Update readme

Render tag styling fixes

.rubocop.yml

@@ -1,132 +1,16 @@
 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/*'
-    - '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
-
+    - 'vendor/bundle/**/*'
+      
 Naming/MethodName:
   Exclude:
-    - 'example/server/liquid_servlet.rb'
+    - 'example/server/liquid_servlet.rb'

.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.
-# Include: **/*.gemspec
-Gemspec/OrderedDependencies:
+# Configuration parameters: AllowMultipleStyles, EnforcedHashRocketStyle, EnforcedColonStyle, EnforcedLastArgumentHashStyle.
+# SupportedHashRocketStyles: key, separator, table
+# 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
-Metrics/AbcSize:
-  Max: 56
+# Offense count: 95
+# Cop supports --auto-correct.
+# Configuration parameters: AutoCorrect, AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
+# URISchemes: http, https
+Metrics/LineLength:
+  Max: 294
 
-# Offense count: 12
-Metrics/CyclomaticComplexity:
-  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:
+# Offense count: 44
+Naming/ConstantName:
   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.rb'
+    - 'lib/liquid/block_body.rb'
+    - 'lib/liquid/tags/assign.rb'
+    - 'lib/liquid/tags/capture.rb'
+    - 'lib/liquid/tags/case.rb'
+    - 'lib/liquid/tags/cycle.rb'
+    - 'lib/liquid/tags/for.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'
-    - 'test/integration/standard_filter_test.rb'
-    - 'test/integration/tags/for_tag_test.rb'
-    - 'test/integration/template_test.rb'
-    - 'test/unit/condition_unit_test.rb'
+    - 'performance/shopify/comment_form.rb'
+    - 'performance/shopify/paginate.rb'
+    - 'test/integration/tags/include_tag_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
-Style/Alias:
+# SupportedStyles: always, conditionals
+Style/AndOr:
   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'
+    - 'lib/liquid/tags/table_row.rb'
+    - 'lib/liquid/tokenizer.rb'
 
-# Offense count: 22
-Style/CommentedKeyword:
-  Enabled: false
+# Offense count: 40
+# Cop supports --auto-correct.
+# 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
-Style/EmptyMethod:
+# SupportedStyles: each, for
+Style/For:
   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'
+    - 'performance/shopify/shop_filter.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
-Style/FormatStringToken:
+# SupportedStyles: format, sprintf, percent
+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
-# Configuration parameters: MinBodyLength.
-Style/GuardClause:
+# Offense count: 115
+# Cop supports --auto-correct.
+# 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'
-    - 'lib/liquid/lexer.rb'
-    - 'lib/liquid/strainer.rb'
-    - 'lib/liquid/tags/assign.rb'
-    - 'lib/liquid/tags/capture.rb'
-    - 'lib/liquid/tags/case.rb'
+    - 'Gemfile'
+    - 'Rakefile'
+    - 'lib/liquid/block_body.rb'
+    - 'lib/liquid/parser.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'
+    - 'liquid.gemspec'
+    - 'performance/shopify/database.rb'
+    - 'performance/shopify/liquid.rb'
+    - 'test/test_helper.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.
-# 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'
+Style/PerlBackrefs:
+  Enabled: false
 
-# Offense count: 14
+# Offense count: 33
 # 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: compact, exploded
+Style/RaiseArgs:
+  Enabled: false
 
 # 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.
-# SupportedStyles: percent, brackets
-Style/SymbolArray:
-  EnforcedStyle: brackets
+# Configuration parameters: EnforcedStyle.
+# SupportedStyles: use_perl_names, use_english_names
+Style/SpecialGlobalVars:
+  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
+cache: bundler
 
 rvm:
-  - 2.1
-  - 2.2
-  - 2.3
   - 2.4
   - 2.5
   - &latest_ruby 2.6
+  - 2.7
   - ruby-head
   - jruby-head
-#  - rbx-2
-
-addons:
-  apt:
-    packages:
-    - libgmp3-dev
+  - truffleruby
 
 matrix:
   include:
@@ -24,11 +18,13 @@ matrix:
   allow_failures:
     - rvm: ruby-head
     - rvm: jruby-head
+    - rvm: truffleruby
 
-install:
-  - bundle install
-
-script: bundle exec rake
+branches:
+  only:
+    - master
+    - gh-pages
+    - /.*-stable/
 
 notifications:
   disable: true

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
-    gem 'liquid-c', github: 'Shopify/liquid-c', ref: 'liquid-tag'
+  platform :mri, :truffleruby do
+    gem 'liquid-c', github: 'Shopify/liquid-c', ref: 'master'
   end
 end

README.md

@@ -106,3 +106,9 @@ template = Liquid::Template.parse("{{x}} {{y}}")
 template.render!({ 'x' => 1}, { strict_variables: true })
 #=> Liquid::UndefinedVariable: Liquid error: undefined variable y
 ```
+
+### Usage tracking
+
+To help track usages of a feature or code path in production, we have released opt-in usage tracking. To enable this, we provide an empty `Liquid:: Usage.increment` method which you can customize to your needs. The feature is well suited to https://github.com/Shopify/statsd-instrument. However, the choice of implementation is up to you.
+
+Once you have enabled usage tracking, we recommend reporting any events through Github Issues that your system may be logging. It is highly likely this event has been added to consider deprecating or improving code specific to this event, so please raise any concerns.

Rakefile

@@ -19,8 +19,10 @@ task :warn_test do
 end
 
 task :rubocop do
-  require 'rubocop/rake_task'
-  RuboCop::RakeTask.new
+  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'
-    ENV['LIQUID-C'] = '1'
+  if RUBY_ENGINE == 'ruby' || RUBY_ENGINE == 'truffleruby'
+    ENV['LIQUID_C'] = '1'
 
     ENV['LIQUID_PARSER_MODE'] = 'lax'
     Rake::Task['base_test'].reenable

lib/liquid.rb

@@ -74,6 +74,8 @@ require 'liquid/condition'
 require 'liquid/utils'
 require 'liquid/tokenizer'
 require 'liquid/parse_context'
+require 'liquid/partial_cache'
+require 'liquid/usage'
 
 # Load all the tags of the standard library
 #

lib/liquid/context.rb

@@ -12,26 +12,41 @@ module Liquid
   #
   #   context['bob']  #=> nil  class Context
   class Context
-    attr_reader :scopes, :errors, :registers, :environments, :resource_limits
+    attr_reader :scopes, :errors, :registers, :environments, :resource_limits, :static_registers, :static_environments
     attr_accessor :exception_renderer, :template_name, :partial, :global_filter, :strict_variables, :strict_filters
 
-    def initialize(environments = {}, outer_scope = {}, registers = {}, rethrow_errors = false, resource_limits = nil)
-      @environments     = [environments].flatten
-      @scopes           = [(outer_scope || {})]
-      @registers        = registers
-      @errors           = []
-      @interrupts       = []
-      @filters          = []
-      @global_filter    = nil
-      @partial          = false
-      @strict_variables = false
-      @resource_limits  = resource_limits || ResourceLimits.new(Template.default_resource_limits)
+    # rubocop:disable Metrics/ParameterLists
+    def self.build(environments: {}, outer_scope: {}, registers: {}, rethrow_errors: false, resource_limits: nil, static_registers: {}, static_environments: {})
+      new(environments, outer_scope, registers, rethrow_errors, resource_limits, static_registers, static_environments)
+    end
+
+    def initialize(environments = {}, outer_scope = {}, registers = {}, rethrow_errors = false, resource_limits = nil, static_registers = {}, static_environments = {})
+      @environments = [environments]
+      @environments.flatten!
+
+      @static_environments = [static_environments].flat_map(&:freeze).freeze
+      @scopes              = [(outer_scope || {})]
+      @registers           = registers
+      @static_registers    = static_registers.freeze
+      @errors              = []
+      @partial             = false
+      @strict_variables    = false
+      @resource_limits     = resource_limits || ResourceLimits.new(Template.default_resource_limits)
+      @base_scope_depth    = 0
+      squash_instance_assigns_with_environments
+
+      @this_stack_used = false
 
       self.exception_renderer = Template.default_exception_renderer
-      self.exception_renderer = ->(e) { raise } if rethrow_errors
+      if rethrow_errors
+        self.exception_renderer = ->(e) { raise }
+      end
 
-      squash_instance_assigns_with_environments
+      @interrupts = []
+      @filters = []
+      @global_filter = nil
     end
+    # rubocop:enable Metrics/ParameterLists
 
     def warnings
       @warnings ||= []
@@ -83,9 +98,9 @@ module Liquid
     end
 
     # Push new local scope on the stack. use <tt>Context#stack</tt> instead
-    def push
-      @scopes.unshift({})
-      raise StackLevelError, "Nesting too deep".freeze if @scopes.length > (Block::MAX_DEPTH + 1)
+    def push(new_scope = {})
+      @scopes.unshift(new_scope)
+      check_overflow
     end
 
     # Merge a hash of variables in the current local scope
@@ -107,15 +122,50 @@ module Liquid
     #   end
     #
     #   context['var]  #=> nil
-    def stack
-      push
+    def stack(new_scope = nil)
+      old_stack_used = @this_stack_used
+      if new_scope
+        push(new_scope)
+        @this_stack_used = true
+      else
+        @this_stack_used = false
+      end
+
       yield
     ensure
-      pop
+      pop if @this_stack_used
+      @this_stack_used = old_stack_used
+    end
+
+    # Creates a new context inheriting resource limits, filters, environment etc.,
+    # but with an isolated scope.
+    def new_isolated_subcontext
+      check_overflow
+
+      Context.build(
+        resource_limits: resource_limits,
+        static_environments: static_environments,
+        static_registers: static_registers
+      ).tap do |subcontext|
+        subcontext.base_scope_depth = base_scope_depth + 1
+        subcontext.exception_renderer = exception_renderer
+        subcontext.filters = @filters
+        subcontext.strainer = nil
+        subcontext.errors = errors
+        subcontext.warnings = warnings
+      end
+    end
+
+    def clear_instance_assigns
+      @scopes[0] = {}
     end
 
     # Only allow String, Numeric, Hash, Array, Proc, Boolean or <tt>Liquid::Drop</tt>
     def []=(key, value)
+      unless @this_stack_used
+        @this_stack_used = true
+        push({})
+      end
       @scopes[0][key] = value
     end
 
@@ -143,12 +193,15 @@ module Liquid
     def find_variable(key, raise_on_not_found: true)
       # This was changed from find() to find_index() because this is a very hot
       # path and find_index() is optimized in MRI to reduce object allocation
+      index = @scopes.find_index { |s| s.key?(key) }
 
-      scope = (index = @scopes.find_index { |s| s.key?(key)  }) && @scopes[index]
-      scope ||= (index = @environments.find_index { |s| s.key?(key) }) && @environments[index]
-      scope ||= {}
+      variable = if index
+        lookup_and_evaluate(@scopes[index], key, raise_on_not_found: raise_on_not_found)
+      else
+        try_variable_find_in_environments(key, raise_on_not_found: raise_on_not_found)
+      end
 
-      variable = lookup_and_evaluate(scope, key, raise_on_not_found: raise_on_not_found).to_liquid
+      variable = variable.to_liquid
       variable.context = self if variable.respond_to?(:context=)
 
       variable
@@ -168,8 +221,38 @@ module Liquid
       end
     end
 
+    protected
+
+    attr_writer :base_scope_depth, :warnings, :errors, :strainer, :filters
+
     private
 
+    attr_reader :base_scope_depth
+
+    def try_variable_find_in_environments(key, raise_on_not_found:)
+      @environments.each do |environment|
+        found_variable = lookup_and_evaluate(environment, key, raise_on_not_found: raise_on_not_found)
+        if !found_variable.nil? || @strict_variables && raise_on_not_found
+          return found_variable
+        end
+      end
+      @static_environments.each do |environment|
+        found_variable = lookup_and_evaluate(environment, key, raise_on_not_found: raise_on_not_found)
+        if !found_variable.nil? || @strict_variables && raise_on_not_found
+          return found_variable
+        end
+      end
+      nil
+    end
+
+    def check_overflow
+      raise StackLevelError, "Nesting too deep".freeze if overflow?
+    end
+
+    def overflow?
+      base_scope_depth + @scopes.length > Block::MAX_DEPTH
+    end
+
     def internal_error
       # raise and catch to set backtrace and cause on exception
       raise Liquid::InternalError, 'internal'

lib/liquid/locales/en.yml

@@ -22,5 +22,6 @@
       tag_never_closed: "'%{block_name}' tag was never closed"
       meta_syntax_error: "Liquid syntax error: #{e.message}"
       table_row: "Syntax Error in 'table_row loop' - Valid syntax: table_row [item] in [collection] cols=3"
+      render: "Syntax error in tag 'render' - Template name must be a quoted string"
     argument:
       include: "Argument error in tag 'include' - Illegal template name"

lib/liquid/partial_cache.rb

@@ -0,0 +1,18 @@
+module Liquid
+  class PartialCache
+    def self.load(template_name, context:, parse_context:)
+      cached_partials = (context.registers[:cached_partials] ||= {})
+      cached = cached_partials[template_name]
+      return cached if cached
+
+      file_system = (context.registers[:file_system] ||= Liquid::Template.file_system)
+      source = file_system.read_template_file(template_name)
+      parse_context.partial = true
+
+      partial = Liquid::Template.parse(source, parse_context)
+      cached_partials[template_name] = partial
+    ensure
+      parse_context.partial = false
+    end
+  end
+end

lib/liquid/standardfilters.rb

@@ -421,6 +421,7 @@ module Liquid
 
     def default(input, default_value = ''.freeze)
       if !input || input.respond_to?(:empty?) && input.empty?
+        Usage.increment("default_filter_received_false_value") if input == false # See https://github.com/Shopify/liquid/issues/1127
         default_value
       else
         input

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
 

lib/liquid/tags/include.rb

@@ -46,7 +46,12 @@ module Liquid
       template_name = context.evaluate(@template_name_expr)
       raise ArgumentError.new(options[:locale].t("errors.argument.include")) unless template_name
 
-      partial = load_cached_partial(template_name, context)
+      partial = PartialCache.load(
+        template_name,
+        context: context,
+        parse_context: parse_context
+      )
+
       context_variable_name = template_name.split('/'.freeze).last
 
       variable = if @variable_name_expr
@@ -83,35 +88,9 @@ module Liquid
       output
     end
 
-    private
-
     alias_method :parse_context, :options
     private :parse_context
 
-    def load_cached_partial(template_name, context)
-      cached_partials = context.registers[:cached_partials] || {}
-
-      if cached = cached_partials[template_name]
-        return cached
-      end
-      source = read_template_from_file_system(context)
-      begin
-        parse_context.partial = true
-        partial = Liquid::Template.parse(source, parse_context)
-      ensure
-        parse_context.partial = false
-      end
-      cached_partials[template_name] = partial
-      context.registers[:cached_partials] = cached_partials
-      partial
-    end
-
-    def read_template_from_file_system(context)
-      file_system = context.registers[:file_system] || Liquid::Template.file_system
-
-      file_system.read_template_file(context.evaluate(@template_name_expr))
-    end
-
     class ParseTreeVisitor < Liquid::ParseTreeVisitor
       def children
         [

lib/liquid/tags/increment.rb

@@ -23,6 +23,7 @@ module Liquid
     def render_to_output_buffer(context, output)
       value = context.environments.first[@variable] ||= 0
       context.environments.first[@variable] = value + 1
+
       output << value.to_s
       output
     end

lib/liquid/tags/render.rb

@@ -0,0 +1,54 @@
+module Liquid
+  class Render < Tag
+    SYNTAX = /(#{QuotedString})#{QuotedFragment}*/o
+
+    attr_reader :template_name_expr, :attributes
+
+    def initialize(tag_name, markup, options)
+      super
+
+      raise SyntaxError.new(options[:locale].t("errors.syntax.render".freeze)) unless markup =~ SYNTAX
+
+      template_name = $1
+
+      @template_name_expr = Expression.parse(template_name)
+
+      @attributes = {}
+      markup.scan(TagAttributes) do |key, value|
+        @attributes[key] = Expression.parse(value)
+      end
+    end
+
+    def render_to_output_buffer(context, output)
+      # Though we evaluate this here we will only ever parse it as a string literal.
+      template_name = context.evaluate(@template_name_expr)
+      raise ArgumentError.new(options[:locale].t("errors.argument.include")) unless template_name
+
+      partial = PartialCache.load(
+        template_name,
+        context: context,
+        parse_context: parse_context
+      )
+
+      inner_context = context.new_isolated_subcontext
+      inner_context.template_name = template_name
+      inner_context.partial = true
+      @attributes.each do |key, value|
+        inner_context[key] = context.evaluate(value)
+      end
+      partial.render_to_output_buffer(inner_context, output)
+
+      output
+    end
+
+    class ParseTreeVisitor < Liquid::ParseTreeVisitor
+      def children
+        [
+          @node.template_name_expr,
+        ] + @node.attributes.values
+      end
+    end
+  end
+
+  Template.register_tag('render'.freeze, Render)
+end

lib/liquid/usage.rb

@@ -0,0 +1,6 @@
+module Liquid
+  module Usage
+    def self.increment(name)
+    end
+  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/integration/tags/liquid_tag_test.rb

@@ -5,72 +5,72 @@ class LiquidTagTest < Minitest::Test
 
   def test_liquid_tag
     assert_template_result('1 2 3', <<~LIQUID, 'array' => [1, 2, 3])
-    {%- liquid
-      echo array | join: " "
-    -%}
+      {%- liquid
+        echo array | join: " "
+      -%}
     LIQUID
 
     assert_template_result('1 2 3', <<~LIQUID, 'array' => [1, 2, 3])
-    {%- liquid
-      for value in array
-        echo value
-        unless forloop.last
-          echo " "
-        endunless
-      endfor
-    -%}
+      {%- liquid
+        for value in array
+          echo value
+          unless forloop.last
+            echo " "
+          endunless
+        endfor
+      -%}
     LIQUID
 
     assert_template_result('4 8 12 6', <<~LIQUID, 'array' => [1, 2, 3])
-    {%- liquid
-      for value in array
-        assign double_value = value | times: 2
-        echo double_value | times: 2
-        unless forloop.last
-          echo " "
-        endunless
-      endfor
+      {%- liquid
+        for value in array
+          assign double_value = value | times: 2
+          echo double_value | times: 2
+          unless forloop.last
+            echo " "
+          endunless
+        endfor
 
-      echo " "
-      echo double_value
-    -%}
+        echo " "
+        echo double_value
+      -%}
     LIQUID
 
     assert_template_result('abc', <<~LIQUID)
-    {%- liquid echo "a" -%}
-    b
-    {%- liquid echo "c" -%}
+      {%- liquid echo "a" -%}
+      b
+      {%- liquid echo "c" -%}
     LIQUID
   end
 
   def test_liquid_tag_errors
     assert_match_syntax_error("syntax error (line 1): Unknown tag 'error'", <<~LIQUID)
-    {%- liquid error no such tag -%}
+      {%- liquid error no such tag -%}
     LIQUID
 
     assert_match_syntax_error("syntax error (line 7): Unknown tag 'error'", <<~LIQUID)
-    {{ test }}
+      {{ test }}
 
-    {%-
-    liquid
-      for value in array
+      {%-
+      liquid
+        for value in array
 
-        error no such tag
-      endfor
-    -%}
+          error no such tag
+        endfor
+      -%}
     LIQUID
 
     assert_match_syntax_error("syntax error (line 2): Unknown tag '!!! the guards are vigilant'", <<~LIQUID)
-    {%- liquid
-      !!! the guards are vigilant
-    -%}
+      {%- liquid
+        !!! the guards are vigilant
+      -%}
     LIQUID
 
     assert_match_syntax_error("syntax error (line 4): 'for' tag was never closed", <<~LIQUID)
-    {%- liquid
-      for value in array
-        echo 'forgot to close the for tag'
-    -%}
+      {%- liquid
+        for value in array
+          echo 'forgot to close the for tag'
+      -%}
     LIQUID
   end
 
@@ -81,24 +81,24 @@ class LiquidTagTest < Minitest::Test
 
   def test_cannot_open_blocks_living_past_a_liquid_tag
     assert_match_syntax_error("syntax error (line 3): 'if' tag was never closed", <<~LIQUID)
-    {%- liquid
-      if true
-    -%}
-    {%- endif -%}
+      {%- liquid
+        if true
+      -%}
+      {%- endif -%}
     LIQUID
   end
 
   def test_quirk_can_close_blocks_created_before_a_liquid_tag
     assert_template_result("42", <<~LIQUID)
-    {%- if true -%}
-    42
-    {%- liquid endif -%}
+      {%- if true -%}
+      42
+      {%- liquid endif -%}
     LIQUID
   end
 
   def test_liquid_tag_in_raw
     assert_template_result("{% liquid echo 'test' %}\n", <<~LIQUID)
-    {% raw %}{% liquid echo 'test' %}{% endraw %}
+      {% raw %}{% liquid echo 'test' %}{% endraw %}
     LIQUID
   end
 end

test/integration/tags/render_tag_test.rb

@@ -0,0 +1,149 @@
+require 'test_helper'
+
+class RenderTagTest < Minitest::Test
+  include Liquid
+
+  def test_render_with_no_arguments
+    Liquid::Template.file_system = StubFileSystem.new('source' => 'rendered content')
+    assert_template_result 'rendered content', '{% render "source" %}'
+  end
+
+  def test_render_tag_looks_for_file_system_in_registers_first
+    file_system = StubFileSystem.new('pick_a_source' => 'from register file system')
+    assert_equal 'from register file system',
+      Template.parse('{% render "pick_a_source" %}').render!({}, registers: { file_system: file_system })
+  end
+
+  def test_render_passes_named_arguments_into_inner_scope
+    Liquid::Template.file_system = StubFileSystem.new('product' => '{{ inner_product.title }}')
+    assert_template_result 'My Product', '{% render "product", inner_product: outer_product %}',
+      'outer_product' => { 'title' => 'My Product' }
+  end
+
+  def test_render_accepts_literals_as_arguments
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ price }}')
+    assert_template_result '123', '{% render "snippet", price: 123 %}'
+  end
+
+  def test_render_accepts_multiple_named_arguments
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ one }} {{ two }}')
+    assert_template_result '1 2', '{% render "snippet", one: 1, two: 2 %}'
+  end
+
+  def test_render_does_not_inherit_parent_scope_variables
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ outer_variable }}')
+    assert_template_result '', '{% assign outer_variable = "should not be visible" %}{% render "snippet" %}'
+  end
+
+  def test_render_does_not_inherit_variable_with_same_name_as_snippet
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ snippet }}')
+    assert_template_result '', "{% assign snippet = 'should not be visible' %}{% render 'snippet' %}"
+  end
+
+  def test_render_sets_the_correct_template_name_for_errors
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ unsafe }}')
+
+    with_taint_mode :error do
+      template = Liquid::Template.parse('{% render "snippet", unsafe: unsafe %}')
+      context = Context.new('unsafe' => (+'unsafe').tap(&:taint))
+      template.render(context)
+
+      assert_equal [Liquid::TaintedError], template.errors.map(&:class)
+      assert_equal 'snippet', template.errors.first.template_name
+    end
+  end
+
+  def test_render_sets_the_correct_template_name_for_warnings
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ unsafe }}')
+
+    with_taint_mode :warn do
+      template = Liquid::Template.parse('{% render "snippet", unsafe: unsafe %}')
+      context = Context.new('unsafe' => (+'unsafe').tap(&:taint))
+      template.render(context)
+
+      assert_equal [Liquid::TaintedError], context.warnings.map(&:class)
+      assert_equal 'snippet', context.warnings.first.template_name
+    end
+  end
+
+  def test_render_does_not_mutate_parent_scope
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{% assign inner = 1 %}')
+    assert_template_result '', "{% render 'snippet' %}{{ inner }}"
+  end
+
+  def test_nested_render_tag
+    Liquid::Template.file_system = StubFileSystem.new(
+      'one' => "one {% render 'two' %}",
+      'two' => 'two'
+    )
+    assert_template_result 'one two', "{% render 'one' %}"
+  end
+
+  def test_recursively_rendered_template_does_not_produce_endless_loop
+    Liquid::Template.file_system = StubFileSystem.new('loop' => '{% render "loop" %}')
+
+    assert_raises Liquid::StackLevelError do
+      Template.parse('{% render "loop" %}').render!
+    end
+  end
+
+  def test_includes_and_renders_count_towards_the_same_recursion_limit
+    Liquid::Template.file_system = StubFileSystem.new(
+      'loop_render' => '{% render "loop_include" %}',
+      'loop_include' => '{% include "loop_render" %}'
+    )
+
+    assert_raises Liquid::StackLevelError  do
+      Template.parse('{% render "loop_include" %}').render!
+    end
+  end
+
+  def test_dynamically_choosen_templates_are_not_allowed
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => 'should not be rendered')
+
+    assert_raises Liquid::SyntaxError do
+      Liquid::Template.parse("{% assign name = 'snippet' %}{% render name %}")
+    end
+  end
+
+  def test_include_tag_caches_second_read_of_same_partial
+    file_system = StubFileSystem.new('snippet' => 'echo')
+    assert_equal 'echoecho',
+      Template.parse('{% render "snippet" %}{% render "snippet" %}')
+      .render!({}, registers: { file_system: file_system })
+    assert_equal 1, file_system.file_read_count
+  end
+
+  def test_render_tag_doesnt_cache_partials_across_renders
+    file_system = StubFileSystem.new('snippet' => 'my message')
+
+    assert_equal 'my message',
+      Template.parse('{% include "snippet" %}').render!({}, registers: { file_system: file_system })
+    assert_equal 1, file_system.file_read_count
+
+    assert_equal 'my message',
+      Template.parse('{% include "snippet" %}').render!({}, registers: { file_system: file_system })
+    assert_equal 2, file_system.file_read_count
+  end
+
+  def test_render_tag_within_if_statement
+    Liquid::Template.file_system = StubFileSystem.new('snippet' => 'my message')
+    assert_template_result 'my message', '{% if true %}{% render "snippet" %}{% endif %}'
+  end
+
+  def test_break_through_render
+    Liquid::Template.file_system = StubFileSystem.new('break' => '{% break %}')
+    assert_template_result '1', '{% for i in (1..3) %}{{ i }}{% break %}{{ i }}{% endfor %}'
+    assert_template_result '112233', '{% for i in (1..3) %}{{ i }}{% render "break" %}{{ i }}{% endfor %}'
+  end
+
+  def test_increment_is_isolated_between_renders
+    Liquid::Template.file_system = StubFileSystem.new('incr' => '{% increment %}')
+    assert_template_result '010', '{% increment %}{% increment %}{% render "incr" %}'
+  end
+
+  def test_decrement_is_isolated_between_renders
+    Liquid::Template.file_system = StubFileSystem.new('decr' => '{% decrement %}')
+    assert_template_result '-1-2-1', '{% decrement %}{% decrement %}{% render "decr" %}'
+  end
+end

test/integration/variable_test.rb

@@ -80,7 +80,10 @@ class VariableTest < Minitest::Test
     assigns['test'] = 'Tobi'
     assert_equal 'Hello Tobi', template.render!(assigns)
     assigns.delete('test')
-    assert_equal "Hello ", template.render!(assigns)
+    e = assert_raises(RuntimeError) do
+      template.render!(assigns)
+    end
+    assert_equal "Unknown variable 'test'", e.message
   end
 
   def test_multiline_variable

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
@@ -121,3 +121,17 @@ class ErrorDrop < Liquid::Drop
     raise Exception, 'exception'
   end
 end
+
+class StubFileSystem
+  attr_reader :file_read_count
+
+  def initialize(values)
+    @file_read_count = 0
+    @values = values
+  end
+
+  def read_template_file(template_path)
+    @file_read_count += 1
+    @values.fetch(template_path)
+  end
+end

test/unit/context_unit_test.rb

@@ -468,11 +468,79 @@ class ContextUnitTest < Minitest::Test
     assert_equal 'hi filtered', context.apply_global_filter('hi')
   end
 
+  def test_static_environments_are_read_with_lower_priority_than_environments
+    context = Context.build(
+      static_environments: { 'shadowed' => 'static', 'unshadowed' => 'static' },
+      environments: { 'shadowed' => 'dynamic' }
+    )
+
+    assert_equal 'dynamic', context['shadowed']
+    assert_equal 'static', context['unshadowed']
+  end
+
   def test_apply_global_filter_when_no_global_filter_exist
     context = Context.new
     assert_equal 'hi', context.apply_global_filter('hi')
   end
 
+  def test_new_isolated_subcontext_does_not_inherit_variables
+    super_context = Context.new
+    super_context['my_variable'] = 'some value'
+    subcontext = super_context.new_isolated_subcontext
+
+    assert_nil subcontext['my_variable']
+  end
+
+  def test_new_isolated_subcontext_inherits_static_environment
+    super_context = Context.build(static_environments: { 'my_environment_value' => 'my value' })
+    subcontext = super_context.new_isolated_subcontext
+
+    assert_equal 'my value', subcontext['my_environment_value']
+  end
+
+  def test_new_isolated_subcontext_inherits_resource_limits
+    resource_limits = ResourceLimits.new({})
+    super_context = Context.new({}, {}, {}, false, resource_limits)
+    subcontext = super_context.new_isolated_subcontext
+    assert_equal resource_limits, subcontext.resource_limits
+  end
+
+  def test_new_isolated_subcontext_inherits_exception_renderer
+    super_context = Context.new
+    super_context.exception_renderer = ->(_e) { 'my exception message' }
+    subcontext = super_context.new_isolated_subcontext
+    assert_equal 'my exception message', subcontext.handle_error(Liquid::Error.new)
+  end
+
+  def test_new_isolated_subcontext_does_not_inherit_non_static_registers
+    registers = {
+      my_register: :my_value
+    }
+    super_context = Context.new({}, {}, registers)
+    subcontext = super_context.new_isolated_subcontext
+    assert_nil subcontext.registers[:my_register]
+  end
+
+  def test_new_isolated_subcontext_inherits_static_registers
+    super_context = Context.build(static_registers: { my_register: :my_value })
+    subcontext = super_context.new_isolated_subcontext
+    assert_equal :my_value, subcontext.static_registers[:my_register]
+  end
+
+  def test_new_isolated_subcontext_inherits_filters
+    my_filter = Module.new do
+      def my_filter(*)
+        'my filter result'
+      end
+    end
+
+    super_context = Context.new
+    super_context.add_filters([my_filter])
+    subcontext = super_context.new_isolated_subcontext
+    template = Template.parse('{{ 123 | my_filter }}')
+    assert_equal 'my filter result', template.render(subcontext)
+  end
+
   private
 
   def assert_no_object_allocations

test/unit/partial_cache_unit_test.rb

@@ -0,0 +1,91 @@
+require 'test_helper'
+
+class PartialCacheUnitTest < Minitest::Test
+  def test_uses_the_file_system_register_if_present
+    context = Liquid::Context.build(
+      registers: {
+        file_system: StubFileSystem.new('my_partial' => 'my partial body'),
+      }
+    )
+
+    partial = Liquid::PartialCache.load(
+      'my_partial',
+      context: context,
+      parse_context: Liquid::ParseContext.new
+    )
+
+    assert_equal 'my partial body', partial.render
+  end
+
+  def test_reads_from_the_file_system_only_once_per_file
+    file_system = StubFileSystem.new('my_partial' => 'some partial body')
+    context = Liquid::Context.build(
+      registers: { file_system: file_system }
+    )
+
+    2.times do
+      Liquid::PartialCache.load(
+        'my_partial',
+        context: context,
+        parse_context: Liquid::ParseContext.new
+      )
+    end
+
+    assert_equal 1, file_system.file_read_count
+  end
+
+  def test_cache_state_is_stored_per_context
+    parse_context = Liquid::ParseContext.new
+    shared_file_system = StubFileSystem.new(
+      'my_partial' => 'my shared value'
+    )
+    context_one = Liquid::Context.build(
+      registers: {
+        file_system: shared_file_system,
+      }
+    )
+    context_two = Liquid::Context.build(
+      registers: {
+        file_system: shared_file_system,
+      }
+    )
+
+    2.times do
+      Liquid::PartialCache.load(
+        'my_partial',
+        context: context_one,
+        parse_context: parse_context
+      )
+    end
+
+    Liquid::PartialCache.load(
+      'my_partial',
+      context: context_two,
+      parse_context: parse_context
+    )
+
+    assert_equal 2, shared_file_system.file_read_count
+  end
+
+  def test_cache_is_not_broken_when_a_different_parse_context_is_used
+    file_system = StubFileSystem.new('my_partial' => 'some partial body')
+    context = Liquid::Context.build(
+      registers: { file_system: file_system }
+    )
+
+    Liquid::PartialCache.load(
+      'my_partial',
+      context: context,
+      parse_context: Liquid::ParseContext.new(my_key: 'value one')
+    )
+    Liquid::PartialCache.load(
+      'my_partial',
+      context: context,
+      parse_context: Liquid::ParseContext.new(my_key: 'value two')
+    )
+
+    # Technically what we care about is that the file was parsed twice,
+    # but measuring file reads is an OK proxy for this.
+    assert_equal 1, file_system.file_read_count
+  end
+end