def test_sort_natural_invalid_property
-    foo = [
-      [1],
-      [2],
-      [3]
-    ]
-
-    assert_raises Liquid::ArgumentError do
-      @filters.sort_natural(foo, "bar")
-    end
-  end
-
   def test_legacy_sort_hash
     assert_equal [{ a: 1, b: 2 }], @filters.sort({ a: 1, b: 2 })
   end
@@ -326,34 +227,10 @@ class StandardFiltersTest < Minitest::Test
     assert_equal [], @filters.uniq([], "a")
   end
 
-  def test_uniq_invalid_property
-    foo = [
-      [1],
-      [2],
-      [3]
-    ]
-
-    assert_raises Liquid::ArgumentError do
-      @filters.uniq(foo, "bar")
-    end
-  end
-
   def test_compact_empty_array
     assert_equal [], @filters.compact([], "a")
   end
 
-  def test_compact_invalid_property
-    foo = [
-      [1],
-      [2],
-      [3]
-    ]
-
-    assert_raises Liquid::ArgumentError do
-      @filters.compact(foo, "bar")
-    end
-  end
-
   def test_reverse
     assert_equal [4, 3, 2, 1], @filters.reverse([1, 2, 3, 4])
   end
@@ -419,29 +296,6 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result "123", '{{ foo | map: "foo" }}', "foo" => TestEnumerable.new
   end
 
-  def test_map_returns_empty_on_2d_input_array
-    foo = [
-      [1],
-      [2],
-      [3]
-    ]
-
-    assert_raises Liquid::ArgumentError do
-      @filters.map(foo, "bar")
-    end
-  end
-
-  def test_map_returns_empty_with_no_property
-    foo = [
-      [1],
-      [2],
-      [3]
-    ]
-    assert_raises Liquid::ArgumentError do
-      @filters.map(foo, nil)
-    end
-  end
-
   def test_sort_works_on_enumerables
     assert_template_result "213", '{{ foo | sort: "bar" | map: "foo" }}', "foo" => TestEnumerable.new
   end
@@ -472,11 +326,11 @@ class StandardFiltersTest < Minitest::Test
     assert_equal '07/05/2006', @filters.date("2006-07-05 10:00:00", "%m/%d/%Y")
 
     assert_equal "07/16/2004", @filters.date("Fri Jul 16 01:00:00 2004", "%m/%d/%Y")
-    assert_equal Date.today.year.to_s, @filters.date('now', '%Y')
-    assert_equal Date.today.year.to_s, @filters.date('today', '%Y')
-    assert_equal Date.today.year.to_s, @filters.date('Today', '%Y')
+    assert_equal "#{Date.today.year}", @filters.date('now', '%Y')
+    assert_equal "#{Date.today.year}", @filters.date('today', '%Y')
+    assert_equal "#{Date.today.year}", @filters.date('Today', '%Y')
 
-    assert_nil @filters.date(nil, "%B")
+    assert_equal nil, @filters.date(nil, "%B")
 
     assert_equal '', @filters.date('', "%B")
 
@@ -489,8 +343,8 @@ class StandardFiltersTest < Minitest::Test
   def test_first_last
     assert_equal 1, @filters.first([1, 2, 3])
     assert_equal 3, @filters.last([1, 2, 3])
-    assert_nil @filters.first([])
-    assert_nil @filters.last([])
+    assert_equal nil, @filters.first([])
+    assert_equal nil, @filters.last([])
   end
 
   def test_replace
@@ -630,28 +484,6 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result "5", "{{ price | floor }}", 'price' => NumberLikeThing.new(5.4)
   end
 
-  def test_at_most
-    assert_template_result "4", "{{ 5 | at_most:4 }}"
-    assert_template_result "5", "{{ 5 | at_most:5 }}"
-    assert_template_result "5", "{{ 5 | at_most:6 }}"
-
-    assert_template_result "4.5", "{{ 4.5 | at_most:5 }}"
-    assert_template_result "5", "{{ width | at_most:5 }}", 'width' => NumberLikeThing.new(6)
-    assert_template_result "4", "{{ width | at_most:5 }}", 'width' => NumberLikeThing.new(4)
-    assert_template_result "4", "{{ 5 | at_most: width }}", 'width' => NumberLikeThing.new(4)
-  end
-
-  def test_at_least
-    assert_template_result "5", "{{ 5 | at_least:4 }}"
-    assert_template_result "5", "{{ 5 | at_least:5 }}"
-    assert_template_result "6", "{{ 5 | at_least:6 }}"
-
-    assert_template_result "5", "{{ 4.5 | at_least:5 }}"
-    assert_template_result "6", "{{ width | at_least:5 }}", 'width' => NumberLikeThing.new(6)
-    assert_template_result "5", "{{ width | at_least:5 }}", 'width' => NumberLikeThing.new(4)
-    assert_template_result "6", "{{ 5 | at_least: width }}", 'width' => NumberLikeThing.new(6)
-  end
-
   def test_append
     assigns = { 'a' => 'bc', 'b' => 'd' }
     assert_template_result('bcd', "{{ a | append: 'd'}}", assigns)
@@ -692,78 +524,6 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result('abc', "{{ 'abc' | date: '%D' }}")
   end
 
-  def test_where
-    input = [
-      { "handle" => "alpha", "ok" => true },
-      { "handle" => "beta", "ok" => false },
-      { "handle" => "gamma", "ok" => false },
-      { "handle" => "delta", "ok" => true }
-    ]
-
-    expectation = [
-      { "handle" => "alpha", "ok" => true },
-      { "handle" => "delta", "ok" => true }
-    ]
-
-    assert_equal expectation, @filters.where(input, "ok", true)
-    assert_equal expectation, @filters.where(input, "ok")
-  end
-
-  def test_where_no_key_set
-    input = [
-      { "handle" => "alpha", "ok" => true },
-      { "handle" => "beta" },
-      { "handle" => "gamma" },
-      { "handle" => "delta", "ok" => true }
-    ]
-
-    expectation = [
-      { "handle" => "alpha", "ok" => true },
-      { "handle" => "delta", "ok" => true }
-    ]
-
-    assert_equal expectation, @filters.where(input, "ok", true)
-    assert_equal expectation, @filters.where(input, "ok")
-  end
-
-  def test_where_non_array_map_input
-    assert_equal [{ "a" => "ok" }], @filters.where({ "a" => "ok" }, "a", "ok")
-    assert_equal [], @filters.where({ "a" => "not ok" }, "a", "ok")
-  end
-
-  def test_where_indexable_but_non_map_value
-    assert_raises(Liquid::ArgumentError) { @filters.where(1, "ok", true) }
-    assert_raises(Liquid::ArgumentError) { @filters.where(1, "ok") }
-  end
-
-  def test_where_non_boolean_value
-    input = [
-      { "message" => "Bonjour!", "language" => "French" },
-      { "message" => "Hello!", "language" => "English" },
-      { "message" => "Hallo!", "language" => "German" }
-    ]
-
-    assert_equal [{ "message" => "Bonjour!", "language" => "French" }], @filters.where(input, "language", "French")
-    assert_equal [{ "message" => "Hallo!", "language" => "German" }], @filters.where(input, "language", "German")
-    assert_equal [{ "message" => "Hello!", "language" => "English" }], @filters.where(input, "language", "English")
-  end
-
-  def test_where_array_of_only_unindexable_values
-    assert_nil @filters.where([nil], "ok", true)
-    assert_nil @filters.where([nil], "ok")
-  end
-
-  def test_where_no_target_value
-    input = [
-      { "foo" => false },
-      { "foo" => true },
-      { "foo" => "for sure" },
-      { "bar" => true }
-    ]
-
-    assert_equal [{ "foo" => true }, { "foo" => "for sure" }], @filters.where(input, "foo")
-  end
-
   private
 
   def with_timezone(tz)

test/integration/tags/for_tag_test.rb

@@ -103,34 +103,6 @@ HERE
     assert_template_result('3456', '{%for i in array limit: 4 offset: 2 %}{{ i }}{%endfor%}', assigns)
   end
 
-  def test_limiting_with_invalid_limit
-    assigns = { 'array' => [1, 2, 3, 4, 5, 6, 7, 8, 9, 0] }
-    template = <<-MKUP
-      {% for i in array limit: true offset: 1 %}
-        {{ i }}
-      {% endfor %}
-    MKUP
-
-    exception = assert_raises(Liquid::ArgumentError) do
-      Template.parse(template).render!(assigns)
-    end
-    assert_equal("Liquid error: invalid integer", exception.message)
-  end
-
-  def test_limiting_with_invalid_offset
-    assigns = { 'array' => [1, 2, 3, 4, 5, 6, 7, 8, 9, 0] }
-    template = <<-MKUP
-      {% for i in array limit: 1 offset: true %}
-        {{ i }}
-      {% endfor %}
-    MKUP
-
-    exception = assert_raises(Liquid::ArgumentError) do
-      Template.parse(template).render!(assigns)
-    end
-    assert_equal("Liquid error: invalid integer", exception.message)
-  end
-
   def test_dynamic_variable_limiting
     assigns = { 'array' => [1, 2, 3, 4, 5, 6, 7, 8, 9, 0] }
     assigns['limit'] = 2
@@ -187,7 +159,7 @@ HERE
     assert_template_result(expected, markup, assigns)
   end
 
-  def test_pause_resume_big_limit
+  def test_pause_resume_BIG_limit
     assigns = { 'array' => { 'items' => [1, 2, 3, 4, 5, 6, 7, 8, 9, 0] } }
     markup = <<-MKUP
       {%for i in array.items limit:3 %}{{i}}{%endfor%}
@@ -206,7 +178,7 @@ HERE
     assert_template_result(expected, markup, assigns)
   end
 
-  def test_pause_resume_big_offset
+  def test_pause_resume_BIG_offset
     assigns = { 'array' => { 'items' => [1, 2, 3, 4, 5, 6, 7, 8, 9, 0] } }
     markup = '{%for i in array.items limit:3 %}{{i}}{%endfor%}
       next

test/integration/tags/include_tag_test.rb

@@ -30,9 +30,6 @@ class TestFileSystem
     when 'assignments'
       "{% assign foo = 'bar' %}"
 
-    when 'break'
-      "{% break %}"
-
     else
       template_path
     end
@@ -66,9 +63,8 @@ class CustomInclude < Liquid::Tag
   def parse(tokens)
   end
 
-  def render_to_output_buffer(context, output)
-    output << @template_name[1..-2]
-    output
+  def render(context)
+    @template_name[1..-2]
   end
 end
 
@@ -141,7 +137,7 @@ class IncludeTagTest < Minitest::Test
 
     Liquid::Template.file_system = infinite_file_system.new
 
-    assert_raises(Liquid::StackLevelError) do
+    assert_raises(Liquid::StackLevelError, SystemStackError) do
       Template.parse("{% include 'loop' %}").render!
     end
   end
@@ -246,9 +242,4 @@ class IncludeTagTest < Minitest::Test
 
     assert_equal [], template.errors
   end
-
-  def test_break_through_include
-    assert_template_result "1", "{% for i in (1..3) %}{{ i }}{% break %}{{ i }}{% endfor %}"
-    assert_template_result "1", "{% for i in (1..3) %}{{ i }}{% include 'break' %}{{ i }}{% endfor %}"
-  end
 end # IncludeTagTest

test/integration/template_test.rb

@@ -139,16 +139,6 @@ class TemplateTest < Minitest::Test
     refute_nil t.resource_limits.assign_score
   end
 
-  def test_resource_limits_assign_score_counts_bytes_not_characters
-    t = Template.parse("{% assign foo = 'すごい' %}")
-    t.render
-    assert_equal 9, t.resource_limits.assign_score
-
-    t = Template.parse("{% capture foo %}すごい{% endcapture %}")
-    t.render
-    assert_equal 9, t.resource_limits.assign_score
-  end
-
   def test_resource_limits_assign_score_nested
     t = Template.parse("{% assign foo = 'aaaa' | reverse %}")
 
@@ -197,14 +187,6 @@ class TemplateTest < Minitest::Test
     assert_equal "ababab", t.render
   end
 
-  def test_render_length_uses_number_of_bytes_not_characters
-    t = Template.parse("{% if true %}すごい{% endif %}")
-    t.resource_limits.render_length_limit = 10
-    assert_equal "Liquid error: Memory limits exceeded", t.render
-    t.resource_limits.render_length_limit = 18
-    assert_equal "すごい", t.render
-  end
-
   def test_default_resource_limits_unaffected_by_render_with_context
     context = Context.new
     t = Template.parse("{% for a in (1..100) %} {% assign foo = 1 %} {% endfor %}")
@@ -279,15 +261,6 @@ class TemplateTest < Minitest::Test
     assert_equal 'Liquid error: undefined variable d', t.errors[2].message
   end
 
-  def test_nil_value_does_not_raise
-    Liquid::Template.error_mode = :strict
-    t = Template.parse("some{{x}}thing")
-    result = t.render!({ 'x' => nil }, strict_variables: true)
-
-    assert_equal 0, t.errors.count
-    assert_equal 'something', result
-  end
-
   def test_undefined_variables_raise
     t = Template.parse("{{x}} {{y}} {{z.a}} {{z.b}} {{z.c.d}}")
 

test/integration/trim_mode_test.rb

@@ -496,10 +496,6 @@ class TrimModeTest < Minitest::Test
     assert_template_result(expected, text)
   end
 
-  def test_right_trim_followed_by_tag
-    assert_template_result('ab c', '{{ "a" -}}{{ "b" }} c')
-  end
-
   def test_raw_output
     whitespace = '        '
     text = <<-END_TEMPLATE

test/integration/variable_test.rb

@@ -89,8 +89,4 @@ class VariableTest < Minitest::Test
   def test_multiline_variable
     assert_equal 'worked', Template.parse("{{\ntest\n}}").render!('test' => 'worked')
   end
-
-  def test_render_symbol
-    assert_template_result 'bar', '{{ foo }}', 'foo' => :bar
-  end
 end

test/test_helper.rb

@@ -2,6 +2,7 @@
 
 ENV["MT_NO_EXPECTATIONS"] = "1"
 require 'minitest/autorun'
+require 'spy/integration'
 
 $LOAD_PATH.unshift(File.join(File.expand_path(__dir__), '..', 'lib'))
 require 'liquid.rb'
@@ -19,11 +20,6 @@ if ENV['LIQUID-C'] == '1'
   require 'liquid/c'
 end
 
-if ENV['SUPERFLUID'] == '1'
-  puts "-- SUPERFLUID"
-  require 'liquid/superfluid'
-end
-
 if Minitest.const_defined?('Test')
   # We're on Minitest 5+. Nothing to do here.
 else
@@ -89,13 +85,6 @@ module Minitest
     ensure
       Liquid::Template.error_mode = old_mode
     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)
-    end
   end
 end
 

test/unit/block_unit_test.rb

@@ -44,47 +44,10 @@ class BlockUnitTest < Minitest::Test
   end
 
   def test_with_custom_tag
-    with_custom_tag('testtag', Block) do
-      assert Liquid::Template.parse("{% testtag %} {% endtesttag %}")
-    end
-  end
-
-  def test_custom_block_tags_have_a_default_render_to_output_buffer_method_for_backwards_compatibility
-    klass1 = Class.new(Block) do
-      def render(*)
-        'hello'
-      end
-    end
-
-    with_custom_tag('blabla', klass1) do
-      template = Liquid::Template.parse("{% blabla %} bla {% endblabla %}")
-
-      assert_equal 'hello', template.render
-
-      buf = ''
-      output = template.render({}, output: buf)
-      assert_equal 'hello', output
-      assert_equal 'hello', buf
-      assert_equal buf.object_id, output.object_id
-    end
-
-    klass2 = Class.new(klass1) do
-      def render(*)
-        'foo' + super + 'bar'
-      end
-    end
-
-    with_custom_tag('blabla', klass2) do
-      template = Liquid::Template.parse("{% blabla %} foo {% endblabla %}")
-
-      assert_equal 'foohellobar', template.render
-
-      buf = ''
-      output = template.render({}, output: buf)
-      assert_equal 'foohellobar', output
-      assert_equal 'foohellobar', buf
-      assert_equal buf.object_id, output.object_id
-    end
+    Liquid::Template.register_tag("testtag", Block)
+    assert Liquid::Template.parse("{% testtag %} {% endtesttag %}")
+  ensure
+    Liquid::Template.tags.delete('testtag')
   end
 
   private

test/unit/condition_unit_test.rb

@@ -24,9 +24,9 @@ class ConditionUnitTest < Minitest::Test
     assert_evaluates_true 1, '<=', 1
     # negative numbers
     assert_evaluates_true 1, '>', -1
-    assert_evaluates_true -1, '<', 1
+    assert_evaluates_true (-1), '<', 1
     assert_evaluates_true 1.0, '>', -1.0
-    assert_evaluates_true -1.0, '<', 1.0
+    assert_evaluates_true (-1.0), '<', 1.0
   end
 
   def test_default_operators_evalute_false
@@ -65,8 +65,8 @@ class ConditionUnitTest < Minitest::Test
   end
 
   def test_hash_compare_backwards_compatibility
-    assert_nil Condition.new({}, '>', 2).evaluate
-    assert_nil Condition.new(2, '>', {}).evaluate
+    assert_equal nil, Condition.new({}, '>', 2).evaluate
+    assert_equal nil, Condition.new(2, '>', {}).evaluate
     assert_equal false, Condition.new({}, '==', 2).evaluate
     assert_equal true, Condition.new({ 'a' => 1 }, '==', { 'a' => 1 }).evaluate
     assert_equal true, Condition.new({ 'a' => 2 }, 'contains', 'a').evaluate
@@ -130,6 +130,17 @@ class ConditionUnitTest < Minitest::Test
     assert_equal false, condition.evaluate
   end
 
+  def test_maximum_recursion_depth
+    condition = Condition.new(1, '==', 1)
+
+    assert_raises(Liquid::StackLevelError) do
+      (1..510).each do
+        condition.evaluate
+        condition.and Condition.new(2, '==', 2)
+      end
+    end
+  end
+
   def test_should_allow_custom_proc_operator
     Condition.operators['starts_with'] = proc { |cond, left, right| left =~ %r{^#{right}} }
 

test/unit/context_unit_test.rb

@@ -70,6 +70,10 @@ class ContextUnitTest < Minitest::Test
     @context = Liquid::Context.new
   end
 
+  def teardown
+    Spy.teardown
+  end
+
   def test_variables
     @context['string'] = 'string'
     assert_equal 'string', @context['string']
@@ -94,12 +98,12 @@ class ContextUnitTest < Minitest::Test
     assert_equal false, @context['bool']
 
     @context['nil'] = nil
-    assert_nil @context['nil']
-    assert_nil @context['nil']
+    assert_equal nil, @context['nil']
+    assert_equal nil, @context['nil']
   end
 
   def test_variables_not_existing
-    assert_nil @context['does_not_exist']
+    assert_equal nil, @context['does_not_exist']
   end
 
   def test_scoping
@@ -181,7 +185,7 @@ class ContextUnitTest < Minitest::Test
     @context['test'] = 'test'
     assert_equal 'test', @context['test']
     @context.pop
-    assert_nil @context['test']
+    assert_equal nil, @context['test']
   end
 
   def test_hierachical_data
@@ -296,7 +300,7 @@ class ContextUnitTest < Minitest::Test
     @context['hash'] = { 'first' => 'Hello' }
 
     assert_equal 1, @context['array.first']
-    assert_nil @context['array["first"]']
+    assert_equal nil, @context['array["first"]']
     assert_equal 'Hello', @context['hash["first"]']
   end
 
@@ -446,10 +450,14 @@ class ContextUnitTest < Minitest::Test
     assert_equal @context, @context['category'].context
   end
 
-  def test_interrupt_avoids_object_allocations
-    assert_no_object_allocations do
-      @context.interrupt?
-    end
+  def test_use_empty_instead_of_any_in_interrupt_handling_to_avoid_lots_of_unnecessary_object_allocations
+    mock_any = Spy.on_instance_method(Array, :any?)
+    mock_empty = Spy.on_instance_method(Array, :empty?)
+
+    @context.interrupt?
+
+    refute mock_any.has_been_called?
+    assert mock_empty.has_been_called?
   end
 
   def test_context_initialization_with_a_proc_in_environment
@@ -472,18 +480,4 @@ class ContextUnitTest < Minitest::Test
     context = Context.new
     assert_equal 'hi', context.apply_global_filter('hi')
   end
-
-  private
-
-  def assert_no_object_allocations
-    unless RUBY_ENGINE == 'ruby'
-      skip "stackprof needed to count object allocations"
-    end
-    require 'stackprof'
-
-    profile = StackProf.run(mode: :object) do
-      yield
-    end
-    assert_equal 0, profile[:samples]
-  end
 end # ContextTest

test/unit/tag_unit_test.rb

@@ -18,42 +18,4 @@ class TagUnitTest < Minitest::Test
     tag = Tag.parse("some_tag", "", Tokenizer.new(""), ParseContext.new)
     assert_equal 'some_tag', tag.tag_name
   end
-
-  def test_custom_tags_have_a_default_render_to_output_buffer_method_for_backwards_compatibility
-    klass1 = Class.new(Tag) do
-      def render(*)
-        'hello'
-      end
-    end
-
-    with_custom_tag('blabla', klass1) do
-      template = Liquid::Template.parse("{% blabla %}")
-
-      assert_equal 'hello', template.render
-
-      buf = ''
-      output = template.render({}, output: buf)
-      assert_equal 'hello', output
-      assert_equal 'hello', buf
-      assert_equal buf.object_id, output.object_id
-    end
-
-    klass2 = Class.new(klass1) do
-      def render(*)
-        'foo' + super + 'bar'
-      end
-    end
-
-    with_custom_tag('blabla', klass2) do
-      template = Liquid::Template.parse("{% blabla %}")
-
-      assert_equal 'foohellobar', template.render
-
-      buf = ''
-      output = template.render({}, output: buf)
-      assert_equal 'foohellobar', output
-      assert_equal 'foohellobar', buf
-      assert_equal buf.object_id, output.object_id
-    end
-  end
 end