Merge pull request #1601 from Shopify/bump/5.4.0

Bump version to 5.4.0 for release

.github/workflows/liquid.yml

@@ -6,13 +6,12 @@ jobs:
     strategy:
       matrix:
         entry:
-          - { ruby: 2.5, allowed-failure: false }
-          - { ruby: 2.6, allowed-failure: false }
-          - { ruby: 2.7, allowed-failure: false }
+          - { ruby: 2.7, allowed-failure: false } # minimum supported
+          - { ruby: 3.1, allowed-failure: false } # latest
           - { ruby: ruby-head, allowed-failure: true }
     name: test (${{ matrix.entry.ruby }})
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.entry.ruby }}
@@ -27,7 +26,7 @@ jobs:
   memory_profile:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.7

.rubocop.yml

@@ -1,5 +1,7 @@
+inherit_gem:
+  rubocop-shopify: rubocop.yml
+
 inherit_from:
-  - 'https://shopify.github.io/ruby-style-guide/rubocop.yml'
   - .rubocop_todo.yml
 
 require: rubocop-performance
@@ -8,7 +10,7 @@ Performance:
   Enabled: true
 
 AllCops:
-  TargetRubyVersion: 2.4
+  TargetRubyVersion: 2.7
   NewCops: disable
   Exclude:
     - 'vendor/bundle/**/*'
@@ -16,3 +18,7 @@ AllCops:
 Naming/MethodName:
   Exclude:
     - 'example/server/liquid_servlet.rb'
+
+# Backport https://github.com/Shopify/ruby-style-guide/pull/258
+Layout/BeginEndAlignment:
+  Enabled: true

.rubocop_todo.yml

@@ -1,27 +1,74 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2020-12-11 18:53:41 UTC using RuboCop version 1.6.1.
+# on 2022-05-18 19:25:47 UTC using RuboCop version 1.29.1.
 # 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: 2
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: runtime_error, standard_error
-Lint/InheritException:
+# Offense count: 1
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: TreatCommentsAsGroupSeparators, ConsiderPunctuation, Include.
+# Include: **/*.gemspec
+Gemspec/OrderedDependencies:
   Exclude:
-    - 'lib/liquid/interrupts.rb'
+    - 'liquid.gemspec'
 
-# Offense count: 113
-# Cop supports --auto-correct.
-# Configuration parameters: AutoCorrect, AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.
-# URISchemes: http, https
-Layout/LineLength:
-  Max: 260
+# Offense count: 6
+# This cop supports safe auto-correction (--auto-correct).
+Layout/ClosingHeredocIndentation:
+  Exclude:
+    - 'test/integration/tags/for_tag_test.rb'
+
+# Offense count: 34
+# This cop supports safe auto-correction (--auto-correct).
+Layout/EmptyLineAfterGuardClause:
+  Exclude:
+    - 'lib/liquid/block.rb'
+    - 'lib/liquid/block_body.rb'
+    - 'lib/liquid/context.rb'
+    - 'lib/liquid/drop.rb'
+    - 'lib/liquid/lexer.rb'
+    - 'lib/liquid/parser.rb'
+    - 'lib/liquid/profiler/hooks.rb'
+    - 'lib/liquid/standardfilters.rb'
+    - 'lib/liquid/tags/for.rb'
+    - 'lib/liquid/tags/if.rb'
+    - 'lib/liquid/utils.rb'
+    - 'lib/liquid/variable.rb'
+    - 'lib/liquid/variable_lookup.rb'
+    - 'performance/shopify/money_filter.rb'
+    - 'performance/shopify/paginate.rb'
 
 # Offense count: 8
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: AllowAliasSyntax, AllowedMethods.
+# AllowedMethods: alias_method, public, protected, private
+Layout/EmptyLinesAroundAttributeAccessor:
+  Exclude:
+    - 'lib/liquid/template.rb'
+    - 'test/integration/filter_test.rb'
+    - 'test/integration/tags/include_tag_test.rb'
+    - 'test/unit/strainer_template_unit_test.rb'
+
+# Offense count: 17
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle, IndentationWidth.
+# SupportedStyles: aligned, indented
+Layout/LineEndStringConcatenationIndentation:
+  Exclude:
+    - 'test/integration/tags/for_tag_test.rb'
+    - 'test/integration/tags/increment_tag_test.rb'
+
+# Offense count: 1
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle, IndentationWidth.
+# SupportedStyles: aligned, indented
+Layout/MultilineOperationIndentation:
+  Exclude:
+    - 'lib/liquid/expression.rb'
+
+# Offense count: 9
 Lint/MissingSuper:
   Exclude:
     - 'lib/liquid/forloop_drop.rb'
@@ -33,7 +80,7 @@ Lint/MissingSuper:
     - 'test/integration/tags/for_tag_test.rb'
     - 'test/integration/tags/table_row_test.rb'
 
-# Offense count: 43
+# Offense count: 44
 Naming/ConstantName:
   Exclude:
     - 'lib/liquid.rb'
@@ -51,7 +98,83 @@ Naming/ConstantName:
     - 'performance/shopify/paginate.rb'
     - 'test/integration/tags/include_tag_test.rb'
 
+# Offense count: 9
+# Configuration parameters: CheckIdentifiers, CheckConstants, CheckVariables, CheckStrings, CheckSymbols, CheckComments, CheckFilepaths, FlaggedTerms.
+Naming/InclusiveLanguage:
+  Exclude:
+    - 'lib/liquid/drop.rb'
+    - 'lib/liquid/parse_context.rb'
+    - 'test/integration/drop_test.rb'
+    - 'test/integration/tags/if_else_tag_test.rb'
+
 # Offense count: 2
 Style/ClassVars:
   Exclude:
     - 'lib/liquid/condition.rb'
+
+# Offense count: 3
+# This cop supports safe auto-correction (--auto-correct).
+Style/ExplicitBlockArgument:
+  Exclude:
+    - 'test/integration/context_test.rb'
+    - 'test/integration/tag/disableable_test.rb'
+    - 'test/integration/tags/for_tag_test.rb'
+
+# Offense count: 2982
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle, ConsistentQuotesInMultiline.
+# SupportedStyles: single_quotes, double_quotes
+Style/StringLiterals:
+  Enabled: false
+
+# Offense count: 20
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle.
+# SupportedStyles: single_quotes, double_quotes
+Style/StringLiteralsInInterpolation:
+  Exclude:
+    - 'lib/liquid/condition.rb'
+    - 'lib/liquid/strainer_template.rb'
+    - 'lib/liquid/tag/disableable.rb'
+    - 'performance/shopify/shop_filter.rb'
+    - 'performance/shopify/tag_filter.rb'
+
+# Offense count: 6
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyleForMultiline.
+# SupportedStylesForMultiline: comma, consistent_comma, no_comma
+Style/TrailingCommaInArrayLiteral:
+  Exclude:
+    - 'example/server/example_servlet.rb'
+    - 'lib/liquid/condition.rb'
+    - 'test/integration/context_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+    - 'test/unit/parse_tree_visitor_test.rb'
+
+# Offense count: 1
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyleForMultiline.
+# SupportedStylesForMultiline: comma, consistent_comma, no_comma
+Style/TrailingCommaInHashLiteral:
+  Exclude:
+    - 'lib/liquid/expression.rb'
+
+# Offense count: 19
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: EnforcedStyle, MinSize, WordRegex.
+# SupportedStyles: percent, brackets
+Style/WordArray:
+  Exclude:
+    - 'lib/liquid/tags/if.rb'
+    - 'liquid.gemspec'
+    - 'test/integration/assign_test.rb'
+    - 'test/integration/context_test.rb'
+    - 'test/integration/drop_test.rb'
+    - 'test/integration/standard_filter_test.rb'
+
+# Offense count: 117
+# This cop supports safe auto-correction (--auto-correct).
+# Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, AllowedPatterns, IgnoredPatterns.
+# URISchemes: http, https
+Layout/LineLength:
+  Max: 260

CONTRIBUTING.md

@@ -5,6 +5,7 @@
 * Bugfixes
 * Performance improvements
 * Features that are likely to be useful to the majority of Liquid users
+* Documentation updates that are concise and likely to be useful to the majority of Liquid users
 
 ## Things we won't merge
 
@@ -14,12 +15,14 @@
 * Features that can easily be implemented on top of Liquid (for example as a custom filter or custom filesystem)
 * Code that does not include tests
 * Code that breaks existing tests
+* Documentation changes that are verbose, incorrect or not important to most people (we want to keep it simple and easy to understand)
 
 ## Workflow
 
+* [Sign the CLA](https://cla.shopify.com/) if you haven't already
 * Fork the Liquid repository
 * Create a new branch in your fork
+  * For updating [Liquid documentation](https://shopify.github.io/liquid/), create it from `gh-pages` branch. (You can skip tests.)
 * If it makes sense, add tests for your code and/or run a performance benchmark
 * Make sure all tests pass (`bundle exec rake`)
 * Create a pull request
-

Gemfile

@@ -18,7 +18,7 @@ group :benchmark, :test do
 end
 
 group :test do
-  gem 'rubocop', '~> 1.4', require: false
+  gem 'rubocop-shopify', '~> 2.7.0', require: false
   gem 'rubocop-performance', require: false
 
   platform :mri, :truffleruby do

History.md

@@ -1,5 +1,61 @@
 # Liquid Change Log
 
+## 5.4.0 2022-07-29
+
+### Breaking Changes
+* Drop support for end-of-life Ruby versions (2.5 and 2.6) (#1578) [Andy Waite]
+
+### Features
+* Allow `#` to be used as an inline comment tag (#1498) [CP Clermont]
+
+### Fixes
+* `PartialCache` now shares snippet cache with subcontexts by default (#1553) [Chris AtLee]
+* Hash registers no longer leak into subcontexts as static registers (#1564) [Chris AtLee]
+* Fix `ParseTreeVisitor` for `with` variable expressions in `Render` tag (#1596) [CP Clermont]
+
+### Changed
+* Liquid::Context#registers now always returns a Liquid::Registers object, though supports the most used Hash functions for compatibility (#1553)
+
+## 5.3.0 2022-03-22
+
+### Fixes
+* StandardFilter: Fix missing @context on iterations (#1525) [Thierry Joyal]
+* Fix warning about block and default value in `static_registers.rb` (#1531) [Peter Zhu]
+
+### Deprecation
+* Condition#evaluate to require mandatory context argument in Liquid 6.0.0 (#1527) [Thierry Joyal]
+
+## 5.2.0 2022-03-01
+
+### Features
+* Add `remove_last`, and `replace_last` filters (#1422) [Anders Hagbard]
+* Eagerly cache global filters (#1524) [Jean Boussier]
+
+### Fixes
+* Fix some internal errors in filters from invalid input (#1476) [Dylan Thacker-Smith]
+* Allow dash in filter kwarg name for consistency with Liquid::C (#1518) [CP Clermont]
+
+## 5.1.0 / 2021-09-09
+
+### Features
+* Add `base64_encode`, `base64_decode`, `base64_url_safe_encode`, and `base64_url_safe_decode` filters (#1450) [Daniel Insley]
+* Introduce `to_liquid_value` in `Liquid::Drop` (#1441) [Michael Go]
+
+### Fixes
+* Fix support for using a String subclass for the liquid source (#1421) [Dylan Thacker-Smith]
+* Add `ParseTreeVisitor` to `RangeLookup` (#1470) [CP Clermont]
+* Translate `RangeError` to `Liquid::Error` for `truncatewords` with large int (#1431) [Dylan Thacker-Smith]
+
+## 5.0.1 / 2021-03-24
+
+### Fixes
+* Add ParseTreeVisitor to Echo tag (#1414) [CP Clermont]
+* Test with ruby 3.0 as the latest ruby version (#1398) [Dylan Thacker-Smith]
+* Handle carriage return in newlines_to_br (#1391) [Unending]
+
+### Performance Improvements
+* Use split limit in truncatewords (#1361) [Dylan Thacker-Smith]
+
 ## 5.0.0 / 2021-01-06
 
 ### Features

README.md

@@ -5,7 +5,7 @@
 
 * [Contributing guidelines](CONTRIBUTING.md)
 * [Version history](History.md)
-* [Liquid documentation from Shopify](http://docs.shopify.com/themes/liquid-basics)
+* [Liquid documentation from Shopify](https://shopify.dev/api/liquid)
 * [Liquid Wiki at GitHub](https://github.com/Shopify/liquid/wiki)
 * [Website](http://liquidmarkup.org/)
 
@@ -56,20 +56,20 @@ For standard use you can just pass it the content of a file and call render with
 
 Setting the error mode of Liquid lets you specify how strictly you want your templates to be interpreted.
 Normally the parser is very lax and will accept almost anything without error. Unfortunately this can make
-it very hard to debug and can lead to unexpected behaviour. 
+it very hard to debug and can lead to unexpected behaviour.
 
 Liquid also comes with a stricter parser that can be used when editing templates to give better error messages
 when templates are invalid. You can enable this new parser like this:
 
 ```ruby
 Liquid::Template.error_mode = :strict # Raises a SyntaxError when invalid syntax is used
-Liquid::Template.error_mode = :warn # Adds errors to template.errors but continues as normal
+Liquid::Template.error_mode = :warn # Adds strict errors to template.errors but continues as normal
 Liquid::Template.error_mode = :lax # The default mode, accepts almost anything.
 ```
 
 If you want to set the error mode only on specific templates you can pass `:error_mode` as an option to `parse`:
 ```ruby
-Liquid::Template.parse(source, :error_mode => :strict)
+Liquid::Template.parse(source, error_mode: :strict)
 ```
 This is useful for doing things like enabling strict mode only in the theme editor.
 

lib/liquid.rb

@@ -29,6 +29,7 @@ module Liquid
   WhitespaceControl           = '-'
   TagStart                    = /\{\%/
   TagEnd                      = /\%\}/
+  TagName                     = /#|\w+/
   VariableSignature           = /\(?[\w\-\.\[\]]\)?/
   VariableSegment             = /[\w\-]/
   VariableStart               = /\{\{/
@@ -36,7 +37,7 @@ module Liquid
   VariableIncompleteEnd       = /\}\}?/
   QuotedString                = /"[^"]*"|'[^']*'/
   QuotedFragment              = /#{QuotedString}|(?:[^\s,\|'"]|#{QuotedString})+/o
-  TagAttributes               = /(\w+)\s*\:\s*(#{QuotedFragment})/o
+  TagAttributes               = /(\w[\w-]*)\s*\:\s*(#{QuotedFragment})/o
   AnyStartingTag              = /#{TagStart}|#{VariableStart}/o
   PartialTemplateParser       = /#{TagStart}.*?#{TagEnd}|#{VariableStart}.*?#{VariableIncompleteEnd}/om
   TemplateParser              = /(#{PartialTemplateParser}|#{AnyStartingTag})/om
@@ -59,8 +60,8 @@ require 'liquid/forloop_drop'
 require 'liquid/extensions'
 require 'liquid/errors'
 require 'liquid/interrupts'
-require 'liquid/strainer_factory'
 require 'liquid/strainer_template'
+require 'liquid/strainer_factory'
 require 'liquid/expression'
 require 'liquid/context'
 require 'liquid/parser_switching'
@@ -83,8 +84,7 @@ require 'liquid/tokenizer'
 require 'liquid/parse_context'
 require 'liquid/partial_cache'
 require 'liquid/usage'
-require 'liquid/register'
-require 'liquid/static_registers'
+require 'liquid/registers'
 require 'liquid/template_factory'
 
 # Load all the tags of the standard library

lib/liquid/block_body.rb

@@ -4,8 +4,8 @@ require 'English'
 
 module Liquid
   class BlockBody
-    LiquidTagToken      = /\A\s*([\w#]+)\s*(.*?)\z/o
-    FullToken           = /\A#{TagStart}#{WhitespaceControl}?(\s*)(\w+)(\s*)(.*?)#{WhitespaceControl}?#{TagEnd}\z/om
+    LiquidTagToken      = /\A\s*(#{TagName})\s*(.*?)\z/o
+    FullToken           = /\A#{TagStart}#{WhitespaceControl}?(\s*)(#{TagName})(\s*)(.*?)#{WhitespaceControl}?#{TagEnd}\z/om
     ContentOfVariable   = /\A#{VariableStart}#{WhitespaceControl}?(.*?)#{WhitespaceControl}?#{VariableEnd}\z/om
     WhitespaceOrNothing = /\A\s*\z/
     TAGSTART            = "{%"
@@ -37,7 +37,7 @@ module Liquid
 
     private def parse_for_liquid_tag(tokenizer, parse_context)
       while (token = tokenizer.shift)
-        unless token.empty? || token =~ WhitespaceOrNothing
+        unless token.empty? || token.match?(WhitespaceOrNothing)
           unless token =~ LiquidTagToken
             # line isn't empty but didn't match tag syntax, yield and let the
             # caller raise a syntax error
@@ -150,7 +150,7 @@ module Liquid
           end
           parse_context.trim_whitespace = false
           @nodelist << token
-          @blank &&= !!(token =~ WhitespaceOrNothing)
+          @blank &&= token.match?(WhitespaceOrNothing)
         end
         parse_context.line_number = tokenizer.line_number
       end
@@ -231,8 +231,8 @@ module Liquid
     end
 
     def create_variable(token, parse_context)
-      token.scan(ContentOfVariable) do |content|
-        markup = content.first
+      if token =~ ContentOfVariable
+        markup = Regexp.last_match(1)
         return Variable.new(markup, parse_context)
       end
       BlockBody.raise_missing_variable_terminator(token, parse_context)

lib/liquid/condition.rb

@@ -8,7 +8,7 @@ module Liquid
   #   c = Condition.new(1, '==', 1)
   #   c.evaluate #=> true
   #
-  class Condition #:nodoc:
+  class Condition # :nodoc:
     @@operators = {
       '==' => ->(cond, left, right) {  cond.send(:equal_variables, left, right) },
       '!=' => ->(cond, left, right) { !cond.send(:equal_variables, left, right) },
@@ -61,7 +61,7 @@ module Liquid
       @child_condition = nil
     end
 
-    def evaluate(context = Context.new)
+    def evaluate(context = deprecated_default_context)
       condition = self
       result = nil
       loop do
@@ -134,8 +134,8 @@ module Liquid
       # return this as the result.
       return context.evaluate(left) if op.nil?
 
-      left  = context.evaluate(left)
-      right = context.evaluate(right)
+      left  = Liquid::Utils.to_liquid_value(context.evaluate(left))
+      right = Liquid::Utils.to_liquid_value(context.evaluate(right))
 
       operation = self.class.operators[op] || raise(Liquid::ArgumentError, "Unknown operator #{op}")
 
@@ -150,6 +150,12 @@ module Liquid
       end
     end
 
+    def deprecated_default_context
+      warn("DEPRECATION WARNING: Condition#evaluate without a context argument is deprecated" \
+        " and will be removed from Liquid 6.0.0.")
+      Context.new
+    end
+
     class ParseTreeVisitor < Liquid::ParseTreeVisitor
       def children
         [

lib/liquid/context.rb

@@ -28,7 +28,7 @@ module Liquid
 
       @static_environments = [static_environments].flat_map(&:freeze).freeze
       @scopes              = [(outer_scope || {})]
-      @registers           = registers
+      @registers           = registers.is_a?(Registers) ? registers : Registers.new(registers)
       @errors              = []
       @partial             = false
       @strict_variables    = false
@@ -39,6 +39,10 @@ module Liquid
       @global_filter       = nil
       @disabled_tags       = {}
 
+      @registers.static[:cached_partials] ||= {}
+      @registers.static[:file_system] ||= Liquid::Template.file_system
+      @registers.static[:template_factory] ||= Liquid::TemplateFactory.new
+
       self.exception_renderer = Template.default_exception_renderer
       if rethrow_errors
         self.exception_renderer = Liquid::RAISE_EXCEPTION_LAMBDA
@@ -124,7 +128,7 @@ module Liquid
     #      context['var'] = 'hi'
     #   end
     #
-    #   context['var]  #=> nil
+    #   context['var']  #=> nil
     def stack(new_scope = {})
       push(new_scope)
       yield
@@ -140,7 +144,7 @@ module Liquid
       self.class.build(
         resource_limits: resource_limits,
         static_environments: static_environments,
-        registers: StaticRegisters.new(registers)
+        registers: Registers.new(registers)
       ).tap do |subcontext|
         subcontext.base_scope_depth   = base_scope_depth + 1
         subcontext.exception_renderer = exception_renderer

lib/liquid/expression.rb

@@ -10,21 +10,23 @@ module Liquid
       'empty' => ''
     }.freeze
 
-    SINGLE_QUOTED_STRING = /\A\s*'(.*)'\s*\z/m
-    DOUBLE_QUOTED_STRING = /\A\s*"(.*)"\s*\z/m
-    INTEGERS_REGEX       = /\A\s*(-?\d+)\s*\z/
-    FLOATS_REGEX         = /\A\s*(-?\d[\d\.]+)\s*\z/
+    INTEGERS_REGEX       = /\A(-?\d+)\z/
+    FLOATS_REGEX         = /\A(-?\d[\d\.]+)\z/
 
     # Use an atomic group (?>...) to avoid pathological backtracing from
     # malicious input as described in https://github.com/Shopify/liquid/issues/1357
-    RANGES_REGEX         = /\A\s*\(\s*(?>(\S+)\s*\.\.)\s*(\S+)\s*\)\s*\z/
+    RANGES_REGEX         = /\A\(\s*(?>(\S+)\s*\.\.)\s*(\S+)\s*\)\z/
 
     def self.parse(markup)
+      return nil unless markup
+
+      markup = markup.strip
+      if (markup.start_with?('"') && markup.end_with?('"')) ||
+         (markup.start_with?("'") && markup.end_with?("'"))
+        return markup[1..-2]
+      end
+
       case markup
-      when nil
-        nil
-      when SINGLE_QUOTED_STRING, DOUBLE_QUOTED_STRING
-        Regexp.last_match(1)
       when INTEGERS_REGEX
         Regexp.last_match(1).to_i
       when RANGES_REGEX
@@ -32,7 +34,6 @@ module Liquid
       when FLOATS_REGEX
         Regexp.last_match(1).to_f
       else
-        markup = markup.strip
         if LITERALS.key?(markup)
           LITERALS[markup]
         else

lib/liquid/forloop_drop.rb

@@ -1,6 +1,11 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type object
+  # @liquid_name forloop
+  # @liquid_summary
+  #   Information about a parent [`for` loop](/api/liquid/tags#for).
   class ForloopDrop < Drop
     def initialize(name, length, parentloop)
       @name       = name
@@ -9,33 +14,71 @@ module Liquid
       @index      = 0
     end
 
-    attr_reader :length, :parentloop
+    # @liquid_public_docs
+    # @liquid_name length
+    # @liquid_summary
+    #   The total number of iterations in the loop.
+    # @liquid_return [number]
+    attr_reader :length
+
+    # @liquid_public_docs
+    # @liquid_name parentloop
+    # @liquid_summary
+    #   The parent `forloop` object.
+    # @liquid_description
+    #   If the current `for` loop isn't nested inside another `for` loop, then `nil` is returned.
+    # @liquid_return [forloop]
+    attr_reader :parentloop
 
     def name
       Usage.increment('forloop_drop_name')
       @name
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current iteration.
+    # @liquid_return [number]
     def index
       @index + 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current iteration.
+    # @liquid_return [number]
     def index0
       @index
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current iteration, in reverse order.
+    # @liquid_return [number]
     def rindex
       @length - @index
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current iteration, in reverse order.
+    # @liquid_return [number]
     def rindex0
       @length - @index - 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current iteration is the first. Returns `false` if not.
+    # @liquid_return [boolean]
     def first
       @index == 0
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current iteration is the last. Returns `false` if not.
+    # @liquid_return [boolean]
     def last
       @index == @length - 1
     end

lib/liquid/locales/en.yml

@@ -13,15 +13,16 @@
       for_invalid_attribute: "Invalid attribute in for loop. Valid attributes are limit and offset"
       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}'"
+      inline_comment_invalid: "Syntax error in tag '#' - Each line of comments must be prefixed by the '#' character"
       invalid_delimiter: "'%{tag}' is not a valid delimiter for %{block_name} tags. use %{block_delimiter}"
+      render: "Syntax error in tag 'render' - Template name must be a quoted string"
+      table_row: "Syntax Error in 'table_row loop' - Valid syntax: table_row [item] in [collection] cols=3"
+      tag_never_closed: "'%{block_name}' tag was never closed"
+      tag_termination: "Tag '%{token}' was not properly terminated with regexp: %{tag_end}"
       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}"
+      unknown_tag: "Unknown tag '%{tag}'"
       variable_termination: "Variable '%{token}' was not properly terminated with regexp: %{tag_end}"
-      tag_never_closed: "'%{block_name}' tag was never closed"
-      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"
     disabled:

lib/liquid/partial_cache.rb

@@ -3,16 +3,16 @@
 module Liquid
   class PartialCache
     def self.load(template_name, context:, parse_context:)
-      cached_partials = (context.registers[:cached_partials] ||= {})
+      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)
+      file_system = context.registers[:file_system]
       source      = file_system.read_template_file(template_name)
 
       parse_context.partial = true
 
-      template_factory = (context.registers[:template_factory] ||= Liquid::TemplateFactory.new)
+      template_factory = context.registers[:template_factory]
       template = template_factory.for(template_name)
 
       partial = template.parse(source, parse_context)

lib/liquid/range_lookup.rb

@@ -12,6 +12,8 @@ module Liquid
       end
     end
 
+    attr_reader :start_obj, :end_obj
+
     def initialize(start_obj, end_obj)
       @start_obj = start_obj
       @end_obj   = end_obj
@@ -35,5 +37,11 @@ module Liquid
         Utils.to_integer(input)
       end
     end
+
+    class ParseTreeVisitor < Liquid::ParseTreeVisitor
+      def children
+        [@node.start_obj, @node.end_obj]
+      end
+    end
   end
 end

lib/liquid/register.rb

@@ -1,6 +0,0 @@
-# frozen_string_literal: true
-
-module Liquid
-  class Register
-  end
-end

lib/liquid/registers.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module Liquid
+  class Registers
+    attr_reader :static
+
+    def initialize(registers = {})
+      @static = registers.is_a?(Registers) ? registers.static : registers
+      @changes = {}
+    end
+
+    def []=(key, value)
+      @changes[key] = value
+    end
+
+    def [](key)
+      if @changes.key?(key)
+        @changes[key]
+      else
+        @static[key]
+      end
+    end
+
+    def delete(key)
+      @changes.delete(key)
+    end
+
+    UNDEFINED = Object.new
+
+    def fetch(key, default = UNDEFINED, &block)
+      if @changes.key?(key)
+        @changes.fetch(key)
+      elsif default != UNDEFINED
+        if block_given?
+          @static.fetch(key, &block)
+        else
+          @static.fetch(key, default)
+        end
+      else
+        @static.fetch(key, &block)
+      end
+    end
+
+    def key?(key)
+      @changes.key?(key) || @static.key?(key)
+    end
+  end
+
+  # Alias for backwards compatibility
+  StaticRegisters = Registers
+end

lib/liquid/standardfilters.rb

@@ -1,10 +1,12 @@
 # frozen_string_literal: true
 
 require 'cgi'
+require 'base64'
 require 'bigdecimal'
 
 module Liquid
   module StandardFilters
+    MAX_INT = (1 << 31) - 1
     HTML_ESCAPE = {
       '&' => '&amp;',
       '>' => '&gt;',
@@ -20,39 +22,99 @@ module Liquid
     )
     STRIP_HTML_TAGS = /<.*?>/m
 
-    # Return the size of an array or of an string
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Returns the size of a string or array.
+    # @liquid_description
+    #   The size of a string is the number of characters that the string includes. The size of an array is the number of items
+    #   in the array.
+    # @liquid_syntax variable | size
+    # @liquid_return [number]
     def size(input)
       input.respond_to?(:size) ? input.size : 0
     end
 
-    # convert an input string to DOWNCASE
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Converts a string to all lowercase characters.
+    # @liquid_syntax string | downcase
+    # @liquid_return [string]
     def downcase(input)
       input.to_s.downcase
     end
 
-    # convert an input string to UPCASE
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Converts a string to all uppercase characters.
+    # @liquid_syntax string | upcase
+    # @liquid_return [string]
     def upcase(input)
       input.to_s.upcase
     end
 
-    # capitalize words in the input centence
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Capitalizes the first word in a string.
+    # @liquid_syntax string | capitalize
+    # @liquid_return [string]
     def capitalize(input)
       input.to_s.capitalize
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Escapes a string.
+    # @liquid_syntax string | escape
+    # @liquid_return [string]
     def escape(input)
       CGI.escapeHTML(input.to_s) unless input.nil?
     end
     alias_method :h, :escape
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Escapes a string without changing characters that have already been escaped.
+    # @liquid_syntax string | escape_once
+    # @liquid_return [string]
     def escape_once(input)
       input.to_s.gsub(HTML_ESCAPE_ONCE_REGEXP, HTML_ESCAPE)
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Converts any URL-unsafe characters in a string to the
+    #   [percent-encoded](https://developer.mozilla.org/en-US/docs/Glossary/percent-encoding) equivalent.
+    # @liquid_description
+    #   > Note:
+    #   > Spaces are converted to a `+` character, instead of a percent-encoded character.
+    # @liquid_syntax string | url_encode
+    # @liquid_return [string]
     def url_encode(input)
       CGI.escape(input.to_s) unless input.nil?
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Decodes any [percent-encoded](https://developer.mozilla.org/en-US/docs/Glossary/percent-encoding) characters
+    #   in a string.
+    # @liquid_syntax string | url_decode
+    # @liquid_return [string]
     def url_decode(input)
       return if input.nil?
 
@@ -62,6 +124,64 @@ module Liquid
       result
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Encodes a string to [Base64 format](https://developer.mozilla.org/en-US/docs/Glossary/Base64).
+    # @liquid_syntax string | base64_encode
+    # @liquid_return [string]
+    def base64_encode(input)
+      Base64.strict_encode64(input.to_s)
+    end
+
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Decodes a string in [Base64 format](https://developer.mozilla.org/en-US/docs/Glossary/Base64).
+    # @liquid_syntax string | base64_decode
+    # @liquid_return [string]
+    def base64_decode(input)
+      Base64.strict_decode64(input.to_s)
+    rescue ::ArgumentError
+      raise Liquid::ArgumentError, "invalid base64 provided to base64_decode"
+    end
+
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Encodes a string to URL-safe [Base64 format](https://developer.mozilla.org/en-US/docs/Glossary/Base64).
+    # @liquid_syntax string | base64_url_safe_encode
+    # @liquid_return [string]
+    def base64_url_safe_encode(input)
+      Base64.urlsafe_encode64(input.to_s)
+    end
+
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Decodes a string in URL-safe [Base64 format](https://developer.mozilla.org/en-US/docs/Glossary/Base64).
+    # @liquid_syntax string | base64_url_safe_decode
+    # @liquid_return [string]
+    def base64_url_safe_decode(input)
+      Base64.urlsafe_decode64(input.to_s)
+    rescue ::ArgumentError
+      raise Liquid::ArgumentError, "invalid base64 provided to base64_url_safe_decode"
+    end
+
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Returns a substring or series of array items, starting at a given 0-based index.
+    # @liquid_description
+    #   By default, the substring has a length of one character, and the array series has one array item. However, you can
+    #   provide a second parameter to specify the number of characters or array items.
+    # @liquid_syntax string | slice
+    # @liquid_return [string]
     def slice(input, offset, length = nil)
       offset = Utils.to_integer(offset)
       length = length ? Utils.to_integer(length) : 1
@@ -73,7 +193,16 @@ module Liquid
       end
     end
 
-    # Truncate a string down to x characters
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Truncates a string down to a given number of characters.
+    # @liquid_description
+    #   If the specified number of characters is less than the length of the string, then an ellipsis (`...`) is appended to
+    #   the truncated string. The ellipsis is included in the character count of the truncated string.
+    # @liquid_syntax string | truncate: number
+    # @liquid_return [string]
     def truncate(input, length = 50, truncate_string = "...")
       return if input.nil?
       input_str = input.to_s
@@ -87,38 +216,90 @@ module Liquid
       input_str.length > length ? input_str[0...l].concat(truncate_string_str) : input_str
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Truncates a string down to a given number of words.
+    # @liquid_description
+    #   If the specified number of words is less than the number of words in the string, then an ellipsis (`...`) is appended to
+    #   the truncated string.
+    #
+    #   > Caution:
+    #   > HTML tags are treated as words, so you should strip any HTML from truncated content. If you don't strip HTML, then
+    #   > closing HTML tags can be removed, which can result in unexpected behavior.
+    # @liquid_syntax string | truncatewords: number
+    # @liquid_return [string]
     def truncatewords(input, words = 15, truncate_string = "...")
       return if input.nil?
-      wordlist = input.to_s.split
-      words    = Utils.to_integer(words)
+      input = input.to_s
+      words = Utils.to_integer(words)
+      words = 1 if words <= 0
 
-      l = words - 1
-      l = 0 if l < 0
+      wordlist = begin
+        input.split(" ", words + 1)
+      rescue RangeError
+        raise if words + 1 < MAX_INT
+        # e.g. integer #{words} too big to convert to `int'
+        raise Liquid::ArgumentError, "integer #{words} too big for truncatewords"
+      end
+      return input if wordlist.length <= words
 
-      wordlist.length > l ? wordlist[0..l].join(" ").concat(truncate_string.to_s) : input
+      wordlist.pop
+      wordlist.join(" ").concat(truncate_string.to_s)
     end
 
-    # Split input string into an array of substrings separated by given pattern.
-    #
-    # Example:
-    #   <div class="summary">{{ post | split '//' | first }}</div>
-    #
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Splits a string into an array of substrings based on a given separator.
+    # @liquid_syntax string | split: string
+    # @liquid_return [array[string]]
     def split(input, pattern)
       input.to_s.split(pattern.to_s)
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Strips all whitespace from the left and right of a string.
+    # @liquid_syntax string | strip
+    # @liquid_return [string]
     def strip(input)
       input.to_s.strip
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Strips all whitespace from the left of a string.
+    # @liquid_syntax string | lstrip
+    # @liquid_return [string]
     def lstrip(input)
       input.to_s.lstrip
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Strips all whitespace from the right of a string.
+    # @liquid_syntax string | rstrip
+    # @liquid_return [string]
     def rstrip(input)
       input.to_s.rstrip
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Strips all HTML tags from a string.
+    # @liquid_syntax string | strip_html
+    # @liquid_return [string]
     def strip_html(input)
       empty  = ''
       result = input.to_s.gsub(STRIP_HTML_BLOCKS, empty)
@@ -126,18 +307,35 @@ module Liquid
       result
     end
 
-    # Remove all newlines from the string
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Strips all newline characters (line breaks) from a string.
+    # @liquid_syntax string | strip_newlines
+    # @liquid_return [string]
     def strip_newlines(input)
       input.to_s.gsub(/\r?\n/, '')
     end
 
-    # Join elements of the array with certain character between them
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Combines all of the items in an array into a single string, separated by a space.
+    # @liquid_syntax array | join
+    # @liquid_return [string]
     def join(input, glue = ' ')
       InputIterator.new(input, context).join(glue)
     end
 
-    # Sort elements of the array
-    # provide optional property with which to sort an array of hashes or drops
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Sorts the items in an array in case-sensitive alphabetical, or numerical, order.
+    # @liquid_syntax array | sort
+    # @liquid_return [array[untyped]]
     def sort(input, property = nil)
       ary = InputIterator.new(input, context)
 
@@ -156,8 +354,17 @@ module Liquid
       end
     end
 
-    # Sort elements of an array ignoring case if strings
-    # provide optional property with which to sort an array of hashes or drops
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Sorts the items in an array in case-insensitive alphabetical order.
+    # @liquid_description
+    #   > Caution:
+    #   > You shouldn't use the `sort_natural` filter to sort numerical values. When comparing items an array, each item is converted to a
+    #   > string, so sorting on numerical values can lead to unexpected results.
+    # @liquid_syntax array | sort_natural
+    # @liquid_return [array[untyped]]
     def sort_natural(input, property = nil)
       ary = InputIterator.new(input, context)
 
@@ -176,30 +383,48 @@ module Liquid
       end
     end
 
-    # Filter the elements of an array to those with a certain property value.
-    # By default the target is any truthy value.
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Filters an array to include only items with a specific property value.
+    # @liquid_description
+    #   This requires you to provide both the property name and the associated value.
+    # @liquid_syntax array | where: string, string
+    # @liquid_return [array[untyped]]
     def where(input, property, target_value = nil)
       ary = InputIterator.new(input, context)
 
       if ary.empty?
         []
-      elsif ary.first.respond_to?(:[]) && target_value.nil?
-        begin
-          ary.select { |item| item[property] }
+      elsif target_value.nil?
+        ary.select do |item|
+          item[property]
         rescue TypeError
           raise_property_error(property)
+        rescue NoMethodError
+          return nil unless item.respond_to?(:[])
+          raise
         end
-      elsif ary.first.respond_to?(:[])
-        begin
-          ary.select { |item| item[property] == target_value }
+      else
+        ary.select do |item|
+          item[property] == target_value
         rescue TypeError
           raise_property_error(property)
+        rescue NoMethodError
+          return nil unless item.respond_to?(:[])
+          raise
         end
       end
     end
 
-    # Remove duplicate elements from an array
-    # provide optional property with which to determine uniqueness
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Removes any duplicate items in an array.
+    # @liquid_syntax array | uniq
+    # @liquid_return [array[untyped]]
     def uniq(input, property = nil)
       ary = InputIterator.new(input, context)
 
@@ -207,22 +432,37 @@ module Liquid
         ary.uniq
       elsif ary.empty? # The next two cases assume a non-empty array.
         []
-      elsif ary.first.respond_to?(:[])
-        begin
-          ary.uniq { |a| a[property] }
+      else
+        ary.uniq do |item|
+          item[property]
         rescue TypeError
           raise_property_error(property)
+        rescue NoMethodError
+          return nil unless item.respond_to?(:[])
+          raise
         end
       end
     end
 
-    # Reverse the elements of an array
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Reverses the order of the items in an array.
+    # @liquid_syntax array | reverse
+    # @liquid_return [array[untyped]]
     def reverse(input)
       ary = InputIterator.new(input, context)
       ary.reverse
     end
 
-    # map/collect on a given property
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Creates an array of values from a specific property of the items in an array.
+    # @liquid_syntax array | map: string
+    # @liquid_return [array[untyped]]
     def map(input, property)
       InputIterator.new(input, context).map do |e|
         e = e.call if e.is_a?(Proc)
@@ -238,8 +478,13 @@ module Liquid
       raise_property_error(property)
     end
 
-    # Remove nils within an array
-    # provide optional property with which to check for nil
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Removes any `nil` items from an array.
+    # @liquid_syntax array | compact
+    # @liquid_return [array[untyped]]
     def compact(input, property = nil)
       ary = InputIterator.new(input, context)
 
@@ -247,40 +492,116 @@ module Liquid
         ary.compact
       elsif ary.empty? # The next two cases assume a non-empty array.
         []
-      elsif ary.first.respond_to?(:[])
-        begin
-          ary.reject { |a| a[property].nil? }
+      else
+        ary.reject do |item|
+          item[property].nil?
         rescue TypeError
           raise_property_error(property)
+        rescue NoMethodError
+          return nil unless item.respond_to?(:[])
+          raise
         end
       end
     end
 
-    # Replace occurrences of a string with another
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Replaces any instance of a substring inside a string with a given string.
+    # @liquid_syntax string | replace: string, string
+    # @liquid_return [string]
     def replace(input, string, replacement = '')
       input.to_s.gsub(string.to_s, replacement.to_s)
     end
 
-    # Replace the first occurrences of a string with another
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Replaces the first instance of a substring inside a string with a given string.
+    # @liquid_syntax string | replace_first: string, string
+    # @liquid_return [string]
     def replace_first(input, string, replacement = '')
       input.to_s.sub(string.to_s, replacement.to_s)
     end
 
-    # remove a substring
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Replaces the last instance of a substring inside a string with a given string.
+    # @liquid_syntax string | replace_last: string, string
+    # @liquid_return [string]
+    def replace_last(input, string, replacement)
+      input = input.to_s
+      string = string.to_s
+      replacement = replacement.to_s
+
+      start_index = input.rindex(string)
+
+      return input unless start_index
+
+      output = input.dup
+      output[start_index, string.length] = replacement
+      output
+    end
+
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Removes any instance of a substring inside a string.
+    # @liquid_syntax string | remove: string
+    # @liquid_return [string]
     def remove(input, string)
-      input.to_s.gsub(string.to_s, '')
+      replace(input, string, '')
     end
 
-    # remove the first occurrences of a substring
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Removes the first instance of a substring inside a string.
+    # @liquid_syntax string | remove_first: string
+    # @liquid_return [string]
     def remove_first(input, string)
-      input.to_s.sub(string.to_s, '')
+      replace_first(input, string, '')
     end
 
-    # add one string to another
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Removes the last instance of a substring inside a string.
+    # @liquid_syntax string | remove_last: string
+    # @liquid_return [string]
+    def remove_last(input, string)
+      replace_last(input, string, '')
+    end
+
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Adds a given string to the end of a string.
+    # @liquid_syntax string | append: string
+    # @liquid_return [string]
     def append(input, string)
       input.to_s + string.to_s
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Concatenates (combines) two arrays.
+    # @liquid_description
+    #   > Note:
+    #   > The `concat` filter won't filter out duplicates. If you want to remove duplicates, then you need to use the
+    #   > [`uniq` filter](/api/liquid/filters#uniq).
+    # @liquid_syntax array | concat: array
+    # @liquid_return [array[untyped]]
     def concat(input, array)
       unless array.respond_to?(:to_ary)
         raise ArgumentError, "concat filter requires an array argument"
@@ -288,14 +609,26 @@ module Liquid
       InputIterator.new(input, context).concat(array)
     end
 
-    # prepend a string to another
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Adds a given string to the beginning of a string.
+    # @liquid_syntax string | prepend: string
+    # @liquid_return [string]
     def prepend(input, string)
       string.to_s + input.to_s
     end
 
-    # Add <br /> tags in front of all newlines in input string
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Converts newlines (`\n`) in a string to HTML line breaks (`<br>`).
+    # @liquid_syntax string | newline_to_br
+    # @liquid_return [string]
     def newline_to_br(input)
-      input.to_s.gsub(/\n/, "<br />\n")
+      input.to_s.gsub(/\r?\n/, "<br />\n")
     end
 
     # Reformat a date using Ruby's core Time#strftime( string ) -> string
@@ -337,58 +670,106 @@ module Liquid
       date.strftime(format.to_s)
     end
 
-    # Get the first element of the passed in array
-    #
-    # Example:
-    #    {{ product.images | first | to_img }}
-    #
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Returns the first item in an array.
+    # @liquid_syntax array | first
+    # @liquid_return [untyped]
     def first(array)
       array.first if array.respond_to?(:first)
     end
 
-    # Get the last element of the passed in array
-    #
-    # Example:
-    #    {{ product.images | last | to_img }}
-    #
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category array
+    # @liquid_summary
+    #   Returns the last item in an array.
+    # @liquid_syntax array | last
+    # @liquid_return [untyped]
     def last(array)
       array.last if array.respond_to?(:last)
     end
 
-    # absolute value
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Returns the absolute value of a number.
+    # @liquid_syntax number | abs
+    # @liquid_return [number]
     def abs(input)
       result = Utils.to_number(input).abs
       result.is_a?(BigDecimal) ? result.to_f : result
     end
 
-    # addition
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Adds two numbers.
+    # @liquid_syntax number | plus: number
+    # @liquid_return [number]
     def plus(input, operand)
       apply_operation(input, operand, :+)
     end
 
-    # subtraction
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Subtracts a given number from another number.
+    # @liquid_syntax number | minus: number
+    # @liquid_return [number]
     def minus(input, operand)
       apply_operation(input, operand, :-)
     end
 
-    # multiplication
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Multiplies a number by a given number.
+    # @liquid_syntax number | times: number
+    # @liquid_return [number]
     def times(input, operand)
       apply_operation(input, operand, :*)
     end
 
-    # division
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Divides a number by a given number.
+    # @liquid_syntax number | divided_by: number
+    # @liquid_return [number]
     def divided_by(input, operand)
       apply_operation(input, operand, :/)
     rescue ::ZeroDivisionError => e
       raise Liquid::ZeroDivisionError, e.message
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Returns the remainder of dividing a number by a given number.
+    # @liquid_syntax number | modulo: number
+    # @liquid_return [number]
     def modulo(input, operand)
       apply_operation(input, operand, :%)
     rescue ::ZeroDivisionError => e
       raise Liquid::ZeroDivisionError, e.message
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Rounds a number to the nearest integer.
+    # @liquid_syntax number | round
+    # @liquid_return [number]
     def round(input, n = 0)
       result = Utils.to_number(input).round(Utils.to_number(n))
       result = result.to_f if result.is_a?(BigDecimal)
@@ -398,18 +779,39 @@ module Liquid
       raise Liquid::FloatDomainError, e.message
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Rounds a number up to the nearest integer.
+    # @liquid_syntax number | ceil
+    # @liquid_return [number]
     def ceil(input)
       Utils.to_number(input).ceil.to_i
     rescue ::FloatDomainError => e
       raise Liquid::FloatDomainError, e.message
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Rounds a number down to the nearest integer.
+    # @liquid_syntax number | floor
+    # @liquid_return [number]
     def floor(input)
       Utils.to_number(input).floor.to_i
     rescue ::FloatDomainError => e
       raise Liquid::FloatDomainError, e.message
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Limits a number to a minimum value.
+    # @liquid_syntax number | at_least
+    # @liquid_return [number]
     def at_least(input, n)
       min_value = Utils.to_number(n)
 
@@ -418,6 +820,13 @@ module Liquid
       result.is_a?(BigDecimal) ? result.to_f : result
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category math
+    # @liquid_summary
+    #   Limits a number to a maximum value.
+    # @liquid_syntax number | at_most
+    # @liquid_return [number]
     def at_most(input, n)
       max_value = Utils.to_number(n)
 
@@ -426,19 +835,21 @@ module Liquid
       result.is_a?(BigDecimal) ? result.to_f : result
     end
 
-    # Set a default value when the input is nil, false or empty
-    #
-    # Example:
-    #    {{ product.title | default: "No Title" }}
-    #
-    # Use `allow_false` when an input should only be tested against nil or empty and not false.
-    #
-    # Example:
-    #    {{ product.title | default: "No Title", allow_false: true }}
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category default
+    # @liquid_summary
+    #   Sets a default value for any variable whose value is one of the following:
     #
+    #   - [`empty`](/api/liquid/basics#empty)
+    #   - [`false`](/api/liquid/basics#truthy-and-falsy)
+    #   - [`nil`](/api/liquid/basics#nil)
+    # @liquid_syntax variable | default: variable
+    # @liquid_return [untyped]
+    # @liquid_optional_param allow_false [boolean] Whether to use false values instead of the default.
     def default(input, default_value = '', options = {})
       options = {} unless options.is_a?(Hash)
-      false_check = options['allow_false'] ? input.nil? : !input
+      false_check = options['allow_false'] ? input.nil? : !Liquid::Utils.to_liquid_value(input)
       false_check || (input.respond_to?(:empty?) && input.empty?) ? default_value : input
     end
 
@@ -456,10 +867,16 @@ module Liquid
     end
 
     def nil_safe_compare(a, b)
-      if !a.nil? && !b.nil?
-        a <=> b
+      result = a <=> b
+
+      if result
+        result
+      elsif a.nil?
+        1
+      elsif b.nil?
+        -1
       else
-        a.nil? ? 1 : -1
+        raise Liquid::ArgumentError, "cannot sort values of incompatible types"
       end
     end
 
@@ -514,8 +931,9 @@ module Liquid
 
       def each
         @input.each do |e|
+          e = e.respond_to?(:to_liquid) ? e.to_liquid : e
           e.context = @context if e.respond_to?(:context=)
-          yield(e.respond_to?(:to_liquid) ? e.to_liquid : e)
+          yield(e)
         end
       end
     end

lib/liquid/static_registers.rb

@@ -1,44 +0,0 @@
-# frozen_string_literal: true
-
-module Liquid
-  class StaticRegisters
-    attr_reader :static
-
-    def initialize(registers = {})
-      @static    = registers.is_a?(StaticRegisters) ? registers.static : registers
-      @registers = {}
-    end
-
-    def []=(key, value)
-      @registers[key] = value
-    end
-
-    def [](key)
-      if @registers.key?(key)
-        @registers[key]
-      else
-        @static[key]
-      end
-    end
-
-    def delete(key)
-      @registers.delete(key)
-    end
-
-    UNDEFINED = Object.new
-
-    def fetch(key, default = UNDEFINED, &block)
-      if @registers.key?(key)
-        @registers.fetch(key)
-      elsif default != UNDEFINED
-        @static.fetch(key, default, &block)
-      else
-        @static.fetch(key, &block)
-      end
-    end
-
-    def key?(key)
-      @registers.key?(key) || @static.key?(key)
-    end
-  end
-end

lib/liquid/strainer_factory.rb

@@ -7,25 +7,30 @@ module Liquid
 
     def add_global_filter(filter)
       strainer_class_cache.clear
-      global_filters << filter
+      GlobalCache.add_filter(filter)
     end
 
     def create(context, filters = [])
       strainer_from_cache(filters).new(context)
     end
 
-    private
-
-    def global_filters
-      @global_filters ||= []
+    def global_filter_names
+      GlobalCache.filter_method_names
     end
 
+    GlobalCache = Class.new(StrainerTemplate)
+
+    private
+
     def strainer_from_cache(filters)
-      strainer_class_cache[filters] ||= begin
-        klass = Class.new(StrainerTemplate)
-        global_filters.each { |f| klass.add_filter(f) }
-        filters.each { |f| klass.add_filter(f) }
-        klass
+      if filters.empty?
+        GlobalCache
+      else
+        strainer_class_cache[filters] ||= begin
+          klass = Class.new(GlobalCache)
+          filters.each { |f| klass.add_filter(f) }
+          klass
+        end
       end
     end
 

lib/liquid/strainer_template.rb

@@ -31,6 +31,15 @@ module Liquid
         filter_methods.include?(method.to_s)
       end
 
+      def inherited(subclass)
+        super
+        subclass.instance_variable_set(:@filter_methods, @filter_methods.dup)
+      end
+
+      def filter_method_names
+        filter_methods.map(&:to_s).to_a
+      end
+
       private
 
       def filter_methods

lib/liquid/tablerowloop_drop.rb

@@ -1,6 +1,11 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type object
+  # @liquid_name tablerowloop
+  # @liquid_summary
+  #   Information about a parent [`tablerow` loop](/api/liquid/tags#tablerow).
   class TablerowloopDrop < Drop
     def initialize(length, cols)
       @length = length
@@ -10,40 +15,92 @@ module Liquid
       @index  = 0
     end
 
-    attr_reader :length, :col, :row
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The total number of iterations in the loop.
+    # @liquid_return [number]
+    attr_reader :length
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current column.
+    # @liquid_return [number]
+    attr_reader :col
+
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of current row.
+    # @liquid_return [number]
+    attr_reader :row
+
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current iteration.
+    # @liquid_return [number]
     def index
       @index + 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current iteration.
+    # @liquid_return [number]
     def index0
       @index
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current column.
+    # @liquid_return [number]
     def col0
       @col - 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 1-based index of the current iteration, in reverse order.
+    # @liquid_return [number]
     def rindex
       @length - @index
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   The 0-based index of the current iteration, in reverse order.
+    # @liquid_return [number]
     def rindex0
       @length - @index - 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current iteration is the first. Returns `false` if not.
+    # @liquid_return [boolean]
     def first
       @index == 0
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current iteration is the last. Returns `false` if not.
+    # @liquid_return [boolean]
     def last
       @index == @length - 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current column is the first in the row. Returns `false` if not.
+    # @liquid_return [boolean]
     def col_first
       @col == 1
     end
 
+    # @liquid_public_docs
+    # @liquid_summary
+    #   Returns `true` if the current column is the last in the row. Returns `false` if not.
+    # @liquid_return [boolean]
     def col_last
       @col == @cols
     end

lib/liquid/tags/assign.rb

@@ -1,14 +1,18 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Assign sets a variable in your template.
-  #
-  #   {% assign foo = 'monkey' %}
-  #
-  # You can then use the variable later in the page.
-  #
-  #  {{ foo }}
-  #
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category variable
+  # @liquid_name assign
+  # @liquid_summary
+  #   Creates a new variable.
+  # @liquid_description
+  #   You can create variables of any [basic type](/api/liquid/basics#types), [object](/api/liquid/objects), or object property.
+  # @liquid_syntax
+  #   {% assign variable_name = value %}
+  # @liquid_syntax_keyword variable_name The name of the variable being created.
+  # @liquid_syntax_keyword value The value you want to assign to the variable.
   class Assign < Tag
     Syntax = /(#{VariableSignature}+)\s*=\s*(.*)\s*/om
 

lib/liquid/tags/break.rb

@@ -10,6 +10,14 @@ module Liquid
   #      {% endif %}
   #    {% endfor %}
   #
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name break
+  # @liquid_summary
+  #   Stops a [`for` loop](/api/liquid/tags#for) from iterating.
+  # @liquid_syntax
+  #   {% break %}
   class Break < Tag
     INTERRUPT = BreakInterrupt.new.freeze
 

lib/liquid/tags/capture.rb

@@ -1,17 +1,20 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Capture stores the result of a block into a variable without rendering it inplace.
-  #
-  #   {% capture heading %}
-  #     Monkeys!
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category variable
+  # @liquid_name capture
+  # @liquid_summary
+  #   Creates a new variable with a string value.
+  # @liquid_description
+  #   You can create complex strings with Liquid logic and variables.
+  # @liquid_syntax
+  #   {% capture variable %}
+  #     value
   #   {% endcapture %}
-  #   ...
-  #   <h1>{{ heading }}</h1>
-  #
-  # Capture is useful for saving content for use later in your template, such as
-  # in a sidebar or footer.
-  #
+  # @liquid_syntax_keyword variable The name of the variable being created.
+  # @liquid_syntax_keyword value The value you want to assign to the variable.
   class Capture < Block
     Syntax = /(#{VariableSignature}+)/o
 

lib/liquid/tags/case.rb

@@ -1,6 +1,27 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category conditional
+  # @liquid_name case
+  # @liquid_summary
+  #   Renders a specific expression depending on the value of a specific variable.
+  # @liquid_syntax
+  #   {% case variable %}
+  #     {% when first_value %}
+  #       first_expression
+  #     {% when second_value %}
+  #       second_expression
+  #     {% else %}
+  #       third_expression
+  #   {% endcase %}
+  # @liquid_syntax_keyword variable The name of the variable you want to base your case statement on.
+  # @liquid_syntax_keyword first_value A specific value to check for.
+  # @liquid_syntax_keyword second_value A specific value to check for.
+  # @liquid_syntax_keyword first_expression An expression to be rendered when the variable's value matches `first_value`.
+  # @liquid_syntax_keyword second_expression An expression to be rendered when the variable's value matches `second_value`.
+  # @liquid_syntax_keyword third_expression An expression to be rendered when the variable's value has no match.
   class Case < Block
     Syntax     = /(#{QuotedFragment})/o
     WhenSyntax = /(#{QuotedFragment})(?:(?:\s+or\s+|\s*\,\s*)(#{QuotedFragment}.*))?/om
@@ -52,7 +73,14 @@ module Liquid
       @blocks.each do |block|
         if block.else?
           block.attachment.render_to_output_buffer(context, output) if execute_else_block
-        elsif block.evaluate(context)
+          next
+        end
+
+        result = Liquid::Utils.to_liquid_value(
+          block.evaluate(context)
+        )
+
+        if result
           execute_else_block = false
           block.attachment.render_to_output_buffer(context, output)
         end

lib/liquid/tags/comment.rb

@@ -1,6 +1,19 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name comment
+  # @liquid_summary
+  #   Prevents an expression from being rendered or output.
+  # @liquid_description
+  #   Any text inside `comment` tags won't be output, and any Liquid code won't be rendered.
+  # @liquid_syntax
+  #   {% comment %}
+  #     content
+  #   {% endcomment %}
+  # @liquid_syntax_keyword content The content of the comment.
   class Comment < Block
     def render_to_output_buffer(_context, output)
       output

lib/liquid/tags/continue.rb

@@ -1,15 +1,14 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Continue tag to be used to break out of a for loop.
-  #
-  # == Basic Usage:
-  #    {% for item in collection %}
-  #      {% if item.condition %}
-  #        {% continue %}
-  #      {% endif %}
-  #    {% endfor %}
-  #
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name continue
+  # @liquid_summary
+  #   Causes a [`for` loop](/api/liquid/tags#for) to skip to the next iteration.
+  # @liquid_syntax
+  #   {% continue %}
   class Continue < Tag
     INTERRUPT = ContinueInterrupt.new.freeze
 

lib/liquid/tags/cycle.rb

@@ -1,18 +1,19 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Cycle is usually used within a loop to alternate between values, like colors or DOM classes.
-  #
-  #   {% for item in items %}
-  #     <div class="{% cycle 'red', 'green', 'blue' %}"> {{ item }} </div>
-  #   {% end %}
-  #
-  #    <div class="red"> Item one </div>
-  #    <div class="green"> Item two </div>
-  #    <div class="blue"> Item three </div>
-  #    <div class="red"> Item four </div>
-  #    <div class="green"> Item five</div>
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name cycle
+  # @liquid_summary
+  #   Loops through a group of strings and outputs them one at a time for each iteration of a [`for` loop](/api/liquid/tags#for).
+  # @liquid_description
+  #   The `cycle` tag must be used inside a `for` loop.
   #
+  #   > Tip:
+  #   > Use the `cycle` tag to output text in a predictable pattern. For example, to apply odd/even classes to rows in a table.
+  # @liquid_syntax
+  #   {% cycle string, string, ... %}
   class Cycle < Tag
     SimpleSyntax = /\A#{QuotedFragment}+/o
     NamedSyntax  = /\A(#{QuotedFragment})\s*\:\s*(.*)/om

lib/liquid/tags/decrement.rb

@@ -1,24 +1,23 @@
 # frozen_string_literal: true
 
 module Liquid
-  # decrement is used in a place where one needs to insert a counter
-  #     into a template, and needs the counter to survive across
-  #     multiple instantiations of the template.
-  #     NOTE: decrement is a pre-decrement, --i,
-  #           while increment is post:      i++.
-  #
-  #     (To achieve the survival, the application must keep the context)
-  #
-  #     if the variable does not exist, it is created with value 0.
-
-  #   Hello: {% decrement variable %}
-  #
-  # gives you:
-  #
-  #    Hello: -1
-  #    Hello: -2
-  #    Hello: -3
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category variable
+  # @liquid_name decrement
+  # @liquid_summary
+  #   Creates a new variable, with a default value of -1, that's decreased by 1 with each subsequent call.
+  # @liquid_description
+  #   Variables that are declared with `decrement` are unique to the [layout](/themes/architecture/layouts), [template](/themes/architecture/templates),
+  #   or [section](/themes/architecture/sections) file that they're created in. However, the variable is shared across
+  #   [snippets](/themes/architecture#snippets) included in the file.
   #
+  #   Similarly, variables that are created with `decrement` are independent from those created with [`assign`](/api/liquid/tags#assign)
+  #   and [`capture`](/api/liquid/tags#capture). However, `decrement` and [`increment`](/api/liquid/tags#increment) share
+  #   variables.
+  # @liquid_syntax
+  #   {% decrement variable_name %}
+  # @liquid_syntax_keyword variable_name The name of the variable being decremented.
   class Decrement < Tag
     def initialize(tag_name, markup, options)
       super

lib/liquid/tags/echo.rb

@@ -1,17 +1,26 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Echo outputs an expression
-  #
-  #   {% echo monkey %}
-  #   {% echo user.name %}
-  #
-  # This is identical to variable output syntax, like {{ foo }}, but works
-  # inside {% liquid %} tags. The full syntax is supported, including filters:
-  #
-  #   {% echo user | link %}
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name echo
+  # @liquid_summary
+  #   Outputs an expression.
+  # @liquid_description
+  #   Using the `echo` tag is the same as wrapping an expression in curly brackets (`{{` and `}}`). However, unlike the curly
+  #   bracket method, you can use the `echo` tag inside [`liquid` tags](/api/liquid/tags#liquid).
   #
+  #   > Tip:
+  #   > You can use [filters](/api/liquid/filters) on expressions inside `echo` tags.
+  # @liquid_syntax
+  #   {% liquid
+  #     echo expression
+  #   %}
+  # @liquid_syntax_keyword expression The expression to be output.
   class Echo < Tag
+    attr_reader :variable
+
     def initialize(tag_name, markup, parse_context)
       super
       @variable = Variable.new(markup, parse_context)
@@ -20,6 +29,12 @@ module Liquid
     def render(context)
       @variable.render_to_output_buffer(context, +'')
     end
+
+    class ParseTreeVisitor < Liquid::ParseTreeVisitor
+      def children
+        [@node.variable]
+      end
+    end
   end
 
   Template.register_tag('echo', Echo)

lib/liquid/tags/for.rb

@@ -1,50 +1,29 @@
 # frozen_string_literal: true
 
 module Liquid
-  # "For" iterates over an array or collection.
-  # Several useful variables are available to you within the loop.
-  #
-  # == Basic usage:
-  #    {% for item in collection %}
-  #      {{ forloop.index }}: {{ item.name }}
-  #    {% endfor %}
-  #
-  # == Advanced usage:
-  #    {% for item in collection %}
-  #      <div {% if forloop.first %}class="first"{% endif %}>
-  #        Item {{ forloop.index }}: {{ item.name }}
-  #      </div>
-  #    {% else %}
-  #      There is nothing in the collection.
-  #    {% endfor %}
-  #
-  # You can also define a limit and offset much like SQL.  Remember
-  # that offset starts at 0 for the first item.
-  #
-  #    {% for item in collection limit:5 offset:10 %}
-  #      {{ item.name }}
-  #    {% end %}
-  #
-  #  To reverse the for loop simply use {% for item in collection reversed %} (note that the flag's spelling is different to the filter `reverse`)
-  #
-  # == Available variables:
-  #
-  # forloop.name:: 'item-collection'
-  # forloop.length:: Length of the loop
-  # forloop.index:: The current item's position in the collection;
-  #                 forloop.index starts at 1.
-  #                 This is helpful for non-programmers who start believe
-  #                 the first item in an array is 1, not 0.
-  # forloop.index0:: The current item's position in the collection
-  #                  where the first item is 0
-  # forloop.rindex:: Number of items remaining in the loop
-  #                  (length - index) where 1 is the last item.
-  # forloop.rindex0:: Number of items remaining in the loop
-  #                   where 0 is the last item.
-  # forloop.first:: Returns true if the item is the first item.
-  # forloop.last:: Returns true if the item is the last item.
-  # forloop.parentloop:: Provides access to the parent loop, if present.
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name for
+  # @liquid_summary
+  #   Renders an expression for every item in an array.
+  # @liquid_description
+  #   You can do a maximum of 50 iterations with a `for` loop. If you need to iterate over more than 50 items, then use the
+  #   [`paginate` tag](/api/liquid/tags#paginate) to split the items over multiple pages.
   #
+  #   > Tip:
+  #   > Every `for` loop has an associated [`forloop` object](/api/liquid/objects#forloop) with information about the loop.
+  # @liquid_syntax
+  #   {% for variable in array %}
+  #     expression
+  #   {% endfor %}
+  # @liquid_syntax_keyword variable The current item in the array.
+  # @liquid_syntax_keyword array The array to iterate over.
+  # @liquid_syntax_keyword expression The expression to render for each iteration.
+  # @liquid_optional_param limit [number] The number of iterations to perform.
+  # @liquid_optional_param offset [number] The 1-based index to start iterating at.
+  # @liquid_optional_param range [untyped] A custom numeric range to iterate over.
+  # @liquid_optional_param reversed [untyped] Iterate in reverse order.
   class For < Block
     Syntax = /\A(#{VariableSegment}+)\s+in\s+(#{QuotedFragment}+)\s*(reversed)?/o
 

lib/liquid/tags/if.rb

@@ -1,16 +1,18 @@
 # frozen_string_literal: true
 
 module Liquid
-  # If is the conditional block
-  #
-  #   {% if user.admin %}
-  #     Admin user!
-  #   {% else %}
-  #     Not admin user
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category conditional
+  # @liquid_name if
+  # @liquid_summary
+  #   Renders an expression if a specific condition is `true`.
+  # @liquid_syntax
+  #   {% if condition %}
+  #     expression
   #   {% endif %}
-  #
-  #    There are {% if count < 5 %} less {% else %} more {% endif %} items than you need.
-  #
+  # @liquid_syntax_keyword condition The condition to evaluate.
+  # @liquid_syntax_keyword expression The expression to render if the condition is met.
   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
@@ -50,7 +52,11 @@ module Liquid
 
     def render_to_output_buffer(context, output)
       @blocks.each do |block|
-        if block.evaluate(context)
+        result = Liquid::Utils.to_liquid_value(
+          block.evaluate(context)
+        )
+
+        if result
           return block.attachment.render_to_output_buffer(context, output)
         end
       end

lib/liquid/tags/include.rb

@@ -1,20 +1,22 @@
 # frozen_string_literal: true
 
 module Liquid
-  # Include allows templates to relate with other templates
-  #
-  # Simply include another template:
-  #
-  #   {% include 'product' %}
-  #
-  # Include a template with a local variable:
-  #
-  #   {% include 'product' with products[0] %}
-  #
-  # Include a template for a collection:
-  #
-  #   {% include 'product' for products %}
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category theme
+  # @liquid_name include
+  # @liquid_summary
+  #   Renders a [snippet](/themes/architecture#snippets).
+  # @liquid_description
+  #   Inside the snippet, you can access and alter variables that are [created](/api/liquid/tags#variable-tags) outside of the
+  #   snippet.
+  # @liquid_syntax
+  #   {% include 'filename' %}
+  # @liquid_syntax_keyword filename The name of the snippet to render, without the `.liquid` extension.
+  # @liquid_deprecated
+  #   Deprecated because the way that variables are handled reduces performance and makes code harder to both read and maintain.
   #
+  #   The `include` tag has been replaced by [`render`](/api/liquid/tags#render).
   class Include < Tag
     prepend Tag::Disableable
 

lib/liquid/tags/increment.rb

@@ -1,21 +1,23 @@
 # frozen_string_literal: true
 
 module Liquid
-  # increment is used in a place where one needs to insert a counter
-  #     into a template, and needs the counter to survive across
-  #     multiple instantiations of the template.
-  #     (To achieve the survival, the application must keep the context)
-  #
-  #     if the variable does not exist, it is created with value 0.
-  #
-  #   Hello: {% increment variable %}
-  #
-  # gives you:
-  #
-  #    Hello: 0
-  #    Hello: 1
-  #    Hello: 2
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category variable
+  # @liquid_name increment
+  # @liquid_summary
+  #   Creates a new variable, with a default value of 0, that's increased by 1 with each subsequent call.
+  # @liquid_description
+  #   Variables that are declared with `increment` are unique to the [layout](/themes/architecture/layouts), [template](/themes/architecture/templates),
+  #   or [section](/themes/architecture/sections) file that they're created in. However, the variable is shared across
+  #   [snippets](/themes/architecture#snippets) included in the file.
   #
+  #   Similarly, variables that are created with `increment` are independent from those created with [`assign`](/api/liquid/tags#assign)
+  #   and [`capture`](/api/liquid/tags#capture). However, `increment` and [`decrement`](/api/liquid/tags#decrement) share
+  #   variables.
+  # @liquid_syntax
+  #   {% increment variable_name %}
+  # @liquid_syntax_keyword variable_name The name of the variable being incremented.
   class Increment < Tag
     def initialize(tag_name, markup, options)
       super

lib/liquid/tags/inline_comment.rb

@@ -1,15 +1,43 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name inline_comment
+  # @liquid_summary
+  #   Prevents an expression from being rendered or output.
+  # @liquid_description
+  #   Any text inside an `inline_comment` tag won't be rendered or output.
+  #
+  #   You can create multi-line inline comments. However, each line must begin with a `#`.
+  # @liquid_syntax
+  #   {% # content %}
+  # @liquid_syntax_keyword content The content of the comment.
   class InlineComment < Tag
+    def initialize(tag_name, markup, options)
+      super
+
+      # Semantically, a comment should only ignore everything after it on the line.
+      # Currently, this implementation doesn't support mixing a comment with another tag
+      # but we need to reserve future support for this and prevent the introduction
+      # of inline comments from being backward incompatible change.
+      #
+      # As such, we're forcing users to put a # symbol on every line otherwise this
+      # tag will throw an error.
+      if markup.match?(/\n\s*[^#\s]/)
+        raise SyntaxError, options[:locale].t("errors.syntax.inline_comment_invalid")
+      end
+    end
+
+    def render_to_output_buffer(_context, output)
+      output
+    end
+
     def blank?
       true
     end
-
-    def render_to_output_buffer(_context, _output)
-    end
   end
 
-  Template.register_tag('--', InlineComment)
+  Template.register_tag('#', InlineComment)
 end
-

lib/liquid/tags/raw.rb

@@ -1,6 +1,17 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category syntax
+  # @liquid_name raw
+  # @liquid_summary
+  #   Outputs any Liquid code as text instead of rendering it.
+  # @liquid_syntax
+  #   {% raw %}
+  #     expression
+  #   {% endraw %}
+  # @liquid_syntax_keyword expression The expression to be output without being rendered.
   class Raw < Block
     Syntax = /\A\s*\z/
     FullTokenPossiblyInvalid = /\A(.*)#{TagStart}\s*(\w+)\s*(.*)?#{TagEnd}\z/om

lib/liquid/tags/render.rb

@@ -1,13 +1,37 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category theme
+  # @liquid_name render
+  # @liquid_summary
+  #   Renders a [snippet](/themes/architecture#snippets) or [app block](/themes/architecture/sections/section-schema#render-app-blocks).
+  # @liquid_description
+  #   Inside snippets and app blocks, you can't directly access variables that are [created](/api/liquid/tags#variable-tags) outside
+  #   of the snippet or app block. However, you can [specify variables as parameters](/api/liquid/tags#render-passing-variables-to-snippets)
+  #   to pass outside variables to snippets.
+  #
+  #   While you can't directly access created variables, you can access global objects, as well as any objects that are
+  #   directly accessible outside the snippet or app block. For example, a snippet or app block inside the [product template](/themes/architecture/templates/product)
+  #   can access the [`product` object](/api/liquid/objects#product), and a snippet or app block inside a [section](/themes/architecture/sections)
+  #   can access the [`section` object](/api/liquid/objects#section).
+  #
+  #   Outside a snippet or app block, you can't access variables created inside the snippet or app block.
+  #
+  #   > Note:
+  #   > When you render a snippet using the `render` tag, you can't use the [`include` tag](/api/liquid/tags#include)
+  #   > inside the snippet.
+  # @liquid_syntax
+  #   {% render 'filename' %}
+  # @liquid_syntax_keyword filename The name of the snippet to render, without the `.liquid` extension.
   class Render < Tag
     FOR = 'for'
     SYNTAX = /(#{QuotedString}+)(\s+(with|#{FOR})\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
 
     disable_tags "include"
 
-    attr_reader :template_name_expr, :attributes
+    attr_reader :template_name_expr, :variable_name_expr, :attributes
 
     def initialize(tag_name, markup, options)
       super
@@ -34,9 +58,9 @@ module Liquid
     end
 
     def render_tag(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, options[:locale].t("errors.argument.include") unless template_name
+      # The expression should be a String literal, which parses to a String object
+      template_name = @template_name_expr
+      raise ::ArgumentError unless template_name.is_a?(String)
 
       partial = PartialCache.load(
         template_name,
@@ -75,6 +99,7 @@ module Liquid
       def children
         [
           @node.template_name_expr,
+          @node.variable_name_expr,
         ] + @node.attributes.values
       end
     end

lib/liquid/tags/table_row.rb

@@ -1,6 +1,28 @@
 # frozen_string_literal: true
 
 module Liquid
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category iteration
+  # @liquid_name tablerow
+  # @liquid_summary
+  #   Generates HTML table rows for every item in an array.
+  # @liquid_description
+  #   The `tablerow` tag must be wrapped in HTML `<table>` and `</table>` tags.
+  #
+  #   > Tip:
+  #   > Every `tablerow` loop has an associated [`tablerowloop` object](/api/liquid/objects#tablerowloop) with information about the loop.
+  # @liquid_syntax
+  #   {% tablerow variable in array %}
+  #     expression
+  #   {% endtablerow %}
+  # @liquid_syntax_keyword variable The current item in the array.
+  # @liquid_syntax_keyword array The array to iterate over.
+  # @liquid_syntax_keyword expression The expression to render.
+  # @liquid_optional_param cols [number] The number of columns that the table should have.
+  # @liquid_optional_param limit [number] The number of iterations to perform.
+  # @liquid_optional_param offset [number] The 1-based index to start iterating at.
+  # @liquid_optional_param range [untyped] A custom numeric range to iterate over.
   class TableRow < Block
     Syntax = /(\w+)\s+in\s+(#{QuotedFragment}+)/o
 

lib/liquid/tags/unless.rb

@@ -3,21 +3,40 @@
 require_relative 'if'
 
 module Liquid
-  # Unless is a conditional just like 'if' but works on the inverse logic.
-  #
-  #   {% unless x < 0 %} x is greater than zero {% endunless %}
-  #
+  # @liquid_public_docs
+  # @liquid_type tag
+  # @liquid_category conditional
+  # @liquid_name unless
+  # @liquid_summary
+  #   Renders an expression unless a specific condition is `true`.
+  # @liquid_description
+  #   > Tip:
+  #   > Similar to the [`if` tag](/api/liquid/tags#if), you can use `elsif` to add more conditions to an `unless` tag.
+  # @liquid_syntax
+  #   {% unless condition %}
+  #     expression
+  #   {% endunless %}
+  # @liquid_syntax_keyword condition The condition to evaluate.
+  # @liquid_syntax_keyword expression The expression to render unless the condition is met.
   class Unless < If
     def render_to_output_buffer(context, output)
       # First condition is interpreted backwards ( if not )
       first_block = @blocks.first
-      unless first_block.evaluate(context)
+      result = Liquid::Utils.to_liquid_value(
+        first_block.evaluate(context)
+      )
+
+      unless result
         return first_block.attachment.render_to_output_buffer(context, output)
       end
 
       # After the first condition unless works just like if
       @blocks[1..-1].each do |block|
-        if block.evaluate(context)
+        result = Liquid::Utils.to_liquid_value(
+          block.evaluate(context)
+        )
+
+        if result
           return block.attachment.render_to_output_buffer(context, output)
         end
       end

lib/liquid/template.rb

@@ -167,15 +167,14 @@ module Liquid
 
       output = nil
 
-      context_register = context.registers.is_a?(StaticRegisters) ? context.registers.static : context.registers
-
       case args.last
       when Hash
         options = args.pop
         output  = options[:output] if options[:output]
+        static_registers = context.registers.static
 
         options[:registers]&.each do |key, register|
-          context_register[key] = register
+          static_registers[key] = register
         end
 
         apply_options_to_context(context, options)

lib/liquid/tokenizer.rb

@@ -5,7 +5,7 @@ module Liquid
     attr_reader :line_number, :for_liquid_tag
 
     def initialize(source, line_numbers = false, line_number: nil, for_liquid_tag: false)
-      @source         = source
+      @source         = source.to_s.to_str
       @line_number    = line_number || (line_numbers ? 1 : nil)
       @for_liquid_tag = for_liquid_tag
       @tokens         = tokenize
@@ -24,7 +24,7 @@ module Liquid
     private
 
     def tokenize
-      return [] if @source.to_s.empty?
+      return [] if @source.empty?
 
       return @source.split("\n") if @for_liquid_tag
 

lib/liquid/utils.rb

@@ -81,5 +81,13 @@ module Liquid
     rescue ::ArgumentError
       nil
     end
+
+    def self.to_liquid_value(obj)
+      # Enable "obj" to represent itself as a primitive value like integer, string, or boolean
+      return obj.to_liquid_value if obj.respond_to?(:to_liquid_value)
+
+      # Otherwise return the object itself
+      obj
+    end
   end
 end

lib/liquid/variable.rb

@@ -47,7 +47,7 @@ module Liquid
 
       name_markup   = Regexp.last_match(1)
       filter_markup = Regexp.last_match(2)
-      @name         = Expression.parse(name_markup)
+      @name         = parse_context.parse_expression(name_markup)
       if filter_markup =~ FilterMarkupRegex
         filters = Regexp.last_match(1).scan(FilterParser)
         filters.each do |f|
@@ -65,7 +65,7 @@ module Liquid
 
       return if p.look(:end_of_string)
 
-      @name = Expression.parse(p.expression)
+      @name = parse_context.parse_expression(p.expression)
       while p.consume?(:pipe)
         filtername = p.consume(:id)
         filterargs = p.consume?(:colon) ? parse_filterargs(p) : []
@@ -122,9 +122,9 @@ module Liquid
       unparsed_args.each do |a|
         if (matches = a.match(JustTagAttributes))
           keyword_args           ||= {}
-          keyword_args[matches[1]] = Expression.parse(matches[2])
+          keyword_args[matches[1]] = parse_context.parse_expression(matches[2])
         else
-          filter_args << Expression.parse(a)
+          filter_args << parse_context.parse_expression(a)
         end
       end
       result = [filter_name, filter_args]

lib/liquid/variable_lookup.rb

@@ -2,8 +2,7 @@
 
 module Liquid
   class VariableLookup
-    SQUARE_BRACKETED = /\A\[(.*)\]\z/m
-    COMMAND_METHODS  = ['size', 'first', 'last'].freeze
+    COMMAND_METHODS = ['size', 'first', 'last'].freeze
 
     attr_reader :name, :lookups
 
@@ -15,8 +14,8 @@ module Liquid
       lookups = markup.scan(VariableParser)
 
       name = lookups.shift
-      if name =~ SQUARE_BRACKETED
-        name = Expression.parse(Regexp.last_match(1))
+      if name&.start_with?('[') && name&.end_with?(']')
+        name = Expression.parse(name[1..-2])
       end
       @name = name
 
@@ -25,14 +24,18 @@ module Liquid
 
       @lookups.each_index do |i|
         lookup = lookups[i]
-        if lookup =~ SQUARE_BRACKETED
-          lookups[i] = Expression.parse(Regexp.last_match(1))
+        if lookup&.start_with?('[') && lookup&.end_with?(']')
+          lookups[i] = Expression.parse(lookup[1..-2])
         elsif COMMAND_METHODS.include?(lookup)
           @command_flags |= 1 << i
         end
       end
     end
 
+    def lookup_command?(lookup_index)
+      @command_flags & (1 << lookup_index) != 0
+    end
+
     def evaluate(context)
       name   = context.evaluate(@name)
       object = context.find_variable(name)
@@ -40,6 +43,9 @@ module Liquid
       @lookups.each_index do |i|
         key = context.evaluate(@lookups[i])
 
+        # Cast "key" to its liquid value to enable it to act as a primitive value
+        key = Liquid::Utils.to_liquid_value(key)
+
         # If object is a hash- or array-like object we look for the
         # presence of the key and if its available we return it
         if object.respond_to?(:[]) &&
@@ -53,7 +59,7 @@ module Liquid
           # Some special cases. If the part wasn't in square brackets and
           # no key with the same name was found we interpret following calls
           # as commands and call them on the current object
-        elsif @command_flags & (1 << i) != 0 && object.respond_to?(key)
+        elsif lookup_command?(i) && object.respond_to?(key)
           object = object.send(key).to_liquid
 
           # No key was present with the desired value and it wasn't one of the directly supported

lib/liquid/version.rb

@@ -2,5 +2,5 @@
 # frozen_string_literal: true
 
 module Liquid
-  VERSION = "5.0.0"
+  VERSION = "5.4.0"
 end

liquid.gemspec

@@ -17,13 +17,12 @@ 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     = ">= 2.5.0"
+  s.required_ruby_version     = ">= 2.7.0"
   s.required_rubygems_version = ">= 1.3.7"
 
   s.metadata['allowed_push_host'] = 'https://rubygems.org'
 
-  s.test_files  = Dir.glob("{test}/**/*")
-  s.files       = Dir.glob("{lib}/**/*") + %w(LICENSE README.md)
+  s.files = Dir.glob("{lib}/**/*") + %w(LICENSE README.md)
 
   s.extra_rdoc_files = ["History.md", "README.md"]
 

performance/shopify/database.rb

@@ -3,11 +3,19 @@
 require 'yaml'
 
 module Database
+  DATABASE_FILE_PATH = "#{__dir__}/vision.database.yml"
+
   # Load the standard vision toolkit database and re-arrage it to be simply exportable
   # to liquid as assigns. All this is based on Shopify
   def self.tables
     @tables ||= begin
-      db = YAML.load_file("#{__dir__}/vision.database.yml")
+      db =
+        if YAML.respond_to?(:unsafe_load_file) # Only Psych 4+ can use unsafe_load_file
+          # unsafe_load_file is needed for YAML references
+          YAML.unsafe_load_file(DATABASE_FILE_PATH)
+        else
+          YAML.load_file(DATABASE_FILE_PATH)
+        end
 
       # From vision source
       db['products'].each do |product|

performance/theme_runner.rb

@@ -3,7 +3,7 @@
 # This profiler run simulates Shopify.
 # We are looking in the tests directory for liquid files and render them within the designated layout file.
 # We will also export a substantial database to liquid which the templates can render values of.
-# All this is to make the benchmark as non syntetic as possible. All templates and tests are lifted from
+# All this is to make the benchmark as non synthetic as possible. All templates and tests are lifted from
 # direct real-world usage and the profiler measures code that looks very similar to the way it looks in
 # Shopify which is likely the biggest user of liquid in the world which something to the tune of several
 # million Template#render calls a day.

test/integration/context_test.rb

@@ -24,7 +24,7 @@ class ContextSensitiveDrop < Liquid::Drop
   end
 end
 
-class Category < Liquid::Drop
+class Category
   attr_accessor :name
 
   def initialize(name)
@@ -36,8 +36,9 @@ class Category < Liquid::Drop
   end
 end
 
-class CategoryDrop
+class CategoryDrop < Liquid::Drop
   attr_accessor :category, :context
+
   def initialize(category)
     @category = category
   end
@@ -405,45 +406,42 @@ class ContextTest < Minitest::Test
   end
 
   def test_lambda_is_called_once
+    @global = 0
+
     @context['callcount'] = proc {
-      @global ||= 0
-      @global  += 1
+      @global += 1
       @global.to_s
     }
 
     assert_equal('1', @context['callcount'])
     assert_equal('1', @context['callcount'])
     assert_equal('1', @context['callcount'])
-
-    @global = nil
   end
 
   def test_nested_lambda_is_called_once
+    @global = 0
+
     @context['callcount'] = { "lambda" => proc {
-                                            @global ||= 0
-                                            @global  += 1
+                                            @global += 1
                                             @global.to_s
                                           } }
 
     assert_equal('1', @context['callcount.lambda'])
     assert_equal('1', @context['callcount.lambda'])
     assert_equal('1', @context['callcount.lambda'])
-
-    @global = nil
   end
 
   def test_lambda_in_array_is_called_once
+    @global = 0
+
     @context['callcount'] = [1, 2, proc {
-                                     @global ||= 0
-                                     @global  += 1
+                                     @global += 1
                                      @global.to_s
                                    }, 4, 5]
 
     assert_equal('1', @context['callcount[2]'])
     assert_equal('1', @context['callcount[2]'])
     assert_equal('1', @context['callcount[2]'])
-
-    @global = nil
   end
 
   def test_access_to_context_from_proc
@@ -461,6 +459,7 @@ class ContextTest < Minitest::Test
   end
 
   def test_interrupt_avoids_object_allocations
+    @context.interrupt? # ruby 3.0.0 allocates on the first call
     assert_no_object_allocations do
       @context.interrupt?
     end
@@ -530,7 +529,7 @@ class ContextTest < Minitest::Test
     registers = {
       my_register: :my_value,
     }
-    super_context = Context.new({}, {}, StaticRegisters.new(registers))
+    super_context = Context.new({}, {}, Registers.new(registers))
     super_context.registers[:my_register] = :my_alt_value
     subcontext                            = super_context.new_isolated_subcontext
     assert_equal(:my_value, subcontext.registers[:my_register])
@@ -619,6 +618,20 @@ class ContextTest < Minitest::Test
     end
   end
 
+  def test_context_always_uses_static_registers
+    registers = {
+      my_register: :my_value,
+    }
+    c = Context.new({}, {}, registers)
+    assert_instance_of(Registers, c.registers)
+    assert_equal(:my_value, c.registers[:my_register])
+
+    r = Registers.new(registers)
+    c = Context.new({}, {}, r)
+    assert_instance_of(Registers, c.registers)
+    assert_equal(:my_value, c.registers[:my_register])
+  end
+
   private
 
   def assert_no_object_allocations

test/integration/filter_kwarg_test.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class FilterKwargTest < Minitest::Test
+  module KwargFilter
+    def html_tag(_tag, attributes)
+      attributes
+        .map { |key, value| "#{key}='#{value}'" }
+        .join(' ')
+    end
+  end
+
+  include Liquid
+
+  def test_can_parse_data_kwargs
+    with_global_filter(KwargFilter) do
+      assert_equal(
+        "data-src='src' data-widths='100, 200'",
+        Template.parse("{{ 'img' | html_tag: data-src: 'src', data-widths: '100, 200' }}").render(nil, nil)
+      )
+    end
+  end
+end

test/integration/inline_comment_test.rb

@@ -1,17 +0,0 @@
-# frozen_string_literal: true
-
-require 'test_helper'
-
-class InlineCommentTest < Minitest::Test
-  include Liquid
-
-  def test_basic_usage
-    template_source = <<-END_TEMPLATE
-    foo{% # this is a comment %}bar
-    END_TEMPLATE
-    template        = Template.parse(template_source)
-    rendered        = template.render!
-    assert_equal("foobar", rendered.strip)
-  end
-end
-

test/integration/profiler_test.rb

@@ -3,6 +3,27 @@
 require 'test_helper'
 
 class ProfilerTest < Minitest::Test
+  class TestDrop < Liquid::Drop
+    def initialize(value)
+      super()
+      @value = value
+    end
+
+    def to_s
+      artificial_execution_time
+
+      @value
+    end
+
+    private
+
+    # Monotonic clock precision fluctuate based on the operating system
+    # By introducing a small sleep we ensure ourselves to register a non zero unit of time
+    def artificial_execution_time
+      sleep(Process.clock_getres(Process::CLOCK_MONOTONIC))
+    end
+  end
+
   include Liquid
 
   class ProfilingFileSystem
@@ -198,16 +219,22 @@ class ProfilerTest < Minitest::Test
 
   def test_profiling_supports_self_time
     t = Template.parse("{% for item in collection %} {{ item }} {% endfor %}", profile: true)
-    t.render!("collection" => ["one", "two"])
-    leaf = t.profiler[0].children[0]
+    collection = [
+      TestDrop.new("one"),
+      TestDrop.new("two"),
+    ]
+    output = t.render!("collection" => collection)
+    assert_equal(" one  two ", output)
 
-    assert_operator(leaf.self_time, :>, 0)
+    leaf = t.profiler[0].children[0]
+    assert_operator(leaf.self_time, :>, 0.0)
   end
 
   def test_profiling_supports_total_time
-    t = Template.parse("{% if true %} {% increment test %} {{ test }} {% endif %}", profile: true)
-    t.render!
+    t = Template.parse("{% if true %} {{ test }} {% endif %}", profile: true)
+    output = t.render!("test" => TestDrop.new("one"))
+    assert_equal(" one ", output)
 
-    assert_operator(t.profiler[0].total_time, :>, 0)
+    assert_operator(t.profiler[0].total_time, :>, 0.0)
   end
 end

test/integration/standard_filter_test.rb

@@ -3,10 +3,6 @@
 
 require 'test_helper'
 
-class Filters
-  include Liquid::StandardFilters
-end
-
 class TestThing
   attr_reader :foo
 
@@ -29,8 +25,24 @@ class TestThing
 end
 
 class TestDrop < Liquid::Drop
-  def test
-    "testfoo"
+  def initialize(value:)
+    @value = value
+  end
+
+  attr_reader :value
+
+  def registers
+    { @value => @context.registers[@value] }
+  end
+end
+
+class TestModel
+  def initialize(value:)
+    @value = value
+  end
+
+  def to_liquid
+    TestDrop.new(value: @value)
   end
 end
 
@@ -53,10 +65,13 @@ class NumberLikeThing < Liquid::Drop
 end
 
 class StandardFiltersTest < Minitest::Test
+  Filters = Class.new(Liquid::StrainerTemplate)
+  Filters.add_filter(Liquid::StandardFilters)
+
   include Liquid
 
   def setup
-    @filters = Filters.new
+    @filters = Filters.new(Context.new)
   end
 
   def test_size
@@ -145,6 +160,40 @@ class StandardFiltersTest < Minitest::Test
     assert_equal('&lt;strong&gt;Hulk&lt;/strong&gt;', @filters.escape_once('&lt;strong&gt;Hulk</strong>'))
   end
 
+  def test_base64_encode
+    assert_equal('b25lIHR3byB0aHJlZQ==', @filters.base64_encode('one two three'))
+    assert_equal('', @filters.base64_encode(nil))
+  end
+
+  def test_base64_decode
+    assert_equal('one two three', @filters.base64_decode('b25lIHR3byB0aHJlZQ=='))
+
+    exception = assert_raises(Liquid::ArgumentError) do
+      @filters.base64_decode("invalidbase64")
+    end
+
+    assert_equal('Liquid error: invalid base64 provided to base64_decode', exception.message)
+  end
+
+  def test_base64_url_safe_encode
+    assert_equal(
+      'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXogQUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVogMTIzNDU2Nzg5MCAhQCMkJV4mKigpLT1fKy8_Ljo7W117fVx8',
+      @filters.base64_url_safe_encode('abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 !@#$%^&*()-=_+/?.:;[]{}\|')
+    )
+    assert_equal('', @filters.base64_url_safe_encode(nil))
+  end
+
+  def test_base64_url_safe_decode
+    assert_equal(
+      'abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 !@#$%^&*()-=_+/?.:;[]{}\|',
+      @filters.base64_url_safe_decode('YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXogQUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVogMTIzNDU2Nzg5MCAhQCMkJV4mKigpLT1fKy8_Ljo7W117fVx8')
+    )
+    exception = assert_raises(Liquid::ArgumentError) do
+      @filters.base64_url_safe_decode("invalidbase64")
+    end
+    assert_equal('Liquid error: invalid base64 provided to base64_url_safe_decode', exception.message)
+  end
+
   def test_url_encode
     assert_equal('foo%2B1%40example.com', @filters.url_encode('[email protected]'))
     assert_equal('1', @filters.url_encode(1))
@@ -171,10 +220,17 @@ class StandardFiltersTest < Minitest::Test
     assert_equal('one two three', @filters.truncatewords('one two three'))
     assert_equal(
       'Two small (13&#8221; x 5.5&#8221; x 10&#8221; high) baskets fit inside one large basket (13&#8221;...',
-        @filters.truncatewords('Two small (13&#8221; x 5.5&#8221; x 10&#8221; high) baskets fit inside one large basket (13&#8221; x 16&#8221; x 10.5&#8221; high) with cover.', 15)
+      @filters.truncatewords('Two small (13&#8221; x 5.5&#8221; x 10&#8221; high) baskets fit inside one large basket (13&#8221; x 16&#8221; x 10.5&#8221; high) with cover.', 15)
     )
     assert_equal("测试测试测试测试", @filters.truncatewords('测试测试测试测试', 5))
     assert_equal('one two1', @filters.truncatewords("one two three", 2, 1))
+    assert_equal('one two three...', @filters.truncatewords("one  two\tthree\nfour", 3))
+    assert_equal('one two...', @filters.truncatewords("one two three four", 2))
+    assert_equal('one...', @filters.truncatewords("one two three four", 0))
+    exception = assert_raises(Liquid::ArgumentError) do
+      @filters.truncatewords("one two three four", 1 << 31)
+    end
+    assert_equal("Liquid error: integer #{1 << 31} too big for truncatewords", exception.message)
   end
 
   def test_strip_html
@@ -218,8 +274,8 @@ class StandardFiltersTest < Minitest::Test
       { "price" => 1, "handle" => "gamma" },
       { "price" => 2, "handle" => "epsilon" },
       { "price" => 4, "handle" => "alpha" },
-      { "handle" => "delta" },
       { "handle" => "beta" },
+      { "handle" => "delta" },
     ]
     assert_equal(expectation, @filters.sort(input, "price"))
   end
@@ -322,8 +378,9 @@ class StandardFiltersTest < Minitest::Test
     assert_equal(["foo"], @filters.uniq("foo"))
     assert_equal([1, 3, 2, 4], @filters.uniq([1, 1, 3, 2, 3, 1, 4, 3, 2, 1]))
     assert_equal([{ "a" => 1 }, { "a" => 3 }, { "a" => 2 }], @filters.uniq([{ "a" => 1 }, { "a" => 3 }, { "a" => 1 }, { "a" => 2 }], "a"))
-    testdrop = TestDrop.new
-    assert_equal([testdrop], @filters.uniq([testdrop, TestDrop.new], 'test'))
+    test_drop = TestDrop.new(value: "test")
+    test_drop_alternate = TestDrop.new(value: "test")
+    assert_equal([test_drop], @filters.uniq([test_drop, test_drop_alternate], 'value'))
   end
 
   def test_uniq_empty_array
@@ -382,6 +439,16 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result("woot: 1", '{{ foo | map: "whatever" }}', "foo" => [t])
   end
 
+  def test_map_calls_context=
+    model = TestModel.new(value: :test)
+
+    template = Template.parse('{{ foo | map: "registers" }}')
+    template.registers[:test] = 1234
+    template.assigns['foo'] = [model]
+
+    assert_template_result("{:test=>1234}", template.render!)
+  end
+
   def test_map_on_hashes
     assert_template_result("4217", '{{ thing | map: "foo" | map: "bar" }}',
       "thing" => { "foo" => [{ "bar" => 42 }, { "bar" => 17 }] })
@@ -400,9 +467,9 @@ class StandardFiltersTest < Minitest::Test
   end
 
   def test_map_over_proc
-    drop  = TestDrop.new
+    drop  = TestDrop.new(value: "testfoo")
     p     = proc { drop }
-    templ = '{{ procs | map: "test" }}'
+    templ = '{{ procs | map: "value" }}'
     assert_template_result("testfoo", templ, "procs" => [p])
   end
 
@@ -498,19 +565,31 @@ class StandardFiltersTest < Minitest::Test
   end
 
   def test_replace
-    assert_equal('2 2 2 2', @filters.replace('1 1 1 1', '1', 2))
+    assert_equal('b b b b', @filters.replace('a a a a', 'a', 'b'))
     assert_equal('2 2 2 2', @filters.replace('1 1 1 1', 1, 2))
-    assert_equal('2 1 1 1', @filters.replace_first('1 1 1 1', '1', 2))
+    assert_equal('1 1 1 1', @filters.replace('1 1 1 1', 2, 3))
+    assert_template_result('2 2 2 2', "{{ '1 1 1 1' | replace: '1', 2 }}")
+
+    assert_equal('b a a a', @filters.replace_first('a a a a', 'a', 'b'))
     assert_equal('2 1 1 1', @filters.replace_first('1 1 1 1', 1, 2))
+    assert_equal('1 1 1 1', @filters.replace_first('1 1 1 1', 2, 3))
     assert_template_result('2 1 1 1', "{{ '1 1 1 1' | replace_first: '1', 2 }}")
+
+    assert_equal('a a a b', @filters.replace_last('a a a a', 'a', 'b'))
+    assert_equal('1 1 1 2', @filters.replace_last('1 1 1 1', 1, 2))
+    assert_equal('1 1 1 1', @filters.replace_last('1 1 1 1', 2, 3))
+    assert_template_result('1 1 1 2', "{{ '1 1 1 1' | replace_last: '1', 2 }}")
   end
 
   def test_remove
     assert_equal('   ', @filters.remove("a a a a", 'a'))
-    assert_equal('   ', @filters.remove("1 1 1 1", 1))
-    assert_equal('a a a', @filters.remove_first("a a a a", 'a '))
-    assert_equal(' 1 1 1', @filters.remove_first("1 1 1 1", 1))
-    assert_template_result('a a a', "{{ 'a a a a' | remove_first: 'a ' }}")
+    assert_template_result('   ', "{{ '1 1 1 1' | remove: 1 }}")
+
+    assert_equal('b a a', @filters.remove_first("a b a a", 'a '))
+    assert_template_result(' 1 1 1', "{{ '1 1 1 1' | remove_first: 1 }}")
+
+    assert_equal('a a b', @filters.remove_last("a a b a", ' a'))
+    assert_template_result('1 1 1 ', "{{ '1 1 1 1' | remove_last: 1 }}")
   end
 
   def test_pipes_in_string_arguments
@@ -539,6 +618,7 @@ class StandardFiltersTest < Minitest::Test
 
   def test_newlines_to_br
     assert_template_result("a<br />\nb<br />\nc", "{{ source | newline_to_br }}", 'source' => "a\nb\nc")
+    assert_template_result("a<br />\nb<br />\nc", "{{ source | newline_to_br }}", 'source' => "a\r\nb\nc")
   end
 
   def test_plus
@@ -686,6 +766,8 @@ class StandardFiltersTest < Minitest::Test
     assert_equal("bar", @filters.default([], "bar"))
     assert_equal("bar", @filters.default({}, "bar"))
     assert_template_result('bar', "{{ false | default: 'bar' }}")
+    assert_template_result('bar', "{{ drop | default: 'bar' }}", 'drop' => BooleanDrop.new(false))
+    assert_template_result('Yay', "{{ drop | default: 'bar' }}", 'drop' => BooleanDrop.new(true))
   end
 
   def test_default_handle_false
@@ -696,6 +778,8 @@ class StandardFiltersTest < Minitest::Test
     assert_equal("bar", @filters.default([], "bar", "allow_false" => true))
     assert_equal("bar", @filters.default({}, "bar", "allow_false" => true))
     assert_template_result('false', "{{ false | default: 'bar', allow_false: true }}")
+    assert_template_result('Nay', "{{ drop | default: 'bar', allow_false: true }}", 'drop' => BooleanDrop.new(false))
+    assert_template_result('Yay', "{{ drop | default: 'bar', allow_false: true }}", 'drop' => BooleanDrop.new(true))
   end
 
   def test_cannot_access_private_methods
@@ -724,6 +808,18 @@ class StandardFiltersTest < Minitest::Test
     assert_equal(expectation, @filters.where(input, "ok"))
   end
 
+  def test_where_string_keys
+    input = [
+      "alpha", "beta", "gamma", "delta"
+    ]
+
+    expectation = [
+      "beta",
+    ]
+
+    assert_equal(expectation, @filters.where(input, "be"))
+  end
+
   def test_where_no_key_set
     input = [
       { "handle" => "alpha", "ok" => true },
@@ -769,7 +865,7 @@ class StandardFiltersTest < Minitest::Test
   end
 
   def test_all_filters_never_raise_non_liquid_exception
-    test_drop = TestDrop.new
+    test_drop = TestDrop.new(value: "test")
     test_drop.context = Context.new
     test_enum = TestEnumerable.new
     test_enum.context = Context.new
@@ -794,19 +890,14 @@ class StandardFiltersTest < Minitest::Test
       { 1 => "bar" },
       ["foo", 123, nil, true, false, Drop, ["foo"], { foo: "bar" }],
     ]
-    test_types.each do |first|
-      test_types.each do |other|
-        (@filters.methods - Object.methods).each do |method|
-          arg_count = @filters.method(method).arity
-          arg_count *= -1 if arg_count < 0
-          inputs = [first]
-          inputs << ([other] * (arg_count - 1)) if arg_count > 1
-          begin
-            @filters.send(method, *inputs)
-          rescue Liquid::ArgumentError, Liquid::ZeroDivisionError
-            nil
-          end
-        end
+    StandardFilters.public_instance_methods(false).each do |method|
+      arg_count = @filters.method(method).arity
+      arg_count *= -1 if arg_count < 0
+
+      test_types.repeated_permutation(arg_count) do |args|
+        @filters.send(method, *args)
+      rescue Liquid::Error
+        nil
       end
     end
   end

test/integration/tags/include_tag_test.rb

@@ -96,12 +96,12 @@ class IncludeTagTest < Minitest::Test
 
   def test_include_tag_with_alias
     assert_template_result("Product: Draft 151cm ",
-                           "{% include 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% include 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_include_tag_for_alias
     assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-                           "{% include 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% include 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_include_tag_with_default_name

test/integration/tags/inline_comment_test.rb

@@ -0,0 +1,69 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class InlineCommentTest < Minitest::Test
+  include Liquid
+
+  def test_inline_comment_returns_nothing
+    assert_template_result('', '{%- # this is an inline comment -%}')
+    assert_template_result('', '{%-# this is an inline comment -%}')
+    assert_template_result('', '{% # this is an inline comment %}')
+    assert_template_result('', '{%# this is an inline comment %}')
+  end
+
+  def test_inline_comment_does_not_require_a_space_after_the_pound_sign
+    assert_template_result('', '{%#this is an inline comment%}')
+  end
+
+  def test_liquid_inline_comment_returns_nothing
+    assert_template_result('Hey there, how are you doing today?', <<~LIQUID)
+      {%- liquid
+        # This is how you'd write a block comment in a liquid tag.
+        # It looks a lot like what you'd have in ruby.
+
+        # You can use it as inline documentation in your
+        # liquid blocks to explain why you're doing something.
+        echo "Hey there, "
+
+        # It won't affect the output.
+        echo "how are you doing today?"
+      -%}
+    LIQUID
+  end
+
+  def test_inline_comment_can_be_written_on_multiple_lines
+    assert_template_result('', <<~LIQUID)
+      {%-
+        # That kind of block comment is also allowed.
+        # It would only be a stylistic difference.
+
+        # Much like JavaScript's /* */ comments and their
+        # leading * on new lines.
+      -%}
+    LIQUID
+  end
+
+  def test_inline_comment_multiple_pound_signs
+    assert_template_result('', <<~LIQUID)
+      {%- liquid
+        ######################################
+        # We support comments like this too. #
+        ######################################
+      -%}
+    LIQUID
+  end
+
+  def test_inline_comments_require_the_pound_sign_on_every_new_line
+    assert_match_syntax_error("Each line of comments must be prefixed by the '#' character", <<~LIQUID)
+      {%-
+        # some comment
+        echo 'hello world'
+      -%}
+    LIQUID
+  end
+
+  def test_inline_comment_does_not_support_nested_tags
+    assert_template_result(' -%}', "{%- # {% echo 'hello world' %} -%}")
+  end
+end

test/integration/tags/render_tag_test.rb

@@ -151,7 +151,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm ",
-                           "{% render 'product' with products[0] %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product' with products[0] %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_with_alias
@@ -161,7 +161,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm ",
-                           "{% render 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product_alias' with products[0] as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_for_alias
@@ -171,7 +171,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-                           "{% render 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product_alias' for products as product %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_for
@@ -181,7 +181,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-                           "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_forloop
@@ -190,7 +190,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("Product: Draft 151cm first  index:1 Product: Element 155cm  last index:2 ",
-                           "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% render 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
   end
 
   def test_render_tag_for_drop
@@ -199,7 +199,7 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("123",
-                           "{% render 'loop' for loop as value %}", "loop" => TestEnumerable.new)
+      "{% render 'loop' for loop as value %}", "loop" => TestEnumerable.new)
   end
 
   def test_render_tag_with_drop
@@ -208,6 +208,6 @@ class RenderTagTest < Minitest::Test
     )
 
     assert_template_result("TestEnumerable",
-                           "{% render 'loop' with loop as value %}", "loop" => TestEnumerable.new)
+      "{% render 'loop' with loop as value %}", "loop" => TestEnumerable.new)
   end
 end

test/integration/template_test.rb

@@ -323,4 +323,18 @@ class TemplateTest < Minitest::Test
     result = t.render('x' => 1, 'y' => 5)
     assert_equal('12345', result)
   end
+
+  def test_source_string_subclass
+    string_subclass = Class.new(String) do
+      # E.g. ActiveSupport::SafeBuffer does this, so don't just rely on to_s to return a String
+      def to_s
+        self
+      end
+    end
+    source = string_subclass.new("{% assign x = 2 -%} x= {{- x }}")
+    assert_instance_of(string_subclass, source)
+    output = Template.parse(source).render!
+    assert_equal("x=2", output)
+    assert_instance_of(String, output)
+  end
 end

test/integration/variable_test.rb

@@ -15,6 +15,33 @@ class VariableTest < Minitest::Test
     assert_template_result('foobar', '{{ foo }}', 'foo' => ThingWithToLiquid.new)
   end
 
+  def test_variable_lookup_calls_to_liquid_value
+    assert_template_result('1', '{{ foo }}', 'foo' => IntegerDrop.new('1'))
+    assert_template_result('2', '{{ list[foo] }}', 'foo' => IntegerDrop.new('1'), 'list' => [1, 2, 3])
+    assert_template_result('one', '{{ list[foo] }}', 'foo' => IntegerDrop.new('1'), 'list' => { 1 => 'one' })
+    assert_template_result('Yay', '{{ foo }}', 'foo' => BooleanDrop.new(true))
+    assert_template_result('YAY', '{{ foo | upcase }}', 'foo' => BooleanDrop.new(true))
+  end
+
+  def test_if_tag_calls_to_liquid_value
+    assert_template_result('one', '{% if foo == 1 %}one{% endif %}', 'foo' => IntegerDrop.new('1'))
+    assert_template_result('one', '{% if 0 < foo %}one{% endif %}', 'foo' => IntegerDrop.new('1'))
+    assert_template_result('one', '{% if foo > 0 %}one{% endif %}', 'foo' => IntegerDrop.new('1'))
+    assert_template_result('true', '{% if foo == true %}true{% endif %}', 'foo' => BooleanDrop.new(true))
+    assert_template_result('true', '{% if foo %}true{% endif %}', 'foo' => BooleanDrop.new(true))
+
+    assert_template_result('', '{% if foo %}true{% endif %}', 'foo' => BooleanDrop.new(false))
+    assert_template_result('', '{% if foo == true %}True{% endif %}', 'foo' => BooleanDrop.new(false))
+  end
+
+  def test_unless_tag_calls_to_liquid_value
+    assert_template_result('', '{% unless foo %}true{% endunless %}', 'foo' => BooleanDrop.new(true))
+  end
+
+  def test_case_tag_calls_to_liquid_value
+    assert_template_result('One', '{% case foo %}{% when 1 %}One{% endcase %}', 'foo' => IntegerDrop.new('1'))
+  end
+
   def test_simple_with_whitespaces
     template = Template.parse(%(  {{ test }}  ))
     assert_equal('  worked  ', template.render!('test' => 'worked'))
@@ -104,4 +131,8 @@ class VariableTest < Minitest::Test
   def test_dynamic_find_var
     assert_template_result('bar', '{{ [key] }}', 'key' => 'foo', 'foo' => 'bar')
   end
+
+  def test_raw_value_variable
+    assert_template_result('bar', '{{ [key] }}', 'key' => 'foo', 'foo' => 'bar')
+  end
 end

test/test_helper.rb

@@ -72,21 +72,21 @@ module Minitest
     end
 
     def with_global_filter(*globals)
-      original_global_filters = Liquid::StrainerFactory.instance_variable_get(:@global_filters)
-      Liquid::StrainerFactory.instance_variable_set(:@global_filters, [])
-      globals.each do |global|
-        Liquid::StrainerFactory.add_global_filter(global)
-      end
-
-      Liquid::StrainerFactory.send(:strainer_class_cache).clear
+      original_global_cache = Liquid::StrainerFactory::GlobalCache
+      Liquid::StrainerFactory.send(:remove_const, :GlobalCache)
+      Liquid::StrainerFactory.const_set(:GlobalCache, Class.new(Liquid::StrainerTemplate))
 
       globals.each do |global|
         Liquid::Template.register_filter(global)
       end
-      yield
-    ensure
       Liquid::StrainerFactory.send(:strainer_class_cache).clear
-      Liquid::StrainerFactory.instance_variable_set(:@global_filters, original_global_filters)
+      begin
+        yield
+      ensure
+        Liquid::StrainerFactory.send(:remove_const, :GlobalCache)
+        Liquid::StrainerFactory.const_set(:GlobalCache, original_global_cache)
+        Liquid::StrainerFactory.send(:strainer_class_cache).clear
+      end
     end
 
     def with_error_mode(mode)
@@ -119,6 +119,44 @@ class ThingWithToLiquid
   end
 end
 
+class IntegerDrop < Liquid::Drop
+  def initialize(value)
+    super()
+    @value = value.to_i
+  end
+
+  def ==(other)
+    @value == other
+  end
+
+  def to_s
+    @value.to_s
+  end
+
+  def to_liquid_value
+    @value
+  end
+end
+
+class BooleanDrop < Liquid::Drop
+  def initialize(value)
+    super()
+    @value = value
+  end
+
+  def ==(other)
+    @value == other
+  end
+
+  def to_liquid_value
+    @value
+  end
+
+  def to_s
+    @value ? "Yay" : "Nay"
+  end
+end
+
 class ErrorDrop < Liquid::Drop
   def standard_error
     raise Liquid::StandardError, 'standard error'

test/unit/condition_unit_test.rb

@@ -10,8 +10,8 @@ class ConditionUnitTest < Minitest::Test
   end
 
   def test_basic_condition
-    assert_equal(false, Condition.new(1, '==', 2).evaluate)
-    assert_equal(true,  Condition.new(1, '==', 1).evaluate)
+    assert_equal(false, Condition.new(1, '==', 2).evaluate(Context.new))
+    assert_equal(true,  Condition.new(1, '==', 1).evaluate(Context.new))
   end
 
   def test_default_operators_evalute_true
@@ -67,11 +67,11 @@ 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(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)
+    assert_nil(Condition.new({}, '>', 2).evaluate(Context.new))
+    assert_nil(Condition.new(2, '>', {}).evaluate(Context.new))
+    assert_equal(false, Condition.new({}, '==', 2).evaluate(Context.new))
+    assert_equal(true, Condition.new({ 'a' => 1 }, '==', 'a' => 1).evaluate(Context.new))
+    assert_equal(true, Condition.new({ 'a' => 2 }, 'contains', 'a').evaluate(Context.new))
   end
 
   def test_contains_works_on_arrays
@@ -106,30 +106,29 @@ class ConditionUnitTest < Minitest::Test
 
   def test_or_condition
     condition = Condition.new(1, '==', 2)
-
-    assert_equal(false, condition.evaluate)
+    assert_equal(false, condition.evaluate(Context.new))
 
     condition.or(Condition.new(2, '==', 1))
 
-    assert_equal(false, condition.evaluate)
+    assert_equal(false, condition.evaluate(Context.new))
 
     condition.or(Condition.new(1, '==', 1))
 
-    assert_equal(true, condition.evaluate)
+    assert_equal(true, condition.evaluate(Context.new))
   end
 
   def test_and_condition
     condition = Condition.new(1, '==', 1)
 
-    assert_equal(true, condition.evaluate)
+    assert_equal(true, condition.evaluate(Context.new))
 
     condition.and(Condition.new(2, '==', 2))
 
-    assert_equal(true, condition.evaluate)
+    assert_equal(true, condition.evaluate(Context.new))
 
     condition.and(Condition.new(2, '==', 1))
 
-    assert_equal(false, condition.evaluate)
+    assert_equal(false, condition.evaluate(Context.new))
   end
 
   def test_should_allow_custom_proc_operator
@@ -148,6 +147,20 @@ class ConditionUnitTest < Minitest::Test
     assert_evaluates_true(VariableLookup.new("one"), '==', VariableLookup.new("another"))
   end
 
+  def test_default_context_is_deprecated
+    if Gem::Version.new(Liquid::VERSION) >= Gem::Version.new('6.0.0')
+      flunk("Condition#evaluate without a context argument is to be removed")
+    end
+
+    _out, err = capture_io do
+      assert_equal(true, Condition.new(1, '==', 1).evaluate)
+    end
+
+    expected = "DEPRECATION WARNING: Condition#evaluate without a context argument is deprecated" \
+      " and will be removed from Liquid 6.0.0."
+    assert_includes(err.lines.map(&:strip), expected)
+  end
+
   private
 
   def assert_evaluates_true(left, op, right)

test/unit/parse_tree_visitor_test.rb

@@ -26,6 +26,13 @@ class ParseTreeVisitorTest < Minitest::Test
     )
   end
 
+  def test_echo
+    assert_equal(
+      ["test"],
+      visit(%({% echo test %}))
+    )
+  end
+
   def test_if_condition
     assert_equal(
       ["test"],
@@ -152,6 +159,13 @@ class ParseTreeVisitorTest < Minitest::Test
     )
   end
 
+  def test_for_range
+    assert_equal(
+      ["test"],
+      visit(%({% for x in (1..test) %}{% endfor %}))
+    )
+  end
+
   def test_tablerow_in
     assert_equal(
       ["test"],
@@ -222,6 +236,20 @@ class ParseTreeVisitorTest < Minitest::Test
     )
   end
 
+  def test_render_with
+    assert_equal(
+      ["test"],
+      visit(%({% render "hai" with test %}))
+    )
+  end
+
+  def test_render_for
+    assert_equal(
+      ["test"],
+      visit(%({% render "hai" for test %}))
+    )
+  end
+
   def test_preserve_tree_structure
     assert_equal(
       [[nil, [

test/unit/partial_cache_unit_test.rb

@@ -125,4 +125,35 @@ class PartialCacheUnitTest < Minitest::Test
     assert_equal('my partial body', partial.render)
     assert_equal(1, template_factory.count)
   end
+
+  def test_cache_state_is_shared_for_subcontexts
+    parse_context      = Liquid::ParseContext.new
+    shared_file_system = StubFileSystem.new(
+      'my_partial' => 'my shared value'
+    )
+    context = Liquid::Context.build(
+      registers: Liquid::Registers.new(
+        file_system: shared_file_system,
+      )
+    )
+    subcontext = context.new_isolated_subcontext
+
+    assert_equal(subcontext.registers[:cached_partials].object_id, context.registers[:cached_partials].object_id)
+
+    2.times do
+      Liquid::PartialCache.load(
+        'my_partial',
+        context: context,
+        parse_context: parse_context
+      )
+
+      Liquid::PartialCache.load(
+        'my_partial',
+        context: subcontext,
+        parse_context: parse_context
+      )
+    end
+
+    assert_equal(1, shared_file_system.file_read_count)
+  end
 end

test/unit/registers_unit_test.rb

@@ -2,11 +2,11 @@
 
 require 'test_helper'
 
-class StaticRegistersUnitTest < Minitest::Test
+class RegistersUnitTest < Minitest::Test
   include Liquid
 
   def test_set
-    static_register = StaticRegisters.new(a: 1, b: 2)
+    static_register = Registers.new(a: 1, b: 2)
     static_register[:b] = 22
     static_register[:c] = 33
 
@@ -16,13 +16,13 @@ class StaticRegistersUnitTest < Minitest::Test
   end
 
   def test_get_missing_key
-    static_register = StaticRegisters.new
+    static_register = Registers.new
 
     assert_nil(static_register[:missing])
   end
 
   def test_delete
-    static_register = StaticRegisters.new(a: 1, b: 2)
+    static_register = Registers.new(a: 1, b: 2)
     static_register[:b] = 22
     static_register[:c] = 33
 
@@ -37,7 +37,7 @@ class StaticRegistersUnitTest < Minitest::Test
   end
 
   def test_fetch
-    static_register = StaticRegisters.new(a: 1, b: 2)
+    static_register = Registers.new(a: 1, b: 2)
     static_register[:b] = 22
     static_register[:c] = 33
 
@@ -61,7 +61,7 @@ class StaticRegistersUnitTest < Minitest::Test
   end
 
   def test_key
-    static_register = StaticRegisters.new(a: 1, b: 2)
+    static_register = Registers.new(a: 1, b: 2)
     static_register[:b] = 22
     static_register[:c] = 33
 
@@ -72,7 +72,7 @@ class StaticRegistersUnitTest < Minitest::Test
   end
 
   def test_static_register_can_be_frozen
-    static_register = StaticRegisters.new(a: 1)
+    static_register = Registers.new(a: 1)
 
     static_register.static.freeze
 
@@ -94,14 +94,14 @@ class StaticRegistersUnitTest < Minitest::Test
   end
 
   def test_new_static_retains_static
-    static_register = StaticRegisters.new(a: 1, b: 2)
+    static_register = Registers.new(a: 1, b: 2)
     static_register[:b] = 22
     static_register[:c] = 33
 
-    new_static_register = StaticRegisters.new(static_register)
+    new_static_register = Registers.new(static_register)
     new_static_register[:b] = 222
 
-    newest_static_register = StaticRegisters.new(new_static_register)
+    newest_static_register = Registers.new(new_static_register)
     newest_static_register[:c] = 333
 
     assert_equal(1, static_register[:a])
@@ -118,11 +118,11 @@ class StaticRegistersUnitTest < Minitest::Test
   end
 
   def test_multiple_instances_are_unique
-    static_register_1 = StaticRegisters.new(a: 1, b: 2)
+    static_register_1 = Registers.new(a: 1, b: 2)
     static_register_1[:b] = 22
     static_register_1[:c] = 33
 
-    static_register_2 = StaticRegisters.new(a: 10, b: 20)
+    static_register_2 = Registers.new(a: 10, b: 20)
     static_register_2[:b] = 220
     static_register_2[:c] = 330
 
@@ -138,11 +138,11 @@ class StaticRegistersUnitTest < Minitest::Test
   end
 
   def test_initialization_reused_static_same_memory_object
-    static_register_1 = StaticRegisters.new(a: 1, b: 2)
+    static_register_1 = Registers.new(a: 1, b: 2)
     static_register_1[:b] = 22
     static_register_1[:c] = 33
 
-    static_register_2 = StaticRegisters.new(static_register_1)
+    static_register_2 = Registers.new(static_register_1)
 
     assert_equal(1, static_register_2[:a])
     assert_equal(2, static_register_2[:b])

test/unit/strainer_factory_unit_test.rb

@@ -52,7 +52,8 @@ class StrainerFactoryUnitTest < Minitest::Test
       /\ALiquid error: wrong number of arguments \((1 for 0|given 1, expected 0)\)\z/,
       exception.message
     )
-    assert_equal(exception.backtrace[0].split(':')[0], __FILE__)
+    source = AccessScopeFilters.instance_method(:public_filter).source_location
+    assert_equal(source.map(&:to_s), exception.backtrace[0].split(':')[0..1])
   end
 
   def test_strainer_only_invokes_public_filter_methods

test/unit/strainer_template_unit_test.rb

@@ -57,8 +57,8 @@ class StrainerTemplateUnitTest < Minitest::Test
   end
 
   def test_add_filter_does_not_raise_when_module_overrides_previously_registered_method
-    strainer = Context.new.strainer
     with_global_filter do
+      strainer = Context.new.strainer
       strainer.class.add_filter(PublicMethodOverrideFilter)
       assert(strainer.class.send(:filter_methods).include?('public_filter'))
     end