Follow Shopify ruby style

This is the first step in bringing Liquid style inline with Shopify ruby style

.rubocop.yml

@@ -1,131 +1,15 @@
 inherit_from:
+  - https://shopify.github.io/ruby-style-guide/rubocop.yml
   - .rubocop_todo.yml
-  - ./.rubocop_todo.yml
+
+require: rubocop-performance
+
+Performance:
+  Enabled: true
 
 AllCops:
   Exclude:
-    - 'performance/shopify/*'
+    - 'vendor/bundle/**/*'
-    - 'pkg/**'
-
-Metrics/BlockNesting:
-  Max: 3
-
-Metrics/ModuleLength:
-  Enabled: false
-
-Metrics/ClassLength:
-  Enabled: false
-
-Lint/AssignmentInCondition:
-  Enabled: false
-
-Lint/AmbiguousOperator:
-  Enabled: false
-
-Lint/AmbiguousRegexpLiteral:
-  Enabled: false
-
-Lint/ParenthesesAsGroupedExpression:
-  Enabled: false
-
-Lint/UnusedBlockArgument:
-  Enabled: false
-
-Layout/EndAlignment:
-  EnforcedStyleAlignWith: variable
-
-Lint/UnusedMethodArgument:
-  Enabled: false
-
-Style/SingleLineBlockParams:
-  Enabled: false
-
-Style/DoubleNegation:
-  Enabled: false
-
-Style/StringLiteralsInInterpolation:
-  Enabled: false
-
-Style/AndOr:
-  Enabled: false
-
-Style/SignalException:
-  Enabled: false
-
-Style/StringLiterals:
-  Enabled: false
-
-Style/BracesAroundHashParameters:
-  Enabled: false
-
-Style/NumericLiterals:
-  Enabled: false
-
-Layout/SpaceInsideArrayLiteralBrackets:
-  Enabled: false
-
-Layout/SpaceBeforeBlockBraces:
-  Enabled: false
-
-Style/Documentation:
-  Enabled: false
-
-Style/ClassAndModuleChildren:
-  Enabled: false
-
-Style/TrailingCommaInArrayLiteral:
-  Enabled: false
-
-Style/TrailingCommaInHashLiteral:
-  Enabled: false
-
-Layout/IndentHash:
-  EnforcedStyle: consistent
-
-Style/FormatString:
-  Enabled: false
-
-Layout/AlignParameters:
-  EnforcedStyle: with_fixed_indentation
-
-Layout/MultilineOperationIndentation:
-  EnforcedStyle: indented
-
-Style/IfUnlessModifier:
-  Enabled: false
-
-Style/RaiseArgs:
-  Enabled: false
-
-Style/PreferredHashMethods:
-  Enabled: false
-
-Style/RegexpLiteral:
-  Enabled: false
-
-Style/SymbolLiteral:
-  Enabled: false
-
-Performance/Count:
-  Enabled: false
-
-Naming/ConstantName:
-  Enabled: false
-
-Layout/CaseIndentation:
-  Enabled: false
-
-Style/ClassVars:
-  Enabled: false
-
-Style/PerlBackrefs:
-  Enabled: false
-
-Style/TrivialAccessors:
-  AllowPredicates: true
-
-Style/WordArray:
-  Enabled: false
       
 Naming/MethodName:
   Exclude:

.rubocop_todo.yml

@@ -1,23 +1,37 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2019-04-22 19:11:24 -0400 using RuboCop version 0.53.0.
+# on 2019-08-29 12:16:25 +1000 using RuboCop version 0.74.0.
 # 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
+# Offense count: 13
 # Cop supports --auto-correct.
-# Configuration parameters: Include, TreatCommentsAsGroupSeparators.
+# Configuration parameters: AllowMultipleStyles, EnforcedHashRocketStyle, EnforcedColonStyle, EnforcedLastArgumentHashStyle.
-# Include: **/*.gemspec
+# SupportedHashRocketStyles: key, separator, table
-Gemspec/OrderedDependencies:
+# SupportedColonStyles: key, separator, table
+# SupportedLastArgumentHashStyles: always_inspect, always_ignore, ignore_implicit, ignore_explicit
+Layout/AlignHash:
   Exclude:
-    - 'liquid.gemspec'
+    - 'lib/liquid/condition.rb'
+    - 'lib/liquid/expression.rb'
+    - 'performance/shopify/comment_form.rb'
+    - 'performance/shopify/database.rb'
+    - 'performance/shopify/paginate.rb'
+    - 'test/unit/context_unit_test.rb'
+
+# Offense count: 3
+# Cop supports --auto-correct.
+# Configuration parameters: AllowForAlignment, AllowBeforeTrailingComments, ForceEqualSignAlignment.
+Layout/ExtraSpacing:
+  Exclude:
+    - 'performance/shopify/paginate.rb'
 
 # Offense count: 5
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
-# SupportedStyles: auto_detection, squiggly, active_support, powerpack, unindent
+# SupportedStyles: squiggly, active_support, powerpack, unindent
 Layout/IndentHeredoc:
   Exclude:
     - 'test/integration/tags/for_tag_test.rb'
@@ -32,6 +46,62 @@ Layout/MultilineMethodCallBraceLayout:
     - 'test/integration/error_handling_test.rb'
     - 'test/unit/strainer_unit_test.rb'
 
+# Offense count: 4
+# Cop supports --auto-correct.
+# Configuration parameters: AllowForAlignment.
+Layout/SpaceAroundOperators:
+  Exclude:
+    - 'lib/liquid/condition.rb'
+    - 'performance/shopify/paginate.rb'
+
+# Offense count: 9
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, EnforcedStyleForEmptyBraces.
+# SupportedStyles: space, no_space
+# SupportedStylesForEmptyBraces: space, no_space
+Layout/SpaceBeforeBlockBraces:
+  Exclude:
+    - 'example/server/server.rb'
+    - 'lib/liquid/variable.rb'
+    - 'test/integration/drop_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+    - 'test/integration/tags/if_else_tag_test.rb'
+
+# Offense count: 19
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, EnforcedStyleForEmptyBrackets.
+# SupportedStyles: space, no_space, compact
+# SupportedStylesForEmptyBrackets: space, no_space
+Layout/SpaceInsideArrayLiteralBrackets:
+  Exclude:
+    - 'test/integration/drop_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+    - 'test/integration/tags/for_tag_test.rb'
+    - 'test/integration/tags/include_tag_test.rb'
+    - 'test/integration/tags/standard_tag_test.rb'
+    - 'test/unit/context_unit_test.rb'
+
+# Offense count: 2
+Lint/AmbiguousOperator:
+  Exclude:
+    - 'test/unit/condition_unit_test.rb'
+
+# Offense count: 16
+# Configuration parameters: AllowSafeAssignment.
+Lint/AssignmentInCondition:
+  Exclude:
+    - 'lib/liquid/block_body.rb'
+    - 'lib/liquid/lexer.rb'
+    - 'lib/liquid/standardfilters.rb'
+    - 'lib/liquid/tags/for.rb'
+    - 'lib/liquid/tags/if.rb'
+    - 'lib/liquid/tags/include.rb'
+    - 'lib/liquid/tags/raw.rb'
+    - 'lib/liquid/variable.rb'
+    - 'performance/profile.rb'
+    - 'test/test_helper.rb'
+    - 'test/unit/tokenizer_unit_test.rb'
+
 # Offense count: 2
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
@@ -40,145 +110,184 @@ Lint/InheritException:
   Exclude:
     - 'lib/liquid/interrupts.rb'
 
+# Offense count: 10
+# Cop supports --auto-correct.
+# Configuration parameters: IgnoreEmptyBlocks, AllowUnusedKeywordArguments.
+Lint/UnusedBlockArgument:
+  Exclude:
+    - 'lib/liquid/condition.rb'
+    - 'lib/liquid/context.rb'
+    - 'lib/liquid/document.rb'
+    - 'lib/liquid/parse_context.rb'
+    - 'lib/liquid/template.rb'
+    - 'performance/shopify/json_filter.rb'
+    - 'test/integration/filter_test.rb'
+    - 'test/integration/render_profiling_test.rb'
+    - 'test/integration/variable_test.rb'
+    - 'test/unit/condition_unit_test.rb'
+
+# Offense count: 12
+# Cop supports --auto-correct.
+# Configuration parameters: AllowUnusedKeywordArguments, IgnoreEmptyMethods.
+Lint/UnusedMethodArgument:
+  Exclude:
+    - 'example/server/liquid_servlet.rb'
+    - 'test/integration/blank_test.rb'
+    - 'test/integration/error_handling_test.rb'
+    - 'test/integration/filter_test.rb'
+    - 'test/integration/output_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+    - 'test/integration/tags/include_tag_test.rb'
+    - 'test/unit/strainer_unit_test.rb'
+
+# Offense count: 2
+Lint/UselessAssignment:
+  Exclude:
+    - 'performance/shopify/database.rb'
+
 # Offense count: 1
 # Configuration parameters: CheckForMethodsWithNoSideEffects.
 Lint/Void:
   Exclude:
     - 'lib/liquid/parse_context.rb'
 
-# Offense count: 53
+# Offense count: 95
-Metrics/AbcSize:
+# Cop supports --auto-correct.
-  Max: 56
+# Configuration parameters: AutoCorrect, AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
+# URISchemes: http, https
+Metrics/LineLength:
+  Max: 294
 
-# Offense count: 12
+# Offense count: 44
-Metrics/CyclomaticComplexity:
+Naming/ConstantName:
-  Max: 13
-
-# Offense count: 112
-# Configuration parameters: CountComments.
-Metrics/MethodLength:
-  Max: 38
-
-# Offense count: 8
-Metrics/PerceivedComplexity:
-  Max: 11
-
-# Offense count: 52
-# Configuration parameters: Blacklist.
-# Blacklist: END, (?-mix:EO[A-Z]{1})
-Naming/HeredocDelimiterNaming:
   Exclude:
-    - 'test/integration/assign_test.rb'
+    - 'lib/liquid.rb'
-    - 'test/integration/capture_test.rb'
+    - 'lib/liquid/block_body.rb'
-    - 'test/integration/trim_mode_test.rb'
+    - 'lib/liquid/tags/assign.rb'
-
+    - 'lib/liquid/tags/capture.rb'
-# Offense count: 23
+    - 'lib/liquid/tags/case.rb'
-# Configuration parameters: MinNameLength, AllowNamesEndingInNumbers, AllowedNames, ForbiddenNames.
+    - 'lib/liquid/tags/cycle.rb'
-# AllowedNames: io, id
+    - 'lib/liquid/tags/for.rb'
-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/tags/include.rb'
+    - 'lib/liquid/tags/raw.rb'
+    - 'lib/liquid/tags/table_row.rb'
     - 'lib/liquid/variable.rb'
-    - 'test/integration/filter_test.rb'
+    - 'performance/shopify/comment_form.rb'
-    - 'test/integration/standard_filter_test.rb'
+    - 'performance/shopify/paginate.rb'
-    - 'test/integration/tags/for_tag_test.rb'
+    - 'test/integration/tags/include_tag_test.rb'
-    - 'test/integration/template_test.rb'
-    - 'test/unit/condition_unit_test.rb'
 
-# Offense count: 12
+# Offense count: 2
+# Configuration parameters: .
+# SupportedStyles: snake_case, camelCase
+Naming/MethodName:
+  EnforcedStyle: snake_case
+
+# Offense count: 3
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
-# SupportedStyles: prefer_alias, prefer_alias_method
+# SupportedStyles: always, conditionals
-Style/Alias:
+Style/AndOr:
   Exclude:
-    - 'lib/liquid/drop.rb'
     - 'lib/liquid/i18n.rb'
-    - 'lib/liquid/profiler/hooks.rb'
+    - 'lib/liquid/tags/table_row.rb'
-    - 'lib/liquid/standardfilters.rb'
+    - 'lib/liquid/tokenizer.rb'
-    - 'lib/liquid/tag.rb'
-    - 'lib/liquid/tags/include.rb'
-    - 'lib/liquid/variable.rb'
 
-# Offense count: 22
+# Offense count: 40
-Style/CommentedKeyword:
+# Cop supports --auto-correct.
-  Enabled: false
+# Configuration parameters: EnforcedStyle.
+# SupportedStyles: braces, no_braces, context_dependent
+Style/BracesAroundHashParameters:
+  Exclude:
+    - 'test/integration/error_handling_test.rb'
+    - 'test/integration/filter_test.rb'
+    - 'test/integration/render_profiling_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+    - 'test/integration/tags/echo_test.rb'
+    - 'test/integration/tags/increment_tag_test.rb'
+    - 'test/integration/tags/standard_tag_test.rb'
+    - 'test/integration/template_test.rb'
+    - 'test/unit/condition_unit_test.rb'
+    - 'test/unit/context_unit_test.rb'
 
-# Offense count: 1
+# Offense count: 5
+Style/ClassVars:
+  Exclude:
+    - 'lib/liquid/condition.rb'
+    - 'lib/liquid/strainer.rb'
+    - 'lib/liquid/template.rb'
+
+# Offense count: 2
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, SingleLineConditionsOnly, IncludeTernaryExpressions.
 # SupportedStyles: assign_to_condition, assign_inside_condition
 Style/ConditionalAssignment:
   Exclude:
     - 'lib/liquid/errors.rb'
+    - 'performance/shopify/shop_filter.rb'
 
 # Offense count: 1
+# Configuration parameters: AllowCoercion.
 Style/DateTime:
   Exclude:
     - 'test/unit/context_unit_test.rb'
 
 # Offense count: 2
 # Cop supports --auto-correct.
+Style/EachWithObject:
+  Exclude:
+    - 'performance/shopify/database.rb'
+
+# Offense count: 1
+# Cop supports --auto-correct.
 Style/EmptyCaseCondition:
   Exclude:
-    - 'lib/liquid/block_body.rb'
     - 'lib/liquid/lexer.rb'
 
-# Offense count: 5
+# Offense count: 1
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle.
-# SupportedStyles: compact, expanded
+# SupportedStyles: each, for
-Style/EmptyMethod:
+Style/For:
   Exclude:
-    - 'lib/liquid/tag.rb'
+    - 'performance/shopify/shop_filter.rb'
-    - 'lib/liquid/tags/comment.rb'
-    - 'lib/liquid/tags/include.rb'
-    - 'test/integration/tags/include_tag_test.rb'
-    - 'test/unit/context_unit_test.rb'
 
-# Offense count: 3
+# Offense count: 9
 # 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
+# SupportedStyles: format, sprintf, percent
-Style/FormatStringToken:
+Style/FormatString:
   Exclude:
+    - 'example/server/example_servlet.rb'
+    - 'performance/shopify/money_filter.rb'
+    - 'performance/shopify/weight_filter.rb'
     - 'test/integration/filter_test.rb'
     - 'test/integration/hash_ordering_test.rb'
 
-# Offense count: 14
+# Offense count: 115
-# Configuration parameters: MinBodyLength.
+# Cop supports --auto-correct.
-Style/GuardClause:
+# Configuration parameters: EnforcedStyle.
+# SupportedStyles: always, never
+Style/FrozenStringLiteralComment:
+  Enabled: false
+
+# Offense count: 30
+# Cop supports --auto-correct.
+# Configuration parameters: IgnoreMacros, IgnoredMethods, IncludedMacros, AllowParenthesesInMultilineCall, AllowParenthesesInChaining, AllowParenthesesInCamelCaseMethod, EnforcedStyle.
+# SupportedStyles: require_parentheses, omit_parentheses
+Style/MethodCallWithArgsParentheses:
   Exclude:
-    - 'lib/liquid/condition.rb'
+    - 'Gemfile'
-    - 'lib/liquid/lexer.rb'
+    - 'Rakefile'
-    - 'lib/liquid/strainer.rb'
+    - 'lib/liquid/block_body.rb'
-    - 'lib/liquid/tags/assign.rb'
+    - 'lib/liquid/parser.rb'
-    - 'lib/liquid/tags/capture.rb'
-    - 'lib/liquid/tags/case.rb'
     - 'lib/liquid/tags/for.rb'
-    - 'lib/liquid/tags/include.rb'
+    - 'liquid.gemspec'
-    - 'lib/liquid/tags/raw.rb'
+    - 'performance/shopify/database.rb'
-    - 'lib/liquid/tags/table_row.rb'
+    - 'performance/shopify/liquid.rb'
-    - 'lib/liquid/variable.rb'
+    - 'test/test_helper.rb'
-    - 'test/unit/tokenizer_unit_test.rb'
+    - 'test/unit/condition_unit_test.rb'
+    - 'test/unit/tags/if_tag_unit_test.rb'
 
 # Offense count: 1
 # Cop supports --auto-correct.
@@ -188,27 +297,17 @@ Style/Next:
   Exclude:
     - 'lib/liquid/tags/for.rb'
 
-# Offense count: 4
+# Offense count: 52
 # Cop supports --auto-correct.
-# Configuration parameters: AutoCorrect, EnforcedStyle.
+Style/PerlBackrefs:
-# SupportedStyles: predicate, comparison
+  Enabled: false
-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
+# Offense count: 33
 # Cop supports --auto-correct.
-# Configuration parameters: PreferredDelimiters.
+# Configuration parameters: EnforcedStyle.
-Style/PercentLiteralDelimiters:
+# SupportedStyles: compact, exploded
-  Exclude:
+Style/RaiseArgs:
-    - 'lib/liquid/tags/if.rb'
+  Enabled: false
-    - 'liquid.gemspec'
-    - 'test/integration/assign_test.rb'
-    - 'test/integration/standard_filter_test.rb'
 
 # Offense count: 1
 # Cop supports --auto-correct.
@@ -216,21 +315,52 @@ Style/RedundantSelf:
   Exclude:
     - 'lib/liquid/strainer.rb'
 
-# Offense count: 9
+# Offense count: 5
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, AllowInnerSlashes.
+# SupportedStyles: slashes, percent_r, mixed
+Style/RegexpLiteral:
+  Exclude:
+    - 'lib/liquid/file_system.rb'
+    - 'lib/liquid/standardfilters.rb'
+    - 'performance/shopify/shop_filter.rb'
+    - 'test/unit/condition_unit_test.rb'
+
+# Offense count: 3
+# Cop supports --auto-correct.
+# Configuration parameters: ConvertCodeThatCanStartToReturnNil, Whitelist.
+# Whitelist: present?, blank?, presence, try, try!
+Style/SafeNavigation:
+  Exclude:
+    - 'lib/liquid/drop.rb'
+    - 'lib/liquid/strainer.rb'
+    - 'lib/liquid/tokenizer.rb'
+
+# Offense count: 10
 # Cop supports --auto-correct.
 # Configuration parameters: AllowAsExpressionSeparator.
 Style/Semicolon:
   Exclude:
+    - 'performance/shopify/database.rb'
     - 'test/integration/error_handling_test.rb'
     - 'test/integration/template_test.rb'
     - 'test/unit/context_unit_test.rb'
 
-# Offense count: 7
+# Offense count: 1
 # Cop supports --auto-correct.
-# Configuration parameters: MinSize.
+# Configuration parameters: EnforcedStyle.
-# SupportedStyles: percent, brackets
+# SupportedStyles: use_perl_names, use_english_names
-Style/SymbolArray:
+Style/SpecialGlobalVars:
-  EnforcedStyle: brackets
+  Exclude:
+    - 'performance/shopify/liquid.rb'
+
+# Offense count: 2
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle.
+# SupportedStyles: single_quotes, double_quotes
+Style/StringLiteralsInInterpolation:
+  Exclude:
+    - 'performance/shopify/tag_filter.rb'
 
 # Offense count: 2
 # Cop supports --auto-correct.
@@ -241,6 +371,33 @@ Style/TernaryParentheses:
     - 'lib/liquid/context.rb'
     - 'lib/liquid/utils.rb'
 
+# Offense count: 21
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyleForMultiline.
+# SupportedStylesForMultiline: comma, consistent_comma, no_comma
+Style/TrailingCommaInArrayLiteral:
+  Exclude:
+    - 'lib/liquid/parse_tree_visitor.rb'
+    - 'lib/liquid/tags/include.rb'
+    - 'test/integration/parse_tree_visitor_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+
+# Offense count: 9
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyleForMultiline.
+# SupportedStylesForMultiline: comma, consistent_comma, no_comma
+Style/TrailingCommaInHashLiteral:
+  Exclude:
+    - 'lib/liquid/condition.rb'
+    - 'lib/liquid/lexer.rb'
+    - 'lib/liquid/standardfilters.rb'
+    - 'performance/shopify/comment_form.rb'
+    - 'performance/shopify/database.rb'
+    - 'performance/shopify/paginate.rb'
+    - 'performance/theme_runner.rb'
+    - 'test/integration/output_test.rb'
+    - 'test/unit/context_unit_test.rb'
+
 # Offense count: 2
 # Cop supports --auto-correct.
 Style/UnneededPercentQ:
@@ -252,9 +409,3 @@ Style/UnneededPercentQ:
 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

.travis.yml

@@ -1,20 +1,14 @@
 language: ruby
 
 rvm:
-  - 2.1
-  - 2.2
-  - 2.3
   - 2.4
   - 2.5
   - &latest_ruby 2.6
+  - 2.7
   - ruby-head
   - jruby-head
-#  - rbx-2
+  - truffleruby
 
-addons:
-  apt:
-    packages:
-    - libgmp3-dev
 
 matrix:
   include:
@@ -24,9 +18,9 @@ matrix:
   allow_failures:
     - rvm: ruby-head
     - rvm: jruby-head
+    - rvm: truffleruby
 
-install:
+cache: bundler
-  - bundle install
 
 script: bundle exec rake
 

Gemfile

@@ -10,15 +10,16 @@ group :benchmark, :test do
   gem 'memory_profiler'
   gem 'terminal-table'
 
-  install_if -> { RUBY_PLATFORM !~ /mingw|mswin|java/ } do
+  install_if -> { RUBY_PLATFORM !~ /mingw|mswin|java/ && RUBY_ENGINE != 'truffleruby' } do
     gem 'stackprof'
   end
 end
 
 group :test do
-  gem 'rubocop', '~> 0.53.0'
+  gem 'rubocop', '~> 0.74.0', require: false
+  gem 'rubocop-performance', require: false
 
-  platform :mri do
+  platform :mri, :truffleruby do
     gem 'liquid-c', github: 'Shopify/liquid-c', ref: 'liquid-tag'
   end
 end

Rakefile

@@ -19,8 +19,10 @@ task :warn_test do
 end
 
 task :rubocop do
+  if RUBY_ENGINE == 'ruby'
     require 'rubocop/rake_task'
     RuboCop::RakeTask.new
+  end
 end
 
 desc 'runs test suite with both strict and lax parsers'
@@ -32,8 +34,8 @@ task :test do
   Rake::Task['base_test'].reenable
   Rake::Task['base_test'].invoke
 
-  if RUBY_ENGINE == 'ruby'
+  if RUBY_ENGINE == 'ruby' || RUBY_ENGINE == 'truffleruby'
-    ENV['LIQUID-C'] = '1'
+    ENV['LIQUID_C'] = '1'
 
     ENV['LIQUID_PARSER_MODE'] = 'lax'
     Rake::Task['base_test'].reenable

lib/liquid/tags/echo.rb

@@ -16,7 +16,7 @@ module Liquid
     end
 
     def render(context)
-      @variable.render(context)
+      @variable.render_to_output_buffer(context, '')
     end
   end
 

liquid.gemspec

@@ -16,7 +16,7 @@ Gem::Specification.new do |s|
   s.license     = "MIT"
   # s.description = "A secure, non-evaling end user template engine with aesthetic markup."
 
-  s.required_ruby_version     = ">= 2.1.0"
+  s.required_ruby_version     = ">= 2.4.0"
   s.required_rubygems_version = ">= 1.3.7"
 
   s.test_files  = Dir.glob("{test}/**/*")

performance/memory_profile.rb

@@ -30,6 +30,7 @@ class Profiler
     @retained  << "#{report.scale_bytes(report.total_retained_memsize)} (#{report.total_retained} objects)"
 
     return if ENV['CI']
+
     require 'fileutils'
     report_file = File.join(REPORTS_DIR, "#{sanitize(phase)}.txt")
     FileUtils.mkdir_p(REPORTS_DIR)

test/test_helper.rb

@@ -14,7 +14,7 @@ if env_mode = ENV['LIQUID_PARSER_MODE']
 end
 Liquid::Template.error_mode = mode
 
-if ENV['LIQUID-C'] == '1'
+if ENV['LIQUID_C'] == '1'
   puts "-- LIQUID C"
   require 'liquid/c'
 end