Add migrate tests for for tag

It transforms liquid code to equivalently parsed code, that doesn't depend
on lax parsing quirks.

Note that this transformation can hide the intent of the original code, so
it is best to review the changes, since removed syntax often would indicate
a bug in the original liquid code.

.github/probots.yml

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

.github/workflows/cla.yml

@@ -0,0 +1,22 @@
+name: Contributor License Agreement (CLA)
+
+on:
+  pull_request_target:
+    types: [opened, synchronize]
+  issue_comment:
+    types: [created]
+
+jobs:
+  cla:
+    runs-on: ubuntu-latest
+    if: |
+      (github.event.issue.pull_request 
+        && !github.event.issue.pull_request.merged_at
+        && contains(github.event.comment.body, 'signed')
+      ) 
+      || (github.event.pull_request && !github.event.pull_request.merged)
+    steps:
+      - uses: Shopify/shopify-cla-action@v1
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          cla-token: ${{ secrets.CLA_TOKEN }}

History.md

@@ -1,6 +1,6 @@
 # Liquid Change Log
 
-## 5.4.0 (unreleased)
+## 5.4.0 2022-07-29
 
 ### Breaking Changes
 * Drop support for end-of-life Ruby versions (2.5 and 2.6) (#1578) [Andy Waite]
@@ -11,6 +11,7 @@
 ### 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)

Rakefile

@@ -5,7 +5,7 @@ require 'rake/testtask'
 $LOAD_PATH.unshift(File.expand_path("../lib", __FILE__))
 require "liquid/version"
 
-task(default: [:test, :rubocop])
+task(default: [:test, "test:migrator_integration", :rubocop])
 
 desc('run test suite with default parser')
 Rake::TestTask.new(:base_test) do |t|
@@ -33,6 +33,23 @@ task :rubocop do
   end
 end
 
+namespace :test do
+  task :migrator_integration do
+    ENV['LIQUID_MIGRATOR'] = '1'
+    original_parse_mode = ENV['LIQUID_PARSER_MODE']
+    begin
+      Rake::Task['integration_test'].reenable
+      ["lax", "strict"].each do |parse_mode|
+        ENV['LIQUID_PARSER_MODE'] = parse_mode
+        Rake::Task['integration_test'].invoke
+        Rake::Task['integration_test'].reenable
+      end
+    ensure
+      ENV['LIQUID_PARSER_MODE'] = original_parse_mode
+    end
+  end
+end
+
 desc('runs test suite with both strict and lax parsers')
 task :test do
   ENV['LIQUID_PARSER_MODE'] = 'lax'

lib/liquid.rb

@@ -68,6 +68,7 @@ require 'liquid/parser_switching'
 require 'liquid/tag'
 require 'liquid/tag/disabler'
 require 'liquid/tag/disableable'
+require 'liquid/parse_context'
 require 'liquid/block'
 require 'liquid/block_body'
 require 'liquid/document'
@@ -81,7 +82,6 @@ require 'liquid/standardfilters'
 require 'liquid/condition'
 require 'liquid/utils'
 require 'liquid/tokenizer'
-require 'liquid/parse_context'
 require 'liquid/partial_cache'
 require 'liquid/usage'
 require 'liquid/registers'

lib/liquid/block.rb

@@ -60,6 +60,21 @@ module Liquid
       @block_delimiter ||= "end#{block_name}"
     end
 
+    def self.migrate_body(start_tag_name, tokenizer, parse_context)
+      new_body, unknown_tag = BlockBody.migrate(tokenizer, parse_context)
+
+      raise SyntaxError unless unknown_tag
+
+      block_delimiter = "end#{start_tag_name}"
+      if unknown_tag.tag_name == block_delimiter
+        new_body << unknown_tag.replaced_markup("") # markup was ignored on end tags
+        return [new_body, nil]
+      end
+
+      # handle the delimiter tag in the caller
+      [new_body, unknown_tag]
+    end
+
     private
 
     # @api public

lib/liquid/block_body.rb

@@ -30,6 +30,16 @@ module Liquid
       end
     end
 
+    def self.migrate(tokenizer, parse_context, &block)
+      parse_context.line_number = tokenizer.line_number
+
+      if tokenizer.for_liquid_tag
+        migrate_for_liquid_tag(tokenizer, parse_context, &block)
+      else
+        migrate_for_document(tokenizer, parse_context, &block)
+      end
+    end
+
     def freeze
       @nodelist.freeze
       super
@@ -60,6 +70,57 @@ module Liquid
       yield nil, nil
     end
 
+    class UnknownTagMigrator
+      attr_reader :tag_name, :markup
+
+      def initialize(match:, markup_capture_number:, tag_name:, markup:)
+        @match = match
+        @tag_name = tag_name
+        @markup = markup
+        @markup_capture_number = markup_capture_number
+      end
+
+      def original_tag_string
+        @match[0]
+      end
+
+      def replaced_markup(new_markup)
+        Utils.match_capture_replace(@match, @markup_capture_number, new_markup)
+      end
+    end
+
+    private_class_method def self.migrate_for_liquid_tag(tokenizer, parse_context)
+      result = +""
+      while (token = tokenizer.shift)
+        token += "\n" if tokenizer.more?
+        if token.empty? || token.match?(WhitespaceOrNothing)
+          result << token
+        else
+          # modified version of LiquidTagToken with following changes:
+          # * TagName is optional, to continue supporting its absence in the comment tag
+          # * trailing spaces is allowed to support the newline appended above and so the tag
+          #   migrate method doesn't have to handle trailing whitespace
+          match = token.match(/\A\s*(#{TagName})?\s*(.*?)\s*\z/o)
+          tag_name = match[1]
+          markup   = match[2]
+          unless (tag = Template.tags[tag_name])
+            # delegate handling of unknown tags to the caller, where a block tag may treat
+            # it as an end tag or body delimiter.
+            unknown_tag = UnknownTagMigrator.new(
+              match: match, markup_capture_number: 2, tag_name: tag_name, markup: markup
+            )
+            return [result, unknown_tag]
+          end
+          new_markup, new_tag_body = tag.migrate(tag_name, markup, tokenizer, parse_context)
+          result << Utils.match_capture_replace(match, 2, new_markup)
+          result << new_tag_body.to_s
+        end
+        parse_context.line_number = tokenizer.line_number
+      end
+
+      [result, nil]
+    end
+
     # @api private
     def self.unknown_tag_in_liquid_tag(tag, parse_context)
       Block.raise_unknown_tag(tag, 'liquid', '%}', parse_context)
@@ -109,14 +170,31 @@ module Liquid
       end
     end
 
-    private def parse_for_document(tokenizer, parse_context)
+    private_class_method def self.migrate_liquid_tag(markup, parse_context)
+      liquid_tag_tokenizer = parse_context.new_tokenizer(
+        markup, start_line_number: parse_context.line_number, for_liquid_tag: true
+      )
+      result, unknown_tag = migrate_for_liquid_tag(liquid_tag_tokenizer, parse_context)
+      raise SyntaxError if unknown_tag
+      result
+    end
+
+    private def handle_invalid_tag_token(token, parse_context)
+      if token.end_with?('%}')
+        yield token, token
+      else
+        BlockBody.raise_missing_tag_terminator(token, parse_context)
+      end
+    end
+
+    private def parse_for_document(tokenizer, parse_context, &block)
       while (token = tokenizer.shift)
         next if token.empty?
         case
         when token.start_with?(TAGSTART)
           whitespace_handler(token, parse_context)
           unless token =~ FullToken
-            BlockBody.raise_missing_tag_terminator(token, parse_context)
+            return handle_invalid_tag_token(token, parse_context, &block)
           end
           tag_name = Regexp.last_match(2)
           markup   = Regexp.last_match(4)
@@ -158,6 +236,58 @@ module Liquid
       yield nil, nil
     end
 
+    private_class_method def self.migrate_for_document(tokenizer, parse_context, &block)
+      result = +""
+      while (token = tokenizer.shift)
+        next if token.empty?
+
+        case
+        when token.start_with?(TAGSTART)
+          raise SyntaxError unless token.end_with?('%}')
+          # modified FullToken regex with optional tag name, to allow its absence in a comment tag
+          match = token.match(/\A#{TagStart}#{WhitespaceControl}?(\s*)(#{TagName})?(\s*)(.*?)#{WhitespaceControl}?#{TagEnd}\z/om)
+          tag_name = match[2]
+          markup   = match[4]
+
+          if parse_context.line_number
+            # newlines inside the tag should increase the line number,
+            # particularly important for multiline {% liquid %} tags
+            parse_context.line_number += Regexp.last_match(1).count("\n") + Regexp.last_match(3).count("\n")
+          end
+
+          if tag_name == 'liquid'
+            new_markup = Utils.migrate_stripped(markup) do |stripped_markup|
+              migrate_liquid_tag(stripped_markup, parse_context)
+            end
+            result << Utils.match_capture_replace(match, 4, new_markup)
+            next
+          end
+
+          unless (tag = Template.tags[tag_name])
+            # delegate handling of unknown tags to the caller, where a block tag may treat
+            # it as an end tag or body delimiter.
+            unknown_tag = UnknownTagMigrator.new(
+              match: match, markup_capture_number: 4, tag_name: tag_name, markup: markup
+            )
+            return [result, unknown_tag]
+          end
+          new_tag_body = nil
+          new_markup = Utils.migrate_stripped(markup) do |stripped_markup|
+            new_stripped_markup, new_tag_body = tag.migrate(tag_name, stripped_markup, tokenizer, parse_context)
+            new_stripped_markup
+          end
+          result << Utils.match_capture_replace(match, 4, new_markup) << new_tag_body.to_s
+        when token.start_with?(VARSTART)
+          result << migrate_variable(token, parse_context)
+        else
+          result << token
+        end
+        parse_context.line_number = tokenizer.line_number
+      end
+
+      [result, nil]
+    end
+
     def whitespace_handler(token, parse_context)
       if token[2] == WhitespaceControl
         previous_token = @nodelist.last
@@ -238,6 +368,17 @@ module Liquid
       BlockBody.raise_missing_variable_terminator(token, parse_context)
     end
 
+    private_class_method def self.migrate_variable(token, parse_context)
+      match = token.match(ContentOfVariable)
+      if match
+        new_markup = Utils.migrate_stripped(match[1]) do |markup|
+          Variable.migrate(markup, parse_context)
+        end
+        return Utils.match_capture_replace(match, 1, new_markup)
+      end
+      BlockBody.raise_missing_variable_terminator(token, parse_context)
+    end
+
     # @deprecated Use {.raise_missing_tag_terminator} instead
     def raise_missing_tag_terminator(token, parse_context)
       BlockBody.raise_missing_tag_terminator(token, parse_context)

lib/liquid/context.rb

@@ -26,7 +26,7 @@ module Liquid
       @environments = [environments]
       @environments.flatten!
 
-      @static_environments = [static_environments].flat_map(&:freeze).freeze
+      @static_environments = [static_environments].flatten(1).freeze
       @scopes              = [(outer_scope || {})]
       @registers           = registers.is_a?(Registers) ? registers : Registers.new(registers)
       @errors              = []

lib/liquid/document.rb

@@ -28,6 +28,16 @@ module Liquid
       raise
     end
 
+    def self.migrate(tokenizer, parse_context)
+      new_body, unknown_tag = BlockBody.migrate(tokenizer, parse_context)
+      raise SyntaxError if unknown_tag
+
+      new_body
+    rescue SyntaxError => e
+      e.line_number ||= parse_context.line_number
+      raise
+    end
+
     def unknown_tag(tag, _markup, _tokenizer)
       case tag
       when 'else', 'end'

lib/liquid/expression.rb

@@ -41,5 +41,36 @@ module Liquid
         end
       end
     end
+
+    def self.lax_migrate(markup)
+      Utils.migrate_stripped(markup) do |markup|
+        raise ArgumentError, "unexpected empty expression" if markup.empty?
+
+        if (markup.start_with?('"') && markup.end_with?('"')) ||
+           (markup.start_with?("'") && markup.end_with?("'"))
+          markup
+        else
+          case markup
+          when INTEGERS_REGEX
+            markup
+          when RANGES_REGEX
+            match = Regexp.last_match
+            new_start, new_end = RangeLookup.lax_migrate(match[1], match[2])
+            Utils.match_captures_replace(match, 1 => new_start, 2 => new_end)
+          when FLOATS_REGEX
+            # lax parser allowed multiple periods, but the second period and following characters were ignored
+            new_markup = markup.slice(/\A(-?\d+\.\d*)/)
+            new_markup << "0" if new_markup.end_with?(".")
+            new_markup
+          else
+            if LITERALS.key?(markup)
+              markup
+            else
+              VariableLookup.lax_migrate(markup)
+            end
+          end
+        end
+      end
+    end
   end
 end

lib/liquid/forloop_drop.rb

@@ -5,7 +5,7 @@ module Liquid
   # @liquid_type object
   # @liquid_name forloop
   # @liquid_summary
-  #   Information about a parent [`for` loop](/api/liquid/tags#for).
+  #   Information about a parent [`for` loop](/api/liquid/tags/for).
   class ForloopDrop < Drop
     def initialize(name, length, parentloop)
       @name       = name
@@ -30,10 +30,7 @@ module Liquid
     # @liquid_return [forloop]
     attr_reader :parentloop
 
-    def name
-      Usage.increment('forloop_drop_name')
-      @name
-    end
+    attr_reader :name
 
     # @liquid_public_docs
     # @liquid_summary

lib/liquid/lexer.rb

@@ -18,6 +18,7 @@ module Liquid
     IDENTIFIER            = /[a-zA-Z_][\w-]*\??/
     SINGLE_STRING_LITERAL = /'[^\']*'/
     DOUBLE_STRING_LITERAL = /"[^\"]*"/
+    STRING_LITERAL        = Regexp.union(SINGLE_STRING_LITERAL, DOUBLE_STRING_LITERAL)
     NUMBER_LITERAL        = /-?\d+(\.\d+)?/
     DOTDOT                = /\.\./
     COMPARISON_OPERATOR   = /==|!=|<>|<=?|>=?|contains(?=\s)/
@@ -35,9 +36,7 @@ module Liquid
         break if @ss.eos?
         tok      = if (t = @ss.scan(COMPARISON_OPERATOR))
           [:comparison, t]
-        elsif (t = @ss.scan(SINGLE_STRING_LITERAL))
-          [:string, t]
-        elsif (t = @ss.scan(DOUBLE_STRING_LITERAL))
+        elsif (t = @ss.scan(STRING_LITERAL))
           [:string, t]
         elsif (t = @ss.scan(NUMBER_LITERAL))
           [:number, t]

lib/liquid/parse_context.rb

@@ -5,6 +5,9 @@ module Liquid
     attr_accessor :locale, :line_number, :trim_whitespace, :depth
     attr_reader :partial, :warnings, :error_mode
 
+    # @api private
+    attr_writer :error_mode
+
     def initialize(options = {})
       @template_options = options ? options.dup : {}
 

lib/liquid/parser_switching.rb

@@ -2,6 +2,30 @@
 
 module Liquid
   module ParserSwitching
+    module ClassMethods
+      def migrate_with_selected_parser(tag_name, markup, tokenizer, parse_context)
+        case parse_context.error_mode
+        when :strict then strict_migrate(tag_name, markup, tokenizer, parse_context)
+        when :lax    then lax_migrate(tag_name, markup, tokenizer, parse_context)
+        when :warn
+          begin
+            parse_context.error_mode = :strict
+            begin
+              # Use exception side effect to conditionally branch to lax migration
+              parse(tag_name, markup, tokenizer, parse_context)
+            ensure
+              parse_context.error_mode = :warn
+            end
+
+            strict_migrate(tag_name, markup, tokenizer, parse_context)
+          rescue SyntaxError => e
+            parse_context.warnings << e
+            lax_migrate(tag_name, markup, tokenizer, parse_context)
+          end
+        end
+      end
+    end
+
     def strict_parse_with_error_mode_fallback(markup)
       strict_parse_with_error_context(markup)
     rescue SyntaxError => e

lib/liquid/range_lookup.rb

@@ -8,7 +8,48 @@ module Liquid
       if start_obj.respond_to?(:evaluate) || end_obj.respond_to?(:evaluate)
         new(start_obj, end_obj)
       else
-        start_obj.to_i..end_obj.to_i
+        begin
+          start_obj.to_i..end_obj.to_i
+        rescue NoMethodError
+          invalid_expr = start_markup unless start_obj.respond_to?(:to_i)
+          invalid_expr ||= end_markup unless end_obj.respond_to?(:to_i)
+          if invalid_expr
+            raise Liquid::SyntaxError, "Invalid expression type '#{invalid_expr}' in range expression"
+          end
+
+          raise
+        end
+      end
+    end
+
+    def self.lax_migrate(start_markup, end_markup)
+      new_start = Expression.lax_migrate(start_markup)
+      new_end = Expression.lax_migrate(end_markup)
+
+      # cast literals
+      start_obj = Expression.parse(new_start)
+      end_obj   = Expression.parse(new_end)
+      if start_obj.respond_to?(:evaluate) || end_obj.respond_to?(:evaluate)
+        new_start = lax_migrate_range_expression(new_start, start_obj)
+        new_end = lax_migrate_range_expression(new_end, end_obj)
+      else
+        new_start = start_obj.to_i.to_s unless start_obj.is_a?(Integer)
+        new_end = end_obj.to_i.to_s unless end_obj.is_a?(Integer)
+      end
+
+      [new_start, new_end]
+    end
+
+    def self.lax_migrate_range_expression(markup, expression)
+      return markup if expression.respond_to?(:evaluate)
+
+      case expression
+      when Integer
+        markup
+      when NilClass, String
+        expression.to_i.to_s
+      else
+        Utils.to_integer(input).to_s
       end
     end
 

lib/liquid/standardfilters.rb

@@ -6,7 +6,14 @@ require 'bigdecimal'
 
 module Liquid
   module StandardFilters
-    MAX_INT = (1 << 31) - 1
+    MAX_I32 = (1 << 31) - 1
+    private_constant :MAX_I32
+
+    MIN_I64 = -(1 << 63)
+    MAX_I64 = (1 << 63) - 1
+    I64_RANGE = MIN_I64..MAX_I64
+    private_constant :MIN_I64, :MAX_I64, :I64_RANGE
+
     HTML_ESCAPE = {
       '&' => '&amp;',
       '>' => '&gt;',
@@ -73,7 +80,7 @@ module Liquid
     # @liquid_type filter
     # @liquid_category string
     # @liquid_summary
-    #   Escapes a string.
+    #   Escapes special characters in HTML, such as `<>`, `'`, and `&`, and converts characters into escape sequences. The filter doesn't effect characters within the string that don’t have a corresponding escape sequence.".
     # @liquid_syntax string | escape
     # @liquid_return [string]
     def escape(input)
@@ -186,10 +193,19 @@ module Liquid
       offset = Utils.to_integer(offset)
       length = length ? Utils.to_integer(length) : 1
 
-      if input.is_a?(Array)
-        input.slice(offset, length) || []
-      else
-        input.to_s.slice(offset, length) || ''
+      begin
+        if input.is_a?(Array)
+          input.slice(offset, length) || []
+        else
+          input.to_s.slice(offset, length) || ''
+        end
+      rescue RangeError
+        if I64_RANGE.cover?(length) && I64_RANGE.cover?(offset)
+          raise # unexpected error
+        end
+        offset = offset.clamp(I64_RANGE)
+        length = length.clamp(I64_RANGE)
+        retry
       end
     end
 
@@ -239,9 +255,9 @@ module Liquid
       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"
+        # integer too big for String#split, but we can semantically assume no truncation is needed
+        return input if words + 1 > MAX_I32
+        raise # unexpected error
       end
       return input if wordlist.length <= words
 
@@ -358,7 +374,11 @@ module Liquid
     # @liquid_type filter
     # @liquid_category array
     # @liquid_summary
-    #   Sorts the items in an array in case-insensitive alphabetical, or numerical, order.
+    #   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)
@@ -595,7 +615,7 @@ module Liquid
     # @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).
+    #   > [`uniq` filter](/api/liquid/filters/uniq).
     # @liquid_syntax array | concat: array
     # @liquid_return [array[untyped]]
     def concat(input, array)

lib/liquid/strainer_factory.rb

@@ -14,6 +14,10 @@ module Liquid
       strainer_from_cache(filters).new(context)
     end
 
+    def global_filter_names
+      GlobalCache.filter_method_names
+    end
+
     GlobalCache = Class.new(StrainerTemplate)
 
     private

lib/liquid/strainer_template.rb

@@ -36,6 +36,10 @@ module Liquid
         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

@@ -5,7 +5,7 @@ module Liquid
   # @liquid_type object
   # @liquid_name tablerowloop
   # @liquid_summary
-  #   Information about a parent [`tablerow` loop](/api/liquid/tags#tablerow).
+  #   Information about a parent [`tablerow` loop](/api/liquid/tags/tablerow).
   class TablerowloopDrop < Drop
     def initialize(length, cols)
       @length = length

lib/liquid/tag.rb

@@ -7,6 +7,8 @@ module Liquid
     include ParserSwitching
 
     class << self
+      include ParserSwitching::ClassMethods
+
       def parse(tag_name, markup, tokenizer, parse_context)
         tag = new(tag_name, markup, parse_context)
         tag.parse(tokenizer)
@@ -14,12 +16,18 @@ module Liquid
       end
 
       def disable_tags(*tag_names)
-        @disabled_tags ||= []
-        @disabled_tags.concat(tag_names)
+        tag_names += disabled_tags
+        define_singleton_method(:disabled_tags) { tag_names }
         prepend(Disabler)
       end
 
       private :new
+
+      protected
+
+      def disabled_tags
+        []
+      end
     end
 
     def initialize(tag_name, markup, parse_context)

lib/liquid/tag/disabler.rb

@@ -3,14 +3,6 @@
 module Liquid
   class Tag
     module Disabler
-      module ClassMethods
-        attr_reader :disabled_tags
-      end
-
-      def self.prepended(base)
-        base.extend(ClassMethods)
-      end
-
       def render_to_output_buffer(context, output)
         context.with_disabled_tags(self.class.disabled_tags) do
           super

lib/liquid/tags/assign.rb

@@ -21,6 +21,18 @@ module Liquid
       raise Liquid::SyntaxError, parse_context.locale.t('errors.syntax.assign')
     end
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      match = markup.match(Syntax)
+      new_variable_markup = Variable.migrate(match[2], parse_context)
+      new_markup = Utils.match_captures_replace(match, 2 => new_variable_markup)
+
+      # replace scanned over characters with a space to ensure there is a space
+      # to separate the tag name and the variable name
+      new_markup.prepend(" ") if match.begin(0) > 0
+
+      new_markup
+    end
+
     attr_reader :to, :from
 
     def initialize(tag_name, markup, parse_context)

lib/liquid/tags/break.rb

@@ -15,12 +15,16 @@ module Liquid
   # @liquid_category iteration
   # @liquid_name break
   # @liquid_summary
-  #   Stops a [`for` loop](/api/liquid/tags#for) from iterating.
+  #   Stops a [`for` loop](/api/liquid/tags/for) from iterating.
   # @liquid_syntax
   #   {% break %}
   class Break < Tag
     INTERRUPT = BreakInterrupt.new.freeze
 
+    def self.migrate(_tag_name, _markup, _tokenizer, _parse_context)
+      "" # markup was ignored
+    end
+
     def render_to_output_buffer(context, output)
       context.push_interrupt(INTERRUPT)
       output

lib/liquid/tags/capture.rb

@@ -18,6 +18,21 @@ module Liquid
   class Capture < Block
     Syntax = /(#{VariableSignature}+)/o
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      match = markup.match(Syntax)
+
+      new_markup = match[1]
+
+      # replace scanned over characters with a space to ensure there is a space
+      # to separate the tag name and the variable name
+      new_markup.prepend(" ") if match.begin(0) > 0
+
+      new_body, unknown_tag = migrate_body(tag_name, tokenizer, parse_context)
+      raise SyntaxError if unknown_tag
+
+      [new_markup, new_body]
+    end
+
     def initialize(tag_name, markup, options)
       super
       if markup =~ Syntax

lib/liquid/tags/case.rb

@@ -28,6 +28,20 @@ module Liquid
 
     attr_reader :blocks, :left
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      match = markup.match(/\s*#{Syntax}\s*/o) || raise(SyntaxError)
+
+      new_expression = Expression.lax_migrate(match[1])
+      new_markup = Utils.match_captures_replace(match, { 1 => new_expression })
+
+      # replace scanned over characters with a space to ensure there is a space
+      # to separate the tag name and the variable name
+      new_markup.prepend(" ") if match.begin(0) > 0
+
+      new_body = migrate_body(tag_name, tokenizer, parse_context)
+      [new_markup, new_body]
+    end
+
     def initialize(tag_name, markup, options)
       super
       @blocks = []
@@ -39,6 +53,37 @@ module Liquid
       end
     end
 
+    def self.migrate_body(start_tag_name, tokenizer, parse_context)
+      result = +""
+
+      # body before first `when` delimiter tag is ignored
+      unused_body, delimiter_tag = super(start_tag_name, tokenizer, parse_context)
+      unless delimiter_tag
+        raise NotImplementedError, "TODO: migrate `case` tag with no `when` or `else` tags"
+      end
+
+      result << Utils.migrate_stripped(unused_body) { "" } # just keep whitespace (e.g. newline and indent)
+
+      while delimiter_tag
+        break unless delimiter_tag
+
+        case delimiter_tag.tag_name
+        when "when"
+          new_markup = migrate_when_markup(delimiter_tag.markup)
+          result << delimiter_tag.replaced_markup(new_markup)
+        when "else"
+          result << delimiter_tag.original_tag_string
+        else
+          raise SyntaxError
+        end
+
+        new_body, delimiter_tag = super(start_tag_name, tokenizer, parse_context)
+        result << new_body
+      end
+
+      result
+    end
+
     def parse(tokens)
       body = case_body = new_body
       body = @blocks.last.attachment while parse_body(body, tokens)
@@ -91,6 +136,25 @@ module Liquid
 
     private
 
+    private_class_method def self.migrate_when_markup(unstripped_markup)
+      Utils.migrate_stripped(unstripped_markup) do |markup|
+        match = markup.match(WhenSyntax) || raise(SyntaxError)
+
+        replacements = { 1 => Expression.lax_migrate(match[1]) }
+        if (right = match[2])
+          replacements[2] = migrate_when_markup(right)
+        end
+
+        new_markup = Utils.match_captures_replace(match, replacements)
+
+        # replace scanned over characters with a space to ensure there is a space
+        # to separate the tag name and the variable name
+        new_markup.prepend(" ") if match.begin(0) > 0
+
+        new_markup
+      end
+    end
+
     def record_when_condition(markup)
       body = new_body
 

lib/liquid/tags/comment.rb

@@ -8,13 +8,31 @@ module Liquid
   # @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.
+  #   Any text inside `comment` tags won't be output, and any Liquid code will be parsed, but not executed.
   # @liquid_syntax
   #   {% comment %}
   #     content
   #   {% endcomment %}
   # @liquid_syntax_keyword content The content of the comment.
   class Comment < Block
+    def self.migrate(tag_name, _markup, tokenizer, parse_context)
+      new_markup = "" # markup was ignored
+      new_body = migrate_body(tag_name, tokenizer, parse_context)
+      [new_markup, new_body]
+    end
+
+    def self.migrate_body(start_tag_name, tokenizer, parse_context)
+      result = +""
+      loop do
+        new_body, delimiter_tag = super(start_tag_name, tokenizer, parse_context)
+        result << new_body
+        break unless delimiter_tag
+
+        result << delimiter_tag.original_tag_string # unknown tags allowed
+      end
+      result
+    end
+
     def render_to_output_buffer(_context, output)
       output
     end

lib/liquid/tags/continue.rb

@@ -6,12 +6,16 @@ module Liquid
   # @liquid_category iteration
   # @liquid_name continue
   # @liquid_summary
-  #   Causes a [`for` loop](/api/liquid/tags#for) to skip to the next iteration.
+  #   Causes a [`for` loop](/api/liquid/tags/for) to skip to the next iteration.
   # @liquid_syntax
   #   {% continue %}
   class Continue < Tag
     INTERRUPT = ContinueInterrupt.new.freeze
 
+    def self.migrate(_tag_name, _markup, _tokenizer, _parse_context)
+      "" # markup was ignored
+    end
+
     def render_to_output_buffer(context, output)
       context.push_interrupt(INTERRUPT)
       output

lib/liquid/tags/cycle.rb

@@ -6,7 +6,7 @@ module Liquid
   # @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).
+  #   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.
   #
@@ -18,8 +18,43 @@ module Liquid
     SimpleSyntax = /\A#{QuotedFragment}+/o
     NamedSyntax  = /\A(#{QuotedFragment})\s*\:\s*(.*)/om
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      new_markup = case markup
+      when NamedSyntax
+        match = Regexp.last_match
+
+        new_name_syntax = Expression.lax_migrate(match[1])
+        new_variables_markup = migrate_variables_from_string(match[2])
+
+        Utils.match_captures_replace(match, 1 => new_name_syntax, 2 => new_variables_markup)
+      when SimpleSyntax
+        match = Regexp.last_match
+        migrate_variables_from_string(markup)
+      else
+        raise SyntaxError
+      end
+
+      # replace scanned over characters with a space to ensure there is a space
+      # to separate the tag name and the variable name
+      new_markup.prepend(" ") if match.begin(0) > 0
+
+      new_markup
+    end
+
+    def self.migrate_variables_from_string(markup)
+      markup.split(',').collect do |var|
+        match = var.match(/\s*(#{QuotedFragment})\s*/o)
+        if match
+          Utils.match_captures_replace(match, 1 => Expression.lax_migrate(match[1]))
+        end
+      end.compact.join(",")
+    end
+
     attr_reader :variables
 
+    # @api private
+    attr_reader :name
+
     def initialize(tag_name, markup, options)
       super
       case markup

lib/liquid/tags/decrement.rb

@@ -12,22 +12,29 @@ module Liquid
   #   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
+  #   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
+    attr_reader :variable_name
+
+    def self.migrate(_tag_name, markup, _tokenizer, _parse_context)
+      markup # no characters ignored, it just uses anything for the variable name
+    end
+
     def initialize(tag_name, markup, options)
       super
-      @variable = markup.strip
+      @variable_name = markup.strip
     end
 
     def render_to_output_buffer(context, output)
-      value = context.environments.first[@variable] ||= 0
+      counter_environment = context.environments.first
+      value = counter_environment[@variable_name] || 0
       value -= 1
-      context.environments.first[@variable] = value
+      counter_environment[@variable_name] = value
       output << value.to_s
       output
     end

lib/liquid/tags/echo.rb

@@ -9,7 +9,7 @@ module Liquid
   #   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).
+  #   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.
@@ -21,6 +21,10 @@ module Liquid
   class Echo < Tag
     attr_reader :variable
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      Variable.migrate(markup, parse_context)
+    end
+
     def initialize(tag_name, markup, parse_context)
       super
       @variable = Variable.new(markup, parse_context)

lib/liquid/tags/for.rb

@@ -9,10 +9,10 @@ module Liquid
   #   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.
+  #   [`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.
+  #   > Every `for` loop has an associated [`forloop` object](/api/liquid/objects/forloop) with information about the loop.
   # @liquid_syntax
   #   {% for variable in array %}
   #     expression
@@ -25,10 +25,16 @@ module Liquid
   # @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
+    Syntax = /\A(#{VariableSegment}+)\s+in\s+(#{QuotedFragment}+)(\s*reversed)?/o
 
     attr_reader :collection_name, :variable_name, :limit, :from
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      new_markup = migrate_with_selected_parser(tag_name, markup, tokenizer, parse_context)
+      new_body = migrate_body(tag_name, tokenizer, parse_context)
+      [new_markup, new_body]
+    end
+
     def initialize(tag_name, markup, options)
       super
       @from = @limit = nil
@@ -53,6 +59,27 @@ module Liquid
       @else_block ? [@for_block, @else_block] : [@for_block]
     end
 
+    def self.migrate_body(start_tag_name, tokenizer, parse_context)
+      result = +""
+
+      new_body, delimiter_tag = super(start_tag_name, tokenizer, parse_context)
+      result << new_body
+
+      else_tag = delimiter_tag
+      else_body = nil
+      while delimiter_tag
+        raise SyntaxError unless delimiter_tag.tag_name == 'else'
+        else_tag = delimiter_tag
+        else_body, delimiter_tag = super(start_tag_name, tokenizer, parse_context)
+      end
+      if else_tag
+        result << else_tag.replaced_markup("") # markup was ignored in else tags
+        result << else_body
+      end
+
+      result
+    end
+
     def unknown_tag(tag, markup, tokens)
       return super unless tag == 'else'
       @else_block = new_body
@@ -72,6 +99,13 @@ module Liquid
 
     protected
 
+    private_class_method def self.lax_migrate(tag_name, markup, tokenizer, parse_context)
+      match = markup.match(Syntax) || raise(SyntaxError)
+      new_collection_name = Expression.lax_migrate(match[2])
+      new_markup = Utils.match_captures_replace(match, { 2 => new_collection_name }.compact)
+      new_markup << Utils.migrate_tag_attributes(markup)
+    end
+
     def lax_parse(markup)
       if markup =~ Syntax
         @variable_name   = Regexp.last_match(1)
@@ -87,6 +121,10 @@ module Liquid
       end
     end
 
+    private_class_method def self.strict_migrate(tag_name, markup, tokenizer, parse_context)
+      markup
+    end
+
     def strict_parse(markup)
       p = Parser.new(markup)
       @variable_name = p.consume(:id)
@@ -98,11 +136,12 @@ module Liquid
       @name     = "#{@variable_name}-#{collection_name}"
       @reversed = p.id?('reversed')
 
-      while p.look(:id) && p.look(:colon, 1)
+      while p.look(:comma) || p.look(:id)
+        p.consume?(:comma)
         unless (attribute = p.id?('limit') || p.id?('offset'))
           raise SyntaxError, options[:locale].t("errors.syntax.for_invalid_attribute")
         end
-        p.consume
+        p.consume(:colon)
         set_attribute(attribute, p.expression)
       end
       p.consume(:end_of_string)
@@ -177,7 +216,6 @@ module Liquid
       case key
       when 'offset'
         @from = if expr == 'continue'
-          Usage.increment('for_offset_continue')
           :continue
         else
           parse_expression(expr)

lib/liquid/tags/if.rb

@@ -20,6 +20,39 @@ module Liquid
 
     attr_reader :blocks
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      new_markup = migrate_with_selected_parser(tag_name, markup, tokenizer, parse_context)
+      new_body = migrate_body(tag_name, tokenizer, parse_context)
+      [new_markup, new_body]
+    end
+
+    def self.migrate_body(start_tag_name, tokenizer, parse_context)
+      result = +""
+
+      loop do
+        new_body, delimiter_tag = super(start_tag_name, tokenizer, parse_context)
+        result << new_body
+
+        break unless delimiter_tag
+
+        case delimiter_tag.tag_name
+        when "else"
+          result << delimiter_tag.replaced_markup("") # markup was ignored on else tags
+        when "elsif"
+          new_markup = migrate_with_selected_parser(delimiter_tag.tag_name, delimiter_tag.markup, tokenizer, parse_context)
+          result << delimiter_tag.replaced_markup(new_markup)
+        else
+          raise SyntaxError
+        end
+      end
+
+      result
+    end
+
+    private_class_method def self.strict_migrate(tag_name, markup, tokenizer, parse_context)
+      markup
+    end
+
     def initialize(tag_name, markup, options)
       super
       @blocks = []
@@ -81,6 +114,10 @@ module Liquid
       Condition.parse_expression(parse_context, markup)
     end
 
+    private_class_method def self.lax_migrate_expression(markup)
+      Expression.lax_migrate(markup)
+    end
+
     def lax_parse(markup)
       expressions = markup.scan(ExpressionsAndOperators)
       raise SyntaxError, options[:locale].t("errors.syntax.if") unless expressions.pop =~ Syntax
@@ -101,6 +138,40 @@ module Liquid
       condition
     end
 
+    private_class_method def self.lax_migrate(tag_name, markup, tokenizer, parse_context)
+      expressions = markup.scan(ExpressionsAndOperators)
+
+      new_markup = lax_migrate_condition(expressions.pop)
+      until expressions.empty?
+        operator = expressions.pop
+        new_left_markup = lax_migrate_condition(expressions.pop)
+        new_markup = new_left_markup << operator << new_markup
+      end
+
+      new_markup
+    end
+
+    private_class_method def self.lax_migrate_condition(markup)
+      Utils.migrate_stripped(markup) do |markup|
+        match = markup.match(Syntax)
+        left = lax_migrate_expression(match[1])
+        op = match[2]
+        right_capture = match[3]
+        if op
+          right = lax_migrate_expression(right_capture) if right_capture
+        elsif right_capture
+          right = "" # remove right capture, since it is ignored with no operator
+        end
+        new_markup = Utils.match_captures_replace(match, { 1 => left, 2 => op, 3 => right }.compact)
+        new_markup.prepend(' ') if match.begin(0) > 0
+        new_markup << ' ' if match.end(0) < markup.length
+        if op && !right # missing right operand missing
+          new_markup << " nil" # replace with nil, which it was semantically treated as
+        end
+        new_markup
+      end
+    end
+
     def strict_parse(markup)
       p = Parser.new(markup)
       condition = parse_binary_comparisons(p)

lib/liquid/tags/ifchanged.rb

@@ -2,6 +2,15 @@
 
 module Liquid
   class Ifchanged < Block
+    def self.migrate(tag_name, _markup, tokenizer, parse_context)
+      new_markup = "" # markup was ignored
+
+      new_body, unknown_tag = migrate_body(tag_name, tokenizer, parse_context)
+      raise SyntaxError if unknown_tag
+
+      [new_markup, new_body]
+    end
+
     def render_to_output_buffer(context, output)
       block_output = +''
       super(context, block_output)

lib/liquid/tags/include.rb

@@ -8,7 +8,7 @@ module Liquid
   # @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
+  #   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' %}
@@ -16,7 +16,7 @@ module Liquid
   # @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).
+  #   The `include` tag has been replaced by [`render`](/api/liquid/tags/render).
   class Include < Tag
     prepend Tag::Disableable
 
@@ -25,6 +25,22 @@ module Liquid
 
     attr_reader :template_name_expr, :variable_name_expr, :attributes
 
+    def self.migrate(_tag_name, markup, _tokenizer, parse_context)
+      match = markup.match(SYNTAX) || raise(SyntaxError)
+
+      template_name = Expression.lax_migrate(match[1])
+      variable_name = Expression.lax_migrate(match[3]) if match[3]
+
+      new_markup = Utils.match_captures_replace(match, { 1 => template_name, 3 => variable_name }.compact)
+      new_markup << Utils.migrate_tag_attributes(markup)
+
+      # replace scanned over characters with a space to ensure there is a space
+      # to separate the tag name and the variable name
+      new_markup.prepend(" ") if match.begin(0) > 0
+
+      new_markup
+    end
+
     def initialize(tag_name, markup, options)
       super
 
@@ -52,7 +68,7 @@ module Liquid
 
     def render_to_output_buffer(context, output)
       template_name = context.evaluate(@template_name_expr)
-      raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name
+      raise ArgumentError, options[:locale].t("errors.argument.include") unless template_name.is_a?(String)
 
       partial = PartialCache.load(
         template_name,

lib/liquid/tags/increment.rb

@@ -12,21 +12,28 @@ module Liquid
   #   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
+  #   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
+    attr_reader :variable_name
+
+    def self.migrate(_tag_name, markup, _tokenizer, _parse_context)
+      markup # no characters ignored, it just uses anything for the variable name
+    end
+
     def initialize(tag_name, markup, options)
       super
-      @variable = markup.strip
+      @variable_name = markup.strip
     end
 
     def render_to_output_buffer(context, output)
-      value = context.environments.first[@variable] ||= 0
-      context.environments.first[@variable] = value + 1
+      counter_environment = context.environments.first
+      value = counter_environment[@variable_name] || 0
+      counter_environment[@variable_name] = value + 1
 
       output << value.to_s
       output

lib/liquid/tags/inline_comment.rb

@@ -1,20 +1,11 @@
 # 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 self.migrate(_tag_name, markup, _tokenizer, _parse_context)
+      markup
+    end
+
     def initialize(tag_name, markup, options)
       super
 

lib/liquid/tags/raw.rb

@@ -16,6 +16,31 @@ module Liquid
     Syntax = /\A\s*\z/
     FullTokenPossiblyInvalid = /\A(.*)#{TagStart}\s*(\w+)\s*(.*)?#{TagEnd}\z/om
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      raise SyntaxError unless Syntax.match?(markup)
+
+      new_body = migrate_body(tag_name, tokenizer, parse_context)
+      [markup, new_body]
+    end
+
+    def self.migrate_body(start_tag_name, tokenizer, parse_context)
+      block_delimiter = "end#{start_tag_name}"
+
+      body = +''
+      while (token = tokenizer.shift)
+        match = token.match(FullTokenPossiblyInvalid)
+        if match && block_delimiter == match[2]
+          body << Utils.match_captures_replace(match, { 3 => "" })
+          return body
+        end
+        body << token unless token.empty?
+      end
+
+      raise SyntaxError
+    end
+
+    attr_reader :body
+
     def initialize(tag_name, markup, parse_context)
       super
 

lib/liquid/tags/render.rb

@@ -8,19 +8,19 @@ module Liquid
   # @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)
+  #   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#render-passing-variables-to-a-snippet)
   #   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).
+  #   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)
+  #   > 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' %}
@@ -29,9 +29,25 @@ module Liquid
     FOR = 'for'
     SYNTAX = /(#{QuotedString}+)(\s+(with|#{FOR})\s+(#{QuotedFragment}+))?(\s+(?:as)\s+(#{VariableSegment}+))?/o
 
+    def self.migrate(_tag_name, markup, _tokenizer, parse_context)
+      match = markup.match(SYNTAX)
+
+      template_name = Expression.lax_migrate(match[1])
+      variable_name = Expression.lax_migrate(match[4]) if match[4]
+
+      new_markup = Utils.match_captures_replace(match, { 1 => template_name, 4 => variable_name }.compact)
+      new_markup << Utils.migrate_tag_attributes(markup)
+
+      # replace scanned over characters with a space to ensure there is a space
+      # to separate the tag name and the variable name
+      new_markup.prepend(" ") if match.begin(0) > 0
+
+      new_markup
+    end
+
     disable_tags "include"
 
-    attr_reader :template_name_expr, :attributes
+    attr_reader :template_name_expr, :variable_name_expr, :attributes, :alias_name
 
     def initialize(tag_name, markup, options)
       super
@@ -45,7 +61,7 @@ module Liquid
       @alias_name = Regexp.last_match(6)
       @variable_name_expr = variable_name ? parse_expression(variable_name) : nil
       @template_name_expr = parse_expression(template_name)
-      @for = (with_or_for == FOR)
+      @is_for_loop = (with_or_for == FOR)
 
       @attributes = {}
       markup.scan(TagAttributes) do |key, value|
@@ -53,6 +69,10 @@ module Liquid
       end
     end
 
+    def for_loop?
+      @is_for_loop
+    end
+
     def render_to_output_buffer(context, output)
       render_tag(context, output)
     end
@@ -85,7 +105,7 @@ module Liquid
       }
 
       variable = @variable_name_expr ? context.evaluate(@variable_name_expr) : nil
-      if @for && variable.respond_to?(:each) && variable.respond_to?(:count)
+      if @is_for_loop && variable.respond_to?(:each) && variable.respond_to?(:count)
         forloop = Liquid::ForloopDrop.new(template_name, variable.count, nil)
         variable.each { |var| render_partial_func.call(var, forloop) }
       else
@@ -99,6 +119,7 @@ module Liquid
       def children
         [
           @node.template_name_expr,
+          @node.variable_name_expr,
         ] + @node.attributes.values
       end
     end

lib/liquid/tags/table_row.rb

@@ -11,7 +11,7 @@ module Liquid
   #   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.
+  #   > Every `tablerow` loop has an associated [`tablerowloop` object](/api/liquid/objects/tablerowloop) with information about the loop.
   # @liquid_syntax
   #   {% tablerow variable in array %}
   #     expression
@@ -26,6 +26,20 @@ module Liquid
   class TableRow < Block
     Syntax = /(\w+)\s+in\s+(#{QuotedFragment}+)/o
 
+    def self.migrate(tag_name, markup, tokenizer, parse_context)
+      match = markup.match(Syntax) || raise(SyntaxError)
+
+      new_collection_name = Expression.lax_migrate(match[2])
+
+      new_markup = Utils.match_captures_replace(match, { 2 => new_collection_name }.compact)
+      new_markup << Utils.migrate_tag_attributes(markup)
+
+      new_body, unknown_tag = migrate_body(tag_name, tokenizer, parse_context)
+      raise SyntaxError if unknown_tag
+
+      [new_markup, new_body]
+    end
+
     attr_reader :variable_name, :collection_name, :attributes
 
     def initialize(tag_name, markup, options)
@@ -51,7 +65,7 @@ module Liquid
       collection = Utils.slice_collection(collection, from, to)
       length     = collection.length
 
-      cols = context.evaluate(@attributes['cols']).to_i
+      cols = @attributes.key?('cols') ? context.evaluate(@attributes['cols']).to_i : length
 
       output << "<tr class=\"row1\">\n"
       context.stack do

lib/liquid/tags/unless.rb

@@ -11,11 +11,11 @@ module Liquid
   #   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.
+  #   > 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
-  #   {% endif %}
+  #   {% 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

lib/liquid/template.rb

@@ -96,6 +96,11 @@ module Liquid
       def parse(source, options = {})
         new.parse(source, options)
       end
+
+      def migrate(source, parse_options = {})
+        parse(source, parse_options) # raise if source has syntax errors
+        new.migrate(source, parse_options)
+      end
     end
 
     def initialize
@@ -112,6 +117,12 @@ module Liquid
       self
     end
 
+    def migrate(source, parse_options = {})
+      parse_context = configure_options(parse_options.merge(disable_liquid_c_nodes: true))
+      tokenizer     = parse_context.new_tokenizer(source, start_line_number: @line_numbers && 1)
+      Document.migrate(tokenizer, parse_context)
+    end
+
     def registers
       @registers ||= {}
     end

lib/liquid/tokenizer.rb

@@ -8,11 +8,15 @@ module Liquid
       @source         = source.to_s.to_str
       @line_number    = line_number || (line_numbers ? 1 : nil)
       @for_liquid_tag = for_liquid_tag
+      @offset         = 0
       @tokens         = tokenize
     end
 
     def shift
-      (token = @tokens.shift) || return
+      token = @tokens[@offset]
+      return nil unless token
+
+      @offset += 1
 
       if @line_number
         @line_number += @for_liquid_tag ? 1 : token.count("\n")
@@ -21,6 +25,10 @@ module Liquid
       token
     end
 
+    def more?
+      @offset < @tokens.length
+    end
+
     private
 
     def tokenize
@@ -31,7 +39,9 @@ module Liquid
       tokens = @source.split(TemplateParser)
 
       # removes the rogue empty element at the beginning of the array
-      tokens.shift if tokens[0]&.empty?
+      if tokens[0]&.empty?
+        @offset += 1
+      end
 
       tokens
     end

lib/liquid/utils.rb

@@ -89,5 +89,48 @@ module Liquid
       # Otherwise return the object itself
       obj
     end
+
+    def self.migrate_stripped(markup)
+      match = markup.match(/\A\s*(.*?)\s*\z/m)
+      new_markup = yield match[1]
+      Utils.match_captures_replace(match, 1 => new_markup)
+    end
+
+    def self.migrate_tag_attributes(markup)
+      attributes = []
+      markup.scan(/\s*,?\s*#{TagAttributes}/) do
+        tag_match = Regexp.last_match
+        new_value_markup = Expression.lax_migrate(tag_match[2])
+        attribute_markup = Utils.match_captures_replace(tag_match, { 2 => new_value_markup })
+        unless attribute_markup.match?(/\A[,\s]/)
+          attribute_markup.prepend(", ")
+        end
+        attributes << attribute_markup
+      end
+      return "" if attributes.empty?
+      attributes.join
+    end
+
+    # @api private
+    def self.match_capture_replace(match, capture_number, replacement_string)
+      match_captures_replace(match, { capture_number => replacement_string })
+    end
+
+    def self.match_captures_replace(match, replacements = {})
+      new_string = match[0].dup
+      capture_numbers = replacements.keys
+      unless capture_numbers.all?(Integer)
+        raise TypeError, "Currently, only numbered captures are supported"
+      end
+      # replace from later captures first, to avoid affecting the position for following replacements
+      match_begin = match.begin(0)
+      capture_numbers.sort.reverse_each do |capture_number|
+        replacement_string = replacements.fetch(capture_number)
+        capture_start = match.begin(capture_number)
+        capture_length = match.end(capture_number) - capture_start
+        new_string[capture_start - match_begin, capture_length] = replacement_string
+      end
+      new_string
+    end
   end
 end

lib/liquid/variable.rb

@@ -41,6 +41,79 @@ module Liquid
       "in \"{{#{markup}}}\""
     end
 
+    STRICT_PARSE_CONTEXT = ParseContext.new(error_mode: :strict)
+    private_constant :STRICT_PARSE_CONTEXT
+
+    def self.migrate(markup, parse_context)
+      new(markup, STRICT_PARSE_CONTEXT)
+      # TODO: migrate non-integer range expression literals
+      markup
+    rescue Liquid::SyntaxError
+      raise if parse_context.error_mode == :strict
+      lax_migrate(markup, parse_context)
+    end
+
+    def self.lax_migrate(markup, parse_context)
+      # unanchored match that may skip over characters preceding the name expression
+      markup_match = markup.match(MarkupWithQuotedFragment)
+      unless markup_match
+        # Treated as a blank variable (e.g. `{{ -}}`), which outputs nothing
+        # but may still have an effect on whitespace trimming
+        return ""
+      end
+
+      name_markup = markup_match[1]
+      filters_markup = markup_match[2]
+
+      new_name_markup = Expression.lax_migrate(name_markup)
+
+      new_filter_markup = ""
+      # unanchored match that may skip over characters preceding the pipe for the first filter
+      if (filters_match = filters_markup.match(/\s*#{FilterMarkupRegex}/o))
+        filters = filters_match[1].scan(FilterParser) # may skip over unterminated quote characters
+        filters.map! do |f|
+          filter_match = f.match(/\A(\s*)\W*(\w+)(\s*)/)
+          next unless filter_match
+
+          # omit non-word characters preceding the filter name that the lax parser skips over
+          transformed_filter = +"#{filter_match[1]}#{filter_match[2]}#{filter_match[3]}"
+
+          filter_args = []
+          f.scan(/#{FilterArgsRegex}\s*/o) do # may skip over characters before the argument separator
+            filter_arg_match = Regexp.last_match
+            new_filter_arg = lax_migrate_filter_argument(filter_arg_match[1])
+            filter_arg_string = Utils.match_captures_replace(filter_arg_match, 1 => new_filter_arg)
+            filter_arg_string = filter_arg_string[1...] # remove separator character
+            filter_args << filter_arg_string
+          end
+
+          unless filter_args.empty?
+            transformed_filter << ":" << filter_args.join(",")
+          end
+
+          transformed_filter
+        end
+        filters.compact!
+        new_filters_markup = filters.join('|')
+
+        # include pipe separator along with whitespace surrounding it
+        new_filter_markup = Utils.match_captures_replace(filters_match, 1 => new_filters_markup)
+      end
+
+      new_markup = Utils.match_captures_replace(markup_match, 1 => new_name_markup, 2 => new_filter_markup)
+      new_markup.prepend(" ") if markup_match.begin(0) > 0
+      new_markup
+    end
+
+    def self.lax_migrate_filter_argument(unparsed_arg)
+      if (match = unparsed_arg.match(JustTagAttributes))
+        new_value_markup = Expression.lax_migrate(match[2])
+        Utils.match_captures_replace(match, 2 => new_value_markup)
+      else
+        Expression.lax_migrate(unparsed_arg)
+      end
+    end
+
     def lax_parse(markup)
       @filters = []
       return unless markup =~ MarkupWithQuotedFragment

lib/liquid/variable_lookup.rb

@@ -10,6 +10,43 @@ module Liquid
       new(markup)
     end
 
+    LITERALS = Expression::LITERALS.keys.freeze
+    private_constant :LITERALS
+
+    def self.lax_migrate(markup)
+      new_markup = nil
+      last_match = nil
+      first_match = nil
+      markup.scan(VariableParser) do |lookup|
+        last_match = Regexp.last_match
+        first_match ||= last_match
+        new_markup ||= +""
+        if lookup&.start_with?('[') && lookup&.end_with?(']')
+          new_markup << "[" << Expression.lax_migrate(lookup[1..-2]) << "]"
+        elsif !lookup.match?(/\A#{Liquid::Lexer::IDENTIFIER}\z/)
+          # quote non-strictly valid identifiers
+          new_markup << "['" << lookup << "']"
+        else
+          new_markup << "." unless new_markup.empty?
+          new_markup << lookup
+        end
+      end
+
+      case new_markup
+      when nil
+        # `markup.scan(VariableParser)` may skip over all characters
+        new_markup ||= " nil "
+      when Expression::INTEGERS_REGEX, Expression::RANGES_REGEX, Expression::FLOATS_REGEX, *LITERALS
+        # Quote variable lookups that match literals after characters are skipped by regex scanning
+        new_markup = "['#{new_markup}']"
+      else
+        new_markup.prepend(" ") if first_match.begin(0) > 0
+        new_markup << ' ' if last_match.end(0) < markup.length
+      end
+
+      new_markup
+    end
+
     def initialize(markup)
       lookups = markup.scan(VariableParser)
 
@@ -32,6 +69,10 @@ module Liquid
       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)
@@ -55,7 +96,7 @@ 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 = "5.4.0.alpha"
+  VERSION = "5.4.0"
 end

test/integration/assign_test.rb

@@ -6,51 +6,42 @@ class AssignTest < Minitest::Test
   include Liquid
 
   def test_assign_with_hyphen_in_variable_name
-    template_source = <<-END_TEMPLATE
-    {% assign this-thing = 'Print this-thing' %}
-    {{ this-thing }}
+    template_source = <<~END_TEMPLATE
+      {% assign this-thing = 'Print this-thing' -%}
+      {{ this-thing -}}
     END_TEMPLATE
-    template        = Template.parse(template_source)
-    rendered        = template.render!
-    assert_equal("Print this-thing", rendered.strip)
+    assert_template_result("Print this-thing", template_source)
   end
 
   def test_assigned_variable
     assert_template_result('.foo.',
       '{% assign foo = values %}.{{ foo[0] }}.',
-      'values' => %w(foo bar baz))
+      { 'values' => %w(foo bar baz) })
 
     assert_template_result('.bar.',
       '{% assign foo = values %}.{{ foo[1] }}.',
-      'values' => %w(foo bar baz))
+      { 'values' => %w(foo bar baz) })
   end
 
   def test_assign_with_filter
     assert_template_result('.bar.',
       '{% assign foo = values | split: "," %}.{{ foo[1] }}.',
-      'values' => "foo,bar,baz")
+      { 'values' => "foo,bar,baz" })
   end
 
   def test_assign_syntax_error
-    assert_match_syntax_error(/assign/,
-      '{% assign foo not values %}.',
-      'values' => "foo,bar,baz")
+    assert_match_syntax_error(/assign/, '{% assign foo not values %}.')
   end
 
   def test_assign_uses_error_mode
-    with_error_mode(:strict) do
-      assert_raises(SyntaxError) do
-        Template.parse("{% assign foo = ('X' | downcase) %}")
-      end
-    end
-    with_error_mode(:lax) do
-      assert(Template.parse("{% assign foo = ('X' | downcase) %}"))
-    end
+    assert_match_syntax_error("Expected dotdot but found pipe in ",
+      "{% assign foo = ('X' | downcase) %}", error_mode: :strict)
+    assert_template_result("", "{% assign foo = ('X' | downcase) %}", error_mode: :lax)
   end
 
   def test_expression_with_whitespace_in_square_brackets
     source = "{% assign r = a[ 'b' ] %}{{ r }}"
-    assert_template_result('result', source, 'a' => { 'b' => 'result' })
+    assert_template_result('result', source, { 'a' => { 'b' => 'result' } })
   end
 
   def test_assign_score_exceeding_resource_limit

test/integration/blank_test.rb

@@ -9,12 +9,6 @@ class FoobarTag < Liquid::Tag
   end
 end
 
-class BlankTestFileSystem
-  def read_template_file(template_path)
-    template_path
-  end
-end
-
 class BlankTest < Minitest::Test
   include Liquid
   N = 10
@@ -33,7 +27,7 @@ class BlankTest < Minitest::Test
 
   def test_new_tags_are_not_blank_by_default
     with_custom_tag('foobar', FoobarTag) do
-      assert_template_result(" " * N, wrap_in_for("{% foobar %}"))
+      assert_equal(" " * N, Liquid::Template.parse(wrap_in_for("{% foobar %}")).render!)
     end
   end
 
@@ -95,10 +89,12 @@ class BlankTest < Minitest::Test
   end
 
   def test_include_is_blank
-    Liquid::Template.file_system = BlankTestFileSystem.new
-    assert_template_result("foobar" * (N + 1), wrap("{% include 'foobar' %}"))
-    assert_template_result(" foobar " * (N + 1), wrap("{% include ' foobar ' %}"))
-    assert_template_result("   " * (N + 1), wrap(" {% include ' ' %} "))
+    assert_template_result("foobar" * (N + 1), wrap("{% include 'foobar' %}"),
+      partials: { 'foobar' => 'foobar' })
+    assert_template_result(" foobar " * (N + 1), wrap("{% include ' foobar ' %}"),
+      partials: { ' foobar ' => ' foobar ' })
+    assert_template_result("   " * (N + 1), wrap(" {% include ' ' %} "),
+      partials: { ' ' => ' ' })
   end
 
   def test_case_is_blank

test/integration/block_test.rb

@@ -6,10 +6,8 @@ class BlockTest < Minitest::Test
   include Liquid
 
   def test_unexpected_end_tag
-    exc = assert_raises(SyntaxError) do
-      Template.parse("{% if true %}{% endunless %}")
-    end
-    assert_equal(exc.message, "Liquid syntax error: 'endunless' is not a valid delimiter for if tags. use endif")
+    source = '{% if true %}{% endunless %}'
+    assert_match_syntax_error("Liquid syntax error (line 1): 'endunless' is not a valid delimiter for if tags. use endif", source)
   end
 
   def test_with_custom_tag

test/integration/capture_test.rb

@@ -10,44 +10,38 @@ class CaptureTest < Minitest::Test
   end
 
   def test_capture_with_hyphen_in_variable_name
-    template_source = <<-END_TEMPLATE
-    {% capture this-thing %}Print this-thing{% endcapture %}
-    {{ this-thing }}
+    template_source = <<~END_TEMPLATE
+      {% capture this-thing %}Print this-thing{% endcapture -%}
+      {{ this-thing -}}
     END_TEMPLATE
-    template        = Template.parse(template_source)
-    rendered        = template.render!
-    assert_equal("Print this-thing", rendered.strip)
+    assert_template_result("Print this-thing", template_source)
   end
 
   def test_capture_to_variable_from_outer_scope_if_existing
-    template_source = <<-END_TEMPLATE
-    {% assign var = '' %}
-    {% if true %}
-    {% capture var %}first-block-string{% endcapture %}
-    {% endif %}
-    {% if true %}
-    {% capture var %}test-string{% endcapture %}
-    {% endif %}
-    {{var}}
+    template_source = <<~END_TEMPLATE
+      {% assign var = '' -%}
+      {% if true -%}
+        {% capture var %}first-block-string{% endcapture -%}
+      {% endif -%}
+      {% if true -%}
+        {% capture var %}test-string{% endcapture -%}
+      {% endif -%}
+      {{var-}}
     END_TEMPLATE
-    template        = Template.parse(template_source)
-    rendered        = template.render!
-    assert_equal("test-string", rendered.gsub(/\s/, ''))
+    assert_template_result("test-string", template_source)
   end
 
   def test_assigning_from_capture
-    template_source = <<-END_TEMPLATE
-    {% assign first = '' %}
-    {% assign second = '' %}
-    {% for number in (1..3) %}
-    {% capture first %}{{number}}{% endcapture %}
-    {% assign second = first %}
-    {% endfor %}
-    {{ first }}-{{ second }}
+    template_source = <<~END_TEMPLATE
+      {% assign first = '' -%}
+      {% assign second = '' -%}
+      {% for number in (1..3) -%}
+        {% capture first %}{{number}}{% endcapture -%}
+        {% assign second = first -%}
+      {% endfor -%}
+      {{ first }}-{{ second -}}
     END_TEMPLATE
-    template        = Template.parse(template_source)
-    rendered        = template.render!
-    assert_equal("3-3", rendered.gsub(/\s/, ''))
+    assert_template_result("3-3", template_source)
   end
 
   def test_increment_assign_score_by_bytes_not_characters

test/integration/context_test.rb

@@ -102,7 +102,7 @@ class ContextTest < Minitest::Test
   end
 
   def test_variables_not_existing
-    assert_nil(@context['does_not_exist'])
+    assert_template_result("true", "{% if does_not_exist == nil %}true{% endif %}")
   end
 
   def test_scoping
@@ -121,22 +121,18 @@ class ContextTest < Minitest::Test
   end
 
   def test_length_query
-    @context['numbers'] = [1, 2, 3, 4]
+    assert_template_result("true", "{% if numbers.size == 4 %}true{% endif %}",
+      { "numbers" => [1, 2, 3, 4] })
 
-    assert_equal(4, @context['numbers.size'])
+    assert_template_result("true", "{% if numbers.size == 4 %}true{% endif %}",
+      { "numbers" => { 1 => 1, 2 => 2, 3 => 3, 4 => 4 } })
 
-    @context['numbers'] = { 1 => 1, 2 => 2, 3 => 3, 4 => 4 }
-
-    assert_equal(4, @context['numbers.size'])
-
-    @context['numbers'] = { 1 => 1, 2 => 2, 3 => 3, 4 => 4, 'size' => 1000 }
-
-    assert_equal(1000, @context['numbers.size'])
+    assert_template_result("true", "{% if numbers.size == 1000 %}true{% endif %}",
+      { "numbers" => { 1 => 1, 2 => 2, 3 => 3, 4 => 4, 'size' => 1000 } })
   end
 
   def test_hyphenated_variable
-    @context['oh-my'] = 'godz'
-    assert_equal('godz', @context['oh-my'])
+    assert_template_result("godz", "{{ oh-my }}", { "oh-my" => 'godz' })
   end
 
   def test_add_filter
@@ -188,24 +184,24 @@ class ContextTest < Minitest::Test
   end
 
   def test_hierachical_data
-    @context['hash'] = { "name" => 'tobi' }
-    assert_equal('tobi', @context['hash.name'])
-    assert_equal('tobi', @context['hash["name"]'])
+    assigns = { 'hash' => { "name" => 'tobi' } }
+    assert_template_result("tobi", "{{ hash.name }}", assigns)
+    assert_template_result("tobi", '{{ hash["name"] }}', assigns)
   end
 
   def test_keywords
-    assert_equal(true, @context['true'])
-    assert_equal(false, @context['false'])
+    assert_template_result("pass", "{% if true == expect %}pass{% endif %}", { "expect" => true })
+    assert_template_result("pass", "{% if false == expect %}pass{% endif %}", { "expect" => false })
   end
 
   def test_digits
-    assert_equal(100, @context['100'])
-    assert_equal(100.00, @context['100.00'])
+    assert_template_result("pass", "{% if 100 == expect %}pass{% endif %}", { "expect" => 100 })
+    assert_template_result("pass", "{% if 100.00 == expect %}pass{% endif %}", { "expect" => 100.00 })
   end
 
   def test_strings
-    assert_equal("hello!", @context['"hello!"'])
-    assert_equal("hello!", @context["'hello!'"])
+    assert_template_result("hello!", '{{ "hello!" }}')
+    assert_template_result("hello!", "{{ 'hello!' }}")
   end
 
   def test_merge
@@ -217,99 +213,90 @@ class ContextTest < Minitest::Test
   end
 
   def test_array_notation
-    @context['test'] = [1, 2, 3, 4, 5]
-
-    assert_equal(1, @context['test[0]'])
-    assert_equal(2, @context['test[1]'])
-    assert_equal(3, @context['test[2]'])
-    assert_equal(4, @context['test[3]'])
-    assert_equal(5, @context['test[4]'])
+    assigns = { "test" => ["a", "b"] }
+    assert_template_result("a", "{{ test[0] }}", assigns)
+    assert_template_result("b", "{{ test[1] }}", assigns)
+    assert_template_result("pass", "{% if test[2] == nil %}pass{% endif %}", assigns)
   end
 
   def test_recoursive_array_notation
-    @context['test'] = { 'test' => [1, 2, 3, 4, 5] }
+    assigns = { "test" => { 'test' => [1, 2, 3, 4, 5] } }
+    assert_template_result("1", "{{ test.test[0] }}", assigns)
 
-    assert_equal(1, @context['test.test[0]'])
-
-    @context['test'] = [{ 'test' => 'worked' }]
-
-    assert_equal('worked', @context['test[0].test'])
+    assigns = { "test" => [{ 'test' => 'worked' }] }
+    assert_template_result("worked", "{{ test[0].test }}", assigns)
   end
 
   def test_hash_to_array_transition
-    @context['colors'] = {
+    assigns = { 'colors' => {
       'Blue' => ['003366', '336699', '6699CC', '99CCFF'],
       'Green' => ['003300', '336633', '669966', '99CC99'],
       'Yellow' => ['CC9900', 'FFCC00', 'FFFF99', 'FFFFCC'],
       'Red' => ['660000', '993333', 'CC6666', 'FF9999'],
-    }
+    } }
 
-    assert_equal('003366', @context['colors.Blue[0]'])
-    assert_equal('FF9999', @context['colors.Red[3]'])
+    assert_template_result("003366", "{{ colors.Blue[0] }}", assigns)
+    assert_template_result("FF9999", "{{ colors.Red[3] }}", assigns)
   end
 
   def test_try_first
-    @context['test'] = [1, 2, 3, 4, 5]
+    assigns = { 'test' => [1, 2, 3, 4, 5] }
+    assert_template_result("1", "{{ test.first }}", assigns)
+    assert_template_result("pass", "{% if test.last == 5 %}pass{% endif %}", assigns)
 
-    assert_equal(1, @context['test.first'])
-    assert_equal(5, @context['test.last'])
+    assigns = { "test" => { "test" => [1, 2, 3, 4, 5] } }
+    assert_template_result("1", "{{ test.test.first }}", assigns)
+    assert_template_result("5", "{{ test.test.last }}", assigns)
 
-    @context['test'] = { 'test' => [1, 2, 3, 4, 5] }
-
-    assert_equal(1, @context['test.test.first'])
-    assert_equal(5, @context['test.test.last'])
-
-    @context['test'] = [1]
-    assert_equal(1, @context['test.first'])
-    assert_equal(1, @context['test.last'])
+    assigns = { "test" => [1] }
+    assert_template_result("1", "{{ test.first }}", assigns)
+    assert_template_result("1", "{{ test.last }}", assigns)
   end
 
   def test_access_hashes_with_hash_notation
-    @context['products'] = { 'count' => 5, 'tags' => ['deepsnow', 'freestyle'] }
-    @context['product']  = { 'variants' => [{ 'title' => 'draft151cm' }, { 'title' => 'element151cm' }] }
+    assigns = { 'products' => { 'count' => 5, 'tags' => ['deepsnow', 'freestyle'] } }
+    assert_template_result("5", '{{ products["count"] }}', assigns)
+    assert_template_result("deepsnow", '{{ products["tags"][0] }}', assigns)
+    assert_template_result("deepsnow", '{{ products["tags"].first }}', assigns)
 
-    assert_equal(5, @context['products["count"]'])
-    assert_equal('deepsnow', @context['products["tags"][0]'])
-    assert_equal('deepsnow', @context['products["tags"].first'])
-    assert_equal('draft151cm', @context['product["variants"][0]["title"]'])
-    assert_equal('element151cm', @context['product["variants"][1]["title"]'])
-    assert_equal('draft151cm', @context['product["variants"][0]["title"]'])
-    assert_equal('element151cm', @context['product["variants"].last["title"]'])
+    assigns = { 'product' => { 'variants' => [{ 'title' => 'draft151cm' }, { 'title' => 'element151cm' }] } }
+    assert_template_result("draft151cm", '{{ product["variants"][0]["title"] }}', assigns)
+    assert_template_result("element151cm", '{{ product["variants"][1]["title"] }}', assigns)
+    assert_template_result("draft151cm", '{{ product["variants"][0]["title"] }}', assigns)
+    assert_template_result("element151cm", '{{ product["variants"].last["title"] }}', assigns)
   end
 
   def test_access_variable_with_hash_notation
-    @context['foo'] = 'baz'
-    @context['bar'] = 'foo'
-
-    assert_equal('baz', @context['["foo"]'])
-    assert_equal('baz', @context['[bar]'])
+    assert_template_result('baz', '{{ ["foo"] }}', { "foo" => "baz" })
+    assert_template_result('baz', '{{ [bar] }}', { 'foo' => 'baz', 'bar' => 'foo' })
   end
 
   def test_access_hashes_with_hash_access_variables
-    @context['var']      = 'tags'
-    @context['nested']   = { 'var' => 'tags' }
-    @context['products'] = { 'count' => 5, 'tags' => ['deepsnow', 'freestyle'] }
+    assigns = {
+      'var' => 'tags',
+      'nested' => { 'var' => 'tags' },
+      'products' => { 'count' => 5, 'tags' => ['deepsnow', 'freestyle'] },
+    }
 
-    assert_equal('deepsnow', @context['products[var].first'])
-    assert_equal('freestyle', @context['products[nested.var].last'])
+    assert_template_result('deepsnow', '{{ products[var].first }}', assigns)
+    assert_template_result('freestyle', '{{ products[nested.var].last }}', assigns)
   end
 
   def test_hash_notation_only_for_hash_access
-    @context['array'] = [1, 2, 3, 4, 5]
-    @context['hash']  = { 'first' => 'Hello' }
+    assigns = { "array" => [1, 2, 3, 4, 5] }
+    assert_template_result("1", "{{ array.first }}", assigns)
+    assert_template_result("pass", '{% if array["first"] == nil %}pass{% endif %}', assigns)
 
-    assert_equal(1, @context['array.first'])
-    assert_nil(@context['array["first"]'])
-    assert_equal('Hello', @context['hash["first"]'])
+    assert_template_result("Hello", '{{ hash["first"] }}', { "hash" => { "first" => "Hello" } })
   end
 
   def test_first_can_appear_in_middle_of_callchain
-    @context['product'] = { 'variants' => [{ 'title' => 'draft151cm' }, { 'title' => 'element151cm' }] }
+    assigns = { "product" => { 'variants' => [{ 'title' => 'draft151cm' }, { 'title' => 'element151cm' }] } }
 
-    assert_equal('draft151cm', @context['product.variants[0].title'])
-    assert_equal('element151cm', @context['product.variants[1].title'])
-    assert_equal('draft151cm', @context['product.variants.first.title'])
-    assert_equal('element151cm', @context['product.variants.last.title'])
+    assert_template_result('draft151cm', '{{ product.variants[0].title }}', assigns)
+    assert_template_result('element151cm', '{{ product.variants[1].title }}', assigns)
+    assert_template_result('draft151cm', '{{ product.variants.first.title }}', assigns)
+    assert_template_result('element151cm', '{{ product.variants.last.title }}', assigns)
   end
 
   def test_cents
@@ -351,10 +338,12 @@ class ContextTest < Minitest::Test
   end
 
   def test_ranges
-    @context.merge("test" => '5')
-    assert_equal((1..5), @context['(1..5)'])
-    assert_equal((1..5), @context['(1..test)'])
-    assert_equal((5..5), @context['(test..test)'])
+    assert_template_result("1..5", '{{ (1..5) }}')
+    assert_template_result("pass", '{% if (1..5) == expect %}pass{% endif %}', { "expect" => (1..5) })
+
+    assigns = { "test" => '5' }
+    assert_template_result("1..5", "{{ (1..test) }}", assigns)
+    assert_template_result("5..5", "{{ (test..test) }}", assigns)
   end
 
   def test_cents_through_drop_nestedly

test/integration/document_test.rb

@@ -6,16 +6,12 @@ class DocumentTest < Minitest::Test
   include Liquid
 
   def test_unexpected_outer_tag
-    exc = assert_raises(SyntaxError) do
-      Template.parse("{% else %}")
-    end
-    assert_equal(exc.message, "Liquid syntax error: Unexpected outer 'else' tag")
+    source = "{% else %}"
+    assert_match_syntax_error("Liquid syntax error (line 1): Unexpected outer 'else' tag", source)
   end
 
   def test_unknown_tag
-    exc = assert_raises(SyntaxError) do
-      Template.parse("{% foo %}")
-    end
-    assert_equal(exc.message, "Liquid syntax error: Unknown tag 'foo'")
+    source = "{% foo %}"
+    assert_match_syntax_error("Liquid syntax error (line 1): Unknown tag 'foo'", source)
   end
 end

test/integration/error_handling_test.rb

@@ -63,9 +63,7 @@ class ErrorHandlingTest < Minitest::Test
   end
 
   def test_missing_endtag_parse_time_error
-    assert_raises(Liquid::SyntaxError) do
-      Liquid::Template.parse(' {% for a in b %} ... ')
-    end
+    assert_match_syntax_error(/: 'for' tag was never closed\z/, ' {% for a in b %} ... ')
   end
 
   def test_unrecognized_operator
@@ -84,33 +82,26 @@ class ErrorHandlingTest < Minitest::Test
   end
 
   def test_with_line_numbers_adds_numbers_to_parser_errors
-    err = assert_raises(SyntaxError) do
-      Liquid::Template.parse('
-          foobar
+    source = <<~LIQUID
+      foobar
 
-          {% "cat" | foobar %}
+      {% "cat" | foobar %}
 
-          bla
-        ',
-        line_numbers: true)
-    end
-
-    assert_match(/Liquid syntax error \(line 4\)/, err.message)
+      bla
+    LIQUID
+    assert_match_syntax_error(/Liquid syntax error \(line 3\)/, source)
   end
 
   def test_with_line_numbers_adds_numbers_to_parser_errors_with_whitespace_trim
-    err = assert_raises(SyntaxError) do
-      Liquid::Template.parse('
-          foobar
+    source = <<~LIQUID
+      foobar
 
-          {%- "cat" | foobar -%}
+      {%- "cat" | foobar -%}
 
-          bla
-        ',
-        line_numbers: true)
-    end
+      bla
+    LIQUID
 
-    assert_match(/Liquid syntax error \(line 4\)/, err.message)
+    assert_match_syntax_error(/Liquid syntax error \(line 3\)/, source)
   end
 
   def test_parsing_warn_with_line_numbers_adds_numbers_to_lexer_errors
@@ -145,20 +136,17 @@ class ErrorHandlingTest < Minitest::Test
   end
 
   def test_syntax_errors_in_nested_blocks_have_correct_line_number
-    err = assert_raises(SyntaxError) do
-      Liquid::Template.parse('
-          foobar
+    source = <<~LIQUID
+      foobar
 
-          {% if 1 != 2 %}
-            {% foo %}
-          {% endif %}
+      {% if 1 != 2 %}
+        {% foo %}
+      {% endif %}
 
-          bla
-                ',
-        line_numbers: true)
-    end
+      bla
+    LIQUID
 
-    assert_equal("Liquid syntax error (line 5): Unknown tag 'foo'", err.message)
+    assert_match_syntax_error("Liquid syntax error (line 4): Unknown tag 'foo'", source)
   end
 
   def test_strict_error_messages

test/integration/expression_test.rb

@@ -4,43 +4,46 @@ require 'test_helper'
 
 class ExpressionTest < Minitest::Test
   def test_keyword_literals
-    assert_equal(true, parse_and_eval("true"))
-    assert_equal(true, parse_and_eval(" true "))
+    assert_template_result("true", "{{ true }}")
+    assert_expression_result(true, "true")
   end
 
   def test_string
-    assert_equal("single quoted", parse_and_eval("'single quoted'"))
-    assert_equal("double quoted", parse_and_eval('"double quoted"'))
-    assert_equal("spaced", parse_and_eval(" 'spaced' "))
-    assert_equal("spaced2", parse_and_eval(' "spaced2" '))
+    assert_template_result("single quoted", "{{'single quoted'}}")
+    assert_template_result("double quoted", '{{"double quoted"}}')
+    assert_template_result("spaced", "{{ 'spaced' }}")
+    assert_template_result("spaced2", "{{ 'spaced2' }}")
   end
 
   def test_int
-    assert_equal(123, parse_and_eval("123"))
-    assert_equal(456, parse_and_eval(" 456 "))
-    assert_equal(12, parse_and_eval("012"))
+    assert_template_result("456", "{{ 456 }}")
+    assert_expression_result(123, "123")
+    assert_expression_result(12, "012")
   end
 
   def test_float
-    assert_equal(1.5, parse_and_eval("1.5"))
-    assert_equal(2.5, parse_and_eval(" 2.5 "))
+    assert_template_result("2.5", "{{ 2.5 }}")
+    assert_expression_result(1.5, "1.5")
   end
 
   def test_range
-    assert_equal(1..2, parse_and_eval("(1..2)"))
-    assert_equal(3..4, parse_and_eval(" ( 3 .. 4 ) "))
+    assert_template_result("3..4", "{{ ( 3 .. 4 ) }}")
+    assert_expression_result(1..2, "(1..2)")
+
+    assert_match_syntax_error(
+      "Liquid syntax error (line 1): Invalid expression type 'false' in range expression",
+      "{{ (false..true) }}"
+    )
+    assert_match_syntax_error(
+      "Liquid syntax error (line 1): Invalid expression type '(1..2)' in range expression",
+      "{{ ((1..2)..3) }}"
+    )
   end
 
   private
 
-  def parse_and_eval(markup, **assigns)
-    if Liquid::Template.error_mode == :strict
-      p = Liquid::Parser.new(markup)
-      markup = p.expression
-      p.consume(:end_of_string)
-    end
-    expression = Liquid::Expression.parse(markup)
-    context = Liquid::Context.new(assigns)
-    context.evaluate(expression)
+  def assert_expression_result(expect, markup, **assigns)
+    liquid = "{% if expect == #{markup} %}pass{% else %}got {{ #{markup} }}{% endif %}"
+    assert_template_result("pass", liquid, { "expect" => expect, **assigns })
   end
 end

test/integration/filter_test.rb

@@ -59,84 +59,66 @@ class FiltersTest < Minitest::Test
   end
 
   def test_size
-    @context['var'] = 'abcd'
-    @context.add_filters(MoneyFilter)
-
-    assert_equal('4', Template.parse("{{var | size}}").render(@context))
+    assert_template_result("4", "{{var | size}}", { "var" => 'abcd' })
   end
 
   def test_join
-    @context['var'] = [1, 2, 3, 4]
-
-    assert_equal("1 2 3 4", Template.parse("{{var | join}}").render(@context))
+    assert_template_result("1 2 3 4", "{{var | join}}", { "var" => [1, 2, 3, 4] })
   end
 
   def test_sort
-    @context['value']   = 3
-    @context['numbers'] = [2, 1, 4, 3]
-    @context['words']   = ['expected', 'as', 'alphabetic']
-    @context['arrays']  = ['flower', 'are']
-    @context['case_sensitive'] = ['sensitive', 'Expected', 'case']
-
-    assert_equal('1 2 3 4', Template.parse("{{numbers | sort | join}}").render(@context))
-    assert_equal('alphabetic as expected', Template.parse("{{words | sort | join}}").render(@context))
-    assert_equal('3', Template.parse("{{value | sort}}").render(@context))
-    assert_equal('are flower', Template.parse("{{arrays | sort | join}}").render(@context))
-    assert_equal('Expected case sensitive', Template.parse("{{case_sensitive | sort | join}}").render(@context))
+    assert_template_result("1 2 3 4", "{{numbers | sort | join}}", { "numbers" => [2, 1, 4, 3] })
+    assert_template_result("alphabetic as expected", "{{words | sort | join}}",
+      { "words" => ['expected', 'as', 'alphabetic'] })
+    assert_template_result("3", "{{value | sort}}", { "value" => 3 })
+    assert_template_result('are flower', "{{arrays | sort | join}}", { 'arrays' => ['flower', 'are'] })
+    assert_template_result("Expected case sensitive", "{{case_sensitive | sort | join}}",
+      { "case_sensitive" => ["sensitive", "Expected", "case"] })
   end
 
   def test_sort_natural
-    @context['words']   = ['case', 'Assert', 'Insensitive']
-    @context['hashes']  = [{ 'a' => 'A' }, { 'a' => 'b' }, { 'a' => 'C' }]
-    @context['objects'] = [TestObject.new('A'), TestObject.new('b'), TestObject.new('C')]
-
     # Test strings
-    assert_equal('Assert case Insensitive', Template.parse("{{words | sort_natural | join}}").render(@context))
+    assert_template_result("Assert case Insensitive", "{{words | sort_natural | join}}",
+      { "words" => ["case", "Assert", "Insensitive"] })
 
     # Test hashes
-    assert_equal('A b C', Template.parse("{{hashes | sort_natural: 'a' | map: 'a' | join}}").render(@context))
+    assert_template_result("A b C", "{{hashes | sort_natural: 'a' | map: 'a' | join}}",
+      { "hashes" => [{ "a" => "A" }, { "a" => "b" }, { "a" => "C" }] })
 
     # Test objects
+    @context['objects'] = [TestObject.new('A'), TestObject.new('b'), TestObject.new('C')]
     assert_equal('A b C', Template.parse("{{objects | sort_natural: 'a' | map: 'a' | join}}").render(@context))
   end
 
   def test_compact
-    @context['words']   = ['a', nil, 'b', nil, 'c']
-    @context['hashes']  = [{ 'a' => 'A' }, { 'a' => nil }, { 'a' => 'C' }]
-    @context['objects'] = [TestObject.new('A'), TestObject.new(nil), TestObject.new('C')]
-
     # Test strings
-    assert_equal('a b c', Template.parse("{{words | compact | join}}").render(@context))
+    assert_template_result("a b c", "{{words | compact | join}}",
+      { "words" => ['a', nil, 'b', nil, 'c'] })
 
     # Test hashes
-    assert_equal('A C', Template.parse("{{hashes | compact: 'a' | map: 'a' | join}}").render(@context))
+    assert_template_result("A C", "{{hashes | compact: 'a' | map: 'a' | join}}",
+      { "hashes" => [{ "a" => "A" }, { "a" => nil }, { "a" => "C" }] })
 
     # Test objects
+    @context['objects'] = [TestObject.new('A'), TestObject.new(nil), TestObject.new('C')]
     assert_equal('A C', Template.parse("{{objects | compact: 'a' | map: 'a' | join}}").render(@context))
   end
 
   def test_strip_html
-    @context['var'] = "<b>bla blub</a>"
-
-    assert_equal("bla blub", Template.parse("{{ var | strip_html }}").render(@context))
+    assert_template_result("bla blub", "{{ var | strip_html }}", { "var" => "<b>bla blub</a>" })
   end
 
   def test_strip_html_ignore_comments_with_html
-    @context['var'] = "<!-- split and some <ul> tag --><b>bla blub</a>"
-
-    assert_equal("bla blub", Template.parse("{{ var | strip_html }}").render(@context))
+    assert_template_result("bla blub", "{{ var | strip_html }}",
+      { "var" => "<!-- split and some <ul> tag --><b>bla blub</a>" })
   end
 
   def test_capitalize
-    @context['var'] = "blub"
-
-    assert_equal("Blub", Template.parse("{{ var | capitalize }}").render(@context))
+    assert_template_result("Blub", "{{ var | capitalize }}", { "var" => "blub" })
   end
 
   def test_nonexistent_filter_is_ignored
-    @context['var'] = 1000
-
-    assert_equal('1000', Template.parse("{{ var | xyzzy }}").render(@context))
+    assert_template_result("1000", "{{ var | xyzzy }}", { "var" => 1000 })
   end
 
   def test_filter_with_keyword_arguments

test/integration/output_test.rb

@@ -33,31 +33,25 @@ class OutputTest < Minitest::Test
 
   def setup
     @assigns = {
-      'best_cars' => 'bmw',
       'car' => { 'bmw' => 'good', 'gm' => 'bad' },
     }
   end
 
   def test_variable
-    text = %( {{best_cars}} )
-
-    expected = %( bmw )
-    assert_equal(expected, Template.parse(text).render!(@assigns))
+    assert_template_result(" bmw ", " {{best_cars}} ", { "best_cars" => "bmw" })
   end
 
   def test_variable_traversing_with_two_brackets
-    text = %({{ site.data.menu[include.menu][include.locale] }})
-    assert_equal("it works!", Template.parse(text).render!(
+    source = "{{ site.data.menu[include.menu][include.locale] }}"
+    assert_template_result("it works!", source, {
       "site" => { "data" => { "menu" => { "foo" => { "bar" => "it works!" } } } },
-      "include" => { "menu" => "foo", "locale" => "bar" }
-    ))
+      "include" => { "menu" => "foo", "locale" => "bar" },
+    })
   end
 
   def test_variable_traversing
-    text = %( {{car.bmw}} {{car.gm}} {{car.bmw}} )
-
-    expected = %( good bad good )
-    assert_equal(expected, Template.parse(text).render!(@assigns))
+    source = " {{car.bmw}} {{car.gm}} {{car.bmw}} "
+    assert_template_result(" good bad good ", source, @assigns)
   end
 
   def test_variable_piping
@@ -110,10 +104,11 @@ class OutputTest < Minitest::Test
   end
 
   def test_multiple_pipings
+    assigns = { 'best_cars' => 'bmw' }
     text     = %( {{ best_cars | cite_funny | paragraph }} )
     expected = %( <p>LOL: bmw</p> )
 
-    assert_equal(expected, Template.parse(text).render!(@assigns, filters: [FunnyFilter]))
+    assert_equal(expected, Template.parse(text).render!(assigns, filters: [FunnyFilter]))
   end
 
   def test_link_to

test/integration/parsing_quirks_test.rb

@@ -129,6 +129,6 @@ class ParsingQuirksTest < Minitest::Test
   end
 
   def test_contains_in_id
-    assert_template_result(' YES ', '{% if containsallshipments == true %} YES {% endif %}', 'containsallshipments' => true)
+    assert_template_result(' YES ', '{% if containsallshipments == true %} YES {% endif %}', { 'containsallshipments' => true })
   end
 end # ParsingQuirksTest

test/integration/standard_filter_test.rb

@@ -109,6 +109,10 @@ class StandardFiltersTest < Minitest::Test
     assert_raises(Liquid::ArgumentError) do
       @filters.slice('foobar', 0, "")
     end
+    assert_equal("", @filters.slice("foobar", 0, -(1 << 64)))
+    assert_equal("foobar", @filters.slice("foobar", 0, 1 << 63))
+    assert_equal("", @filters.slice("foobar", 1 << 63, 6))
+    assert_equal("", @filters.slice("foobar", -(1 << 63), 6))
   end
 
   def test_slice_on_arrays
@@ -123,6 +127,10 @@ class StandardFiltersTest < Minitest::Test
     assert_equal(%w(r), @filters.slice(input, -1))
     assert_equal(%w(), @filters.slice(input, 100, 10))
     assert_equal(%w(), @filters.slice(input, -100, 10))
+    assert_equal([], @filters.slice(input, 0, -(1 << 64)))
+    assert_equal(input, @filters.slice(input, 0, 1 << 63))
+    assert_equal([], @filters.slice(input, 1 << 63, 6))
+    assert_equal([], @filters.slice(input, -(1 << 63), 6))
   end
 
   def test_truncate
@@ -132,6 +140,8 @@ class StandardFiltersTest < Minitest::Test
     assert_equal('1234567890', @filters.truncate('1234567890'))
     assert_equal("测试...", @filters.truncate("测试测试测试测试", 5))
     assert_equal('12341', @filters.truncate("1234567890", 5, 1))
+    assert_equal("foobar", @filters.truncate("foobar", 1 << 63))
+    assert_equal("...", @filters.truncate("foobar", -(1 << 63)))
   end
 
   def test_split
@@ -227,10 +237,8 @@ class StandardFiltersTest < Minitest::Test
     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)
+    assert_equal('one two three four', @filters.truncatewords("one two three four", 1 << 31))
+    assert_equal('one...', @filters.truncatewords("one two three four", -(1 << 32)))
   end
 
   def test_strip_html
@@ -426,7 +434,7 @@ class StandardFiltersTest < Minitest::Test
   def test_map
     assert_equal([1, 2, 3, 4], @filters.map([{ "a" => 1 }, { "a" => 2 }, { "a" => 3 }, { "a" => 4 }], 'a'))
     assert_template_result('abc', "{{ ary | map:'foo' | map:'bar' }}",
-      'ary' => [{ 'foo' => { 'bar' => 'a' } }, { 'foo' => { 'bar' => 'b' } }, { 'foo' => { 'bar' => 'c' } }])
+      { 'ary' => [{ 'foo' => { 'bar' => 'a' } }, { 'foo' => { 'bar' => 'b' } }, { 'foo' => { 'bar' => 'c' } }] })
   end
 
   def test_map_doesnt_call_arbitrary_stuff
@@ -436,7 +444,7 @@ class StandardFiltersTest < Minitest::Test
 
   def test_map_calls_to_liquid
     t = TestThing.new
-    assert_template_result("woot: 1", '{{ foo | map: "whatever" }}', "foo" => [t])
+    assert_template_result("woot: 1", '{{ foo | map: "whatever" }}', { "foo" => [t] })
   end
 
   def test_map_calls_context=
@@ -451,13 +459,13 @@ class StandardFiltersTest < Minitest::Test
 
   def test_map_on_hashes
     assert_template_result("4217", '{{ thing | map: "foo" | map: "bar" }}',
-      "thing" => { "foo" => [{ "bar" => 42 }, { "bar" => 17 }] })
+      { "thing" => { "foo" => [{ "bar" => 42 }, { "bar" => 17 }] } })
   end
 
   def test_legacy_map_on_hashes_with_dynamic_key
     template = "{% assign key = 'foo' %}{{ thing | map: key | map: 'bar' }}"
     hash     = { "foo" => { "bar" => 42 } }
-    assert_template_result("42", template, "thing" => hash)
+    assert_template_result("42", template, { "thing" => hash })
   end
 
   def test_sort_calls_to_liquid
@@ -469,8 +477,8 @@ class StandardFiltersTest < Minitest::Test
   def test_map_over_proc
     drop  = TestDrop.new(value: "testfoo")
     p     = proc { drop }
-    templ = '{{ procs | map: "value" }}'
-    assert_template_result("testfoo", templ, "procs" => [p])
+    output = Liquid::Template.parse('{{ procs | map: "value" }}').render!({ "procs" => [p] })
+    assert_equal("testfoo", output)
   end
 
   def test_map_over_drops_returning_procs
@@ -482,12 +490,13 @@ class StandardFiltersTest < Minitest::Test
         "proc" => -> { "bar" },
       },
     ]
-    templ = '{{ drops | map: "proc" }}'
-    assert_template_result("foobar", templ, "drops" => drops)
+    output = Liquid::Template.parse('{{ drops | map: "proc" }}').render!({ "drops" => drops })
+    assert_equal("foobar", output)
   end
 
   def test_map_works_on_enumerables
-    assert_template_result("123", '{{ foo | map: "foo" }}', "foo" => TestEnumerable.new)
+    output = Liquid::Template.parse('{{ foo | map: "foo" }}').render!({ "foo" => TestEnumerable.new })
+    assert_equal("123", output)
   end
 
   def test_map_returns_empty_on_2d_input_array
@@ -514,16 +523,16 @@ class StandardFiltersTest < Minitest::Test
   end
 
   def test_sort_works_on_enumerables
-    assert_template_result("213", '{{ foo | sort: "bar" | map: "foo" }}', "foo" => TestEnumerable.new)
+    assert_template_result("213", '{{ foo | sort: "bar" | map: "foo" }}', { "foo" => TestEnumerable.new })
   end
 
   def test_first_and_last_call_to_liquid
-    assert_template_result('foobar', '{{ foo | first }}', 'foo' => [ThingWithToLiquid.new])
-    assert_template_result('foobar', '{{ foo | last }}', 'foo' => [ThingWithToLiquid.new])
+    assert_template_result('foobar', '{{ foo | first }}', { 'foo' => [ThingWithToLiquid.new] })
+    assert_template_result('foobar', '{{ foo | last }}', { 'foo' => [ThingWithToLiquid.new] })
   end
 
   def test_truncate_calls_to_liquid
-    assert_template_result("wo...", '{{ foo | truncate: 5 }}', "foo" => TestThing.new)
+    assert_template_result("wo...", '{{ foo | truncate: 5 }}', { "foo" => TestThing.new })
   end
 
   def test_date
@@ -597,42 +606,42 @@ class StandardFiltersTest < Minitest::Test
   end
 
   def test_strip
-    assert_template_result('ab c', "{{ source | strip }}", 'source' => " ab c  ")
-    assert_template_result('ab c', "{{ source | strip }}", 'source' => " \tab c  \n \t")
+    assert_template_result('ab c', "{{ source | strip }}", { 'source' => " ab c  " })
+    assert_template_result('ab c', "{{ source | strip }}", { 'source' => " \tab c  \n \t" })
   end
 
   def test_lstrip
-    assert_template_result('ab c  ', "{{ source | lstrip }}", 'source' => " ab c  ")
-    assert_template_result("ab c  \n \t", "{{ source | lstrip }}", 'source' => " \tab c  \n \t")
+    assert_template_result('ab c  ', "{{ source | lstrip }}", { 'source' => " ab c  " })
+    assert_template_result("ab c  \n \t", "{{ source | lstrip }}", { 'source' => " \tab c  \n \t" })
   end
 
   def test_rstrip
-    assert_template_result(" ab c", "{{ source | rstrip }}", 'source' => " ab c  ")
-    assert_template_result(" \tab c", "{{ source | rstrip }}", 'source' => " \tab c  \n \t")
+    assert_template_result(" ab c", "{{ source | rstrip }}", { 'source' => " ab c  " })
+    assert_template_result(" \tab c", "{{ source | rstrip }}", { 'source' => " \tab c  \n \t" })
   end
 
   def test_strip_newlines
-    assert_template_result('abc', "{{ source | strip_newlines }}", 'source' => "a\nb\nc")
-    assert_template_result('abc', "{{ source | strip_newlines }}", 'source' => "a\r\nb\nc")
+    assert_template_result('abc', "{{ source | strip_newlines }}", { 'source' => "a\nb\nc" })
+    assert_template_result('abc', "{{ source | strip_newlines }}", { 'source' => "a\r\nb\nc" })
   end
 
   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")
+    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
     assert_template_result("2", "{{ 1 | plus:1 }}")
     assert_template_result("2.0", "{{ '1' | plus:'1.0' }}")
 
-    assert_template_result("5", "{{ price | plus:'2' }}", 'price' => NumberLikeThing.new(3))
+    assert_template_result("5", "{{ price | plus:'2' }}", { 'price' => NumberLikeThing.new(3) })
   end
 
   def test_minus
-    assert_template_result("4", "{{ input | minus:operand }}", 'input' => 5, 'operand' => 1)
+    assert_template_result("4", "{{ input | minus:operand }}", { 'input' => 5, 'operand' => 1 })
     assert_template_result("2.3", "{{ '4.3' | minus:'2' }}")
 
-    assert_template_result("5", "{{ price | minus:'2' }}", 'price' => NumberLikeThing.new(7))
+    assert_template_result("5", "{{ price | minus:'2' }}", { 'price' => NumberLikeThing.new(7) })
   end
 
   def test_abs
@@ -655,7 +664,7 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result("7.25", "{{ 0.0725 | times:100 }}")
     assert_template_result("-7.25", '{{ "-0.0725" | times:100 }}')
     assert_template_result("7.25", '{{ "-0.0725" | times: -100 }}')
-    assert_template_result("4", "{{ price | times:2 }}", 'price' => NumberLikeThing.new(2))
+    assert_template_result("4", "{{ price | times:2 }}", { 'price' => NumberLikeThing.new(2) })
   end
 
   def test_divided_by
@@ -670,7 +679,7 @@ class StandardFiltersTest < Minitest::Test
       assert_template_result("4", "{{ 1 | modulo: 0 }}")
     end
 
-    assert_template_result("5", "{{ price | divided_by:2 }}", 'price' => NumberLikeThing.new(10))
+    assert_template_result("5", "{{ price | divided_by:2 }}", { 'price' => NumberLikeThing.new(10) })
   end
 
   def test_modulo
@@ -679,39 +688,39 @@ class StandardFiltersTest < Minitest::Test
       assert_template_result("4", "{{ 1 | modulo: 0 }}")
     end
 
-    assert_template_result("1", "{{ price | modulo:2 }}", 'price' => NumberLikeThing.new(3))
+    assert_template_result("1", "{{ price | modulo:2 }}", { 'price' => NumberLikeThing.new(3) })
   end
 
   def test_round
-    assert_template_result("5", "{{ input | round }}", 'input' => 4.6)
+    assert_template_result("5", "{{ input | round }}", { 'input' => 4.6 })
     assert_template_result("4", "{{ '4.3' | round }}")
-    assert_template_result("4.56", "{{ input | round: 2 }}", 'input' => 4.5612)
+    assert_template_result("4.56", "{{ input | round: 2 }}", { 'input' => 4.5612 })
     assert_raises(Liquid::FloatDomainError) do
       assert_template_result("4", "{{ 1.0 | divided_by: 0.0 | round }}")
     end
 
-    assert_template_result("5", "{{ price | round }}", 'price' => NumberLikeThing.new(4.6))
-    assert_template_result("4", "{{ price | round }}", 'price' => NumberLikeThing.new(4.3))
+    assert_template_result("5", "{{ price | round }}", { 'price' => NumberLikeThing.new(4.6) })
+    assert_template_result("4", "{{ price | round }}", { 'price' => NumberLikeThing.new(4.3) })
   end
 
   def test_ceil
-    assert_template_result("5", "{{ input | ceil }}", 'input' => 4.6)
+    assert_template_result("5", "{{ input | ceil }}", { 'input' => 4.6 })
     assert_template_result("5", "{{ '4.3' | ceil }}")
     assert_raises(Liquid::FloatDomainError) do
       assert_template_result("4", "{{ 1.0 | divided_by: 0.0 | ceil }}")
     end
 
-    assert_template_result("5", "{{ price | ceil }}", 'price' => NumberLikeThing.new(4.6))
+    assert_template_result("5", "{{ price | ceil }}", { 'price' => NumberLikeThing.new(4.6) })
   end
 
   def test_floor
-    assert_template_result("4", "{{ input | floor }}", 'input' => 4.6)
+    assert_template_result("4", "{{ input | floor }}", { 'input' => 4.6 })
     assert_template_result("4", "{{ '4.3' | floor }}")
     assert_raises(Liquid::FloatDomainError) do
       assert_template_result("4", "{{ 1.0 | divided_by: 0.0 | floor }}")
     end
 
-    assert_template_result("5", "{{ price | floor }}", 'price' => NumberLikeThing.new(5.4))
+    assert_template_result("5", "{{ price | floor }}", { 'price' => NumberLikeThing.new(5.4) })
   end
 
   def test_at_most
@@ -720,9 +729,9 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result("5", "{{ 5 | at_most:6 }}")
 
     assert_template_result("4.5", "{{ 4.5 | at_most:5 }}")
-    assert_template_result("5", "{{ width | at_most:5 }}", 'width' => NumberLikeThing.new(6))
-    assert_template_result("4", "{{ width | at_most:5 }}", 'width' => NumberLikeThing.new(4))
-    assert_template_result("4", "{{ 5 | at_most: width }}", 'width' => NumberLikeThing.new(4))
+    assert_template_result("5", "{{ width | at_most:5 }}", { 'width' => NumberLikeThing.new(6) })
+    assert_template_result("4", "{{ width | at_most:5 }}", { 'width' => NumberLikeThing.new(4) })
+    assert_template_result("4", "{{ 5 | at_most: width }}", { 'width' => NumberLikeThing.new(4) })
   end
 
   def test_at_least
@@ -731,9 +740,9 @@ class StandardFiltersTest < Minitest::Test
     assert_template_result("6", "{{ 5 | at_least:6 }}")
 
     assert_template_result("5", "{{ 4.5 | at_least:5 }}")
-    assert_template_result("6", "{{ width | at_least:5 }}", 'width' => NumberLikeThing.new(6))
-    assert_template_result("5", "{{ width | at_least:5 }}", 'width' => NumberLikeThing.new(4))
-    assert_template_result("6", "{{ 5 | at_least: width }}", 'width' => NumberLikeThing.new(6))
+    assert_template_result("6", "{{ width | at_least:5 }}", { 'width' => NumberLikeThing.new(6) })
+    assert_template_result("5", "{{ width | at_least:5 }}", { 'width' => NumberLikeThing.new(4) })
+    assert_template_result("6", "{{ 5 | at_least: width }}", { 'width' => NumberLikeThing.new(6) })
   end
 
   def test_append
@@ -766,8 +775,8 @@ 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))
+    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
@@ -778,8 +787,8 @@ 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))
+    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

test/integration/tags/break_tag_test.rb

@@ -9,8 +9,8 @@ class BreakTagTest < Minitest::Test
   # block
   def test_break_with_no_block
     assigns  = { 'i' => 1 }
-    markup   = '{% break %}'
-    expected = ''
+    markup   = 'before{% break %}after'
+    expected = 'before'
 
     assert_template_result(expected, markup, assigns)
   end

test/integration/tags/echo_test.rb

@@ -6,7 +6,7 @@ class EchoTest < Minitest::Test
   include Liquid
 
   def test_echo_outputs_its_input
-    assert_template_result('BAR', <<~LIQUID, 'variable-name' => 'bar')
+    assert_template_result('BAR', <<~LIQUID, { 'variable-name' => 'bar' })
       {%- echo variable-name | upcase -%}
     LIQUID
   end

test/integration/tags/for_tag_test.rb

@@ -12,10 +12,10 @@ class ForTagTest < Minitest::Test
   include Liquid
 
   def test_for
-    assert_template_result(' yo  yo  yo  yo ', '{%for item in array%} yo {%endfor%}', 'array' => [1, 2, 3, 4])
-    assert_template_result('yoyo', '{%for item in array%}yo{%endfor%}', 'array' => [1, 2])
-    assert_template_result(' yo ', '{%for item in array%} yo {%endfor%}', 'array' => [1])
-    assert_template_result('', '{%for item in array%}{%endfor%}', 'array' => [1, 2])
+    assert_template_result(' yo  yo  yo  yo ', '{%for item in array%} yo {%endfor%}', { 'array' => [1, 2, 3, 4] })
+    assert_template_result('yoyo', '{%for item in array%}yo{%endfor%}', { 'array' => [1, 2] })
+    assert_template_result(' yo ', '{%for item in array%} yo {%endfor%}', { 'array' => [1] })
+    assert_template_result('', '{%for item in array%}{%endfor%}', { 'array' => [1, 2] })
     expected = <<HERE
 
   yo
@@ -30,7 +30,7 @@ HERE
         yo
       {%endfor%}
     HERE
-    assert_template_result(expected, template, 'array' => [1, 2, 3])
+    assert_template_result(expected, template, { 'array' => [1, 2, 3] })
   end
 
   def test_for_reversed
@@ -45,30 +45,30 @@ HERE
       Template.parse('{% for i in (a..2) %}{% endfor %}').render!("a" => [1, 2])
     end
 
-    assert_template_result(' 0  1  2  3 ', '{% for item in (a..3) %} {{item}} {% endfor %}', "a" => "invalid integer")
+    assert_template_result(' 0  1  2  3 ', '{% for item in (a..3) %} {{item}} {% endfor %}', { "a" => "invalid integer" })
   end
 
   def test_for_with_variable_range
-    assert_template_result(' 1  2  3 ', '{%for item in (1..foobar) %} {{item}} {%endfor%}', "foobar" => 3)
+    assert_template_result(' 1  2  3 ', '{%for item in (1..foobar) %} {{item}} {%endfor%}', { "foobar" => 3 })
   end
 
   def test_for_with_hash_value_range
     foobar = { "value" => 3 }
-    assert_template_result(' 1  2  3 ', '{%for item in (1..foobar.value) %} {{item}} {%endfor%}', "foobar" => foobar)
+    assert_template_result(' 1  2  3 ', '{%for item in (1..foobar.value) %} {{item}} {%endfor%}', { "foobar" => foobar })
   end
 
   def test_for_with_drop_value_range
     foobar = ThingWithValue.new
-    assert_template_result(' 1  2  3 ', '{%for item in (1..foobar.value) %} {{item}} {%endfor%}', "foobar" => foobar)
+    assert_template_result(' 1  2  3 ', '{%for item in (1..foobar.value) %} {{item}} {%endfor%}', { "foobar" => foobar })
   end
 
   def test_for_with_variable
-    assert_template_result(' 1  2  3 ', '{%for item in array%} {{item}} {%endfor%}', 'array' => [1, 2, 3])
-    assert_template_result('123', '{%for item in array%}{{item}}{%endfor%}', 'array' => [1, 2, 3])
-    assert_template_result('123', '{% for item in array %}{{item}}{% endfor %}', 'array' => [1, 2, 3])
-    assert_template_result('abcd', '{%for item in array%}{{item}}{%endfor%}', 'array' => ['a', 'b', 'c', 'd'])
-    assert_template_result('a b c', '{%for item in array%}{{item}}{%endfor%}', 'array' => ['a', ' ', 'b', ' ', 'c'])
-    assert_template_result('abc', '{%for item in array%}{{item}}{%endfor%}', 'array' => ['a', '', 'b', '', 'c'])
+    assert_template_result(' 1  2  3 ', '{%for item in array%} {{item}} {%endfor%}', { 'array' => [1, 2, 3] })
+    assert_template_result('123', '{%for item in array%}{{item}}{%endfor%}', { 'array' => [1, 2, 3] })
+    assert_template_result('123', '{% for item in array %}{{item}}{% endfor %}', { 'array' => [1, 2, 3] })
+    assert_template_result('abcd', '{%for item in array%}{{item}}{%endfor%}', { 'array' => ['a', 'b', 'c', 'd'] })
+    assert_template_result('a b c', '{%for item in array%}{{item}}{%endfor%}', { 'array' => ['a', ' ', 'b', ' ', 'c'] })
+    assert_template_result('abc', '{%for item in array%}{{item}}{%endfor%}', { 'array' => ['a', '', 'b', '', 'c'] })
   end
 
   def test_for_helpers
@@ -92,9 +92,9 @@ HERE
   end
 
   def test_for_else
-    assert_template_result('+++', '{%for item in array%}+{%else%}-{%endfor%}', 'array' => [1, 2, 3])
-    assert_template_result('-',   '{%for item in array%}+{%else%}-{%endfor%}', 'array' => [])
-    assert_template_result('-',   '{%for item in array%}+{%else%}-{%endfor%}', 'array' => nil)
+    assert_template_result('+++', '{%for item in array%}+{%else%}-{%endfor%}', { 'array' => [1, 2, 3] })
+    assert_template_result('-',   '{%for item in array%}+{%else%}-{%endfor%}', { 'array' => [] })
+    assert_template_result('-',   '{%for item in array%}+{%else%}-{%endfor%}', { 'array' => nil })
   end
 
   def test_limiting
@@ -263,6 +263,19 @@ HERE
     assert_template_result(expected, markup, assigns)
   end
 
+  def test_for_with_break_after_nested_loop
+    source = <<~LIQUID.chomp
+      {% for i in (1..2) -%}
+        {% for j in (1..2) -%}
+          {{ i }}-{{ j }},
+        {%- endfor -%}
+        {% break -%}
+      {% endfor -%}
+      after
+    LIQUID
+    assert_template_result("1-1,1-2,after", source)
+  end
+
   def test_for_with_continue
     assigns = { 'array' => { 'items' => [1, 2, 3, 4, 5] } }
 
@@ -313,11 +326,11 @@ HERE
 
     assert_template_result('test string',
       '{%for val in string%}{{val}}{%endfor%}',
-      'string' => "test string")
+      { 'string' => "test string" })
 
     assert_template_result('test string',
       '{%for val in string limit:1%}{{val}}{%endfor%}',
-      'string' => "test string")
+      { 'string' => "test string" })
 
     assert_template_result('val-string-1-1-0-1-0-true-true-test string',
       '{%for val in string%}' \
@@ -330,7 +343,7 @@ HERE
       '{{forloop.first}}-' \
       '{{forloop.last}}-' \
       '{{val}}{%endfor%}',
-      'string' => "test string")
+      { 'string' => "test string" })
   end
 
   def test_for_parentloop_references_parent_loop
@@ -338,7 +351,7 @@ HERE
       '{% for inner in outer %}{% for k in inner %}' \
       '{{ forloop.parentloop.index }}.{{ forloop.index }} ' \
       '{% endfor %}{% endfor %}',
-      'outer' => [[1, 1, 1], [1, 1, 1]])
+      { 'outer' => [[1, 1, 1], [1, 1, 1]] })
   end
 
   def test_for_parentloop_nil_when_not_present
@@ -346,7 +359,7 @@ HERE
       '{% for inner in outer %}' \
       '{{ forloop.parentloop.index }}.{{ forloop.index }} ' \
       '{% endfor %}',
-      'outer' => [[1, 1, 1], [1, 1, 1]])
+      { 'outer' => [[1, 1, 1], [1, 1, 1]] })
   end
 
   def test_inner_for_over_empty_input
@@ -354,7 +367,7 @@ HERE
   end
 
   def test_blank_string_not_iterable
-    assert_template_result('', "{% for char in characters %}I WILL NOT BE OUTPUT{% endfor %}", 'characters' => '')
+    assert_template_result('', "{% for char in characters %}I WILL NOT BE OUTPUT{% endfor %}", { 'characters' => '' })
   end
 
   def test_bad_variable_naming_in_for_loop
@@ -437,30 +450,4 @@ HERE
 
     assert(context.registers[:for_stack].empty?)
   end
-
-  def test_instrument_for_offset_continue
-    assert_usage_increment('for_offset_continue') do
-      Template.parse('{% for item in items offset:continue %}{{item}}{% endfor %}')
-    end
-
-    assert_usage_increment('for_offset_continue', times: 0) do
-      Template.parse('{% for item in items offset:2 %}{{item}}{% endfor %}')
-    end
-  end
-
-  def test_instrument_forloop_drop_name
-    assigns = { 'items' => [1, 2, 3, 4, 5] }
-
-    assert_usage_increment('forloop_drop_name', times: 5) do
-      Template.parse('{% for item in items %}{{forloop.name}}{% endfor %}').render!(assigns)
-    end
-
-    assert_usage_increment('forloop_drop_name', times: 0) do
-      Template.parse('{% for item in items %}{{forloop.index}}{% endfor %}').render!(assigns)
-    end
-
-    assert_usage_increment('forloop_drop_name', times: 0) do
-      Template.parse('{% for item in items %}{{item}}{% endfor %}').render!(assigns)
-    end
-  end
 end

test/integration/tags/if_else_tag_test.rb

@@ -24,23 +24,23 @@ class IfElseTagTest < Minitest::Test
   end
 
   def test_if_boolean
-    assert_template_result(' YES ', '{% if var %} YES {% endif %}', 'var' => true)
+    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => true })
   end
 
   def test_if_or
-    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', 'a' => true, 'b' => true)
-    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', 'a' => true, 'b' => false)
-    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', 'a' => false, 'b' => true)
-    assert_template_result('',      '{% if a or b %} YES {% endif %}', 'a' => false, 'b' => false)
+    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', { 'a' => true, 'b' => true })
+    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', { 'a' => true, 'b' => false })
+    assert_template_result(' YES ', '{% if a or b %} YES {% endif %}', { 'a' => false, 'b' => true })
+    assert_template_result('',      '{% if a or b %} YES {% endif %}', { 'a' => false, 'b' => false })
 
-    assert_template_result(' YES ', '{% if a or b or c %} YES {% endif %}', 'a' => false, 'b' => false, 'c' => true)
-    assert_template_result('',      '{% if a or b or c %} YES {% endif %}', 'a' => false, 'b' => false, 'c' => false)
+    assert_template_result(' YES ', '{% if a or b or c %} YES {% endif %}', { 'a' => false, 'b' => false, 'c' => true })
+    assert_template_result('',      '{% if a or b or c %} YES {% endif %}', { 'a' => false, 'b' => false, 'c' => false })
   end
 
   def test_if_or_with_operators
-    assert_template_result(' YES ', '{% if a == true or b == true %} YES {% endif %}', 'a' => true, 'b' => true)
-    assert_template_result(' YES ', '{% if a == true or b == false %} YES {% endif %}', 'a' => true, 'b' => true)
-    assert_template_result('', '{% if a == false or b == false %} YES {% endif %}', 'a' => true, 'b' => true)
+    assert_template_result(' YES ', '{% if a == true or b == true %} YES {% endif %}', { 'a' => true, 'b' => true })
+    assert_template_result(' YES ', '{% if a == true or b == false %} YES {% endif %}', { 'a' => true, 'b' => true })
+    assert_template_result('', '{% if a == false or b == false %} YES {% endif %}', { 'a' => true, 'b' => true })
   end
 
   def test_comparison_of_strings_containing_and_or_or
@@ -66,40 +66,40 @@ class IfElseTagTest < Minitest::Test
   end
 
   def test_hash_miss_generates_false
-    assert_template_result('', '{% if foo.bar %} NO {% endif %}', 'foo' => {})
+    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => {} })
   end
 
   def test_if_from_variable
-    assert_template_result('', '{% if var %} NO {% endif %}', 'var' => false)
-    assert_template_result('', '{% if var %} NO {% endif %}', 'var' => nil)
-    assert_template_result('', '{% if foo.bar %} NO {% endif %}', 'foo' => { 'bar' => false })
-    assert_template_result('', '{% if foo.bar %} NO {% endif %}', 'foo' => {})
-    assert_template_result('', '{% if foo.bar %} NO {% endif %}', 'foo' => nil)
-    assert_template_result('', '{% if foo.bar %} NO {% endif %}', 'foo' => true)
+    assert_template_result('', '{% if var %} NO {% endif %}', { 'var' => false })
+    assert_template_result('', '{% if var %} NO {% endif %}', { 'var' => nil })
+    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => { 'bar' => false } })
+    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => {} })
+    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => nil })
+    assert_template_result('', '{% if foo.bar %} NO {% endif %}', { 'foo' => true })
 
-    assert_template_result(' YES ', '{% if var %} YES {% endif %}', 'var' => "text")
-    assert_template_result(' YES ', '{% if var %} YES {% endif %}', 'var' => true)
-    assert_template_result(' YES ', '{% if var %} YES {% endif %}', 'var' => 1)
-    assert_template_result(' YES ', '{% if var %} YES {% endif %}', 'var' => {})
-    assert_template_result(' YES ', '{% if var %} YES {% endif %}', 'var' => [])
+    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => "text" })
+    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => true })
+    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => 1 })
+    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => {} })
+    assert_template_result(' YES ', '{% if var %} YES {% endif %}', { 'var' => [] })
     assert_template_result(' YES ', '{% if "foo" %} YES {% endif %}')
-    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', 'foo' => { 'bar' => true })
-    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', 'foo' => { 'bar' => "text" })
-    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', 'foo' => { 'bar' => 1 })
-    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', 'foo' => { 'bar' => {} })
-    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', 'foo' => { 'bar' => [] })
+    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => true } })
+    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => "text" } })
+    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => 1 } })
+    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => {} } })
+    assert_template_result(' YES ', '{% if foo.bar %} YES {% endif %}', { 'foo' => { 'bar' => [] } })
 
-    assert_template_result(' YES ', '{% if var %} NO {% else %} YES {% endif %}', 'var' => false)
-    assert_template_result(' YES ', '{% if var %} NO {% else %} YES {% endif %}', 'var' => nil)
-    assert_template_result(' YES ', '{% if var %} YES {% else %} NO {% endif %}', 'var' => true)
-    assert_template_result(' YES ', '{% if "foo" %} YES {% else %} NO {% endif %}', 'var' => "text")
+    assert_template_result(' YES ', '{% if var %} NO {% else %} YES {% endif %}', { 'var' => false })
+    assert_template_result(' YES ', '{% if var %} NO {% else %} YES {% endif %}', { 'var' => nil })
+    assert_template_result(' YES ', '{% if var %} YES {% else %} NO {% endif %}', { 'var' => true })
+    assert_template_result(' YES ', '{% if "foo" %} YES {% else %} NO {% endif %}', { 'var' => "text" })
 
-    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', 'foo' => { 'bar' => false })
-    assert_template_result(' YES ', '{% if foo.bar %} YES {% else %} NO {% endif %}', 'foo' => { 'bar' => true })
-    assert_template_result(' YES ', '{% if foo.bar %} YES {% else %} NO {% endif %}', 'foo' => { 'bar' => "text" })
-    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', 'foo' => { 'notbar' => true })
-    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', 'foo' => {})
-    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', 'notfoo' => { 'bar' => true })
+    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', { 'foo' => { 'bar' => false } })
+    assert_template_result(' YES ', '{% if foo.bar %} YES {% else %} NO {% endif %}', { 'foo' => { 'bar' => true } })
+    assert_template_result(' YES ', '{% if foo.bar %} YES {% else %} NO {% endif %}', { 'foo' => { 'bar' => "text" } })
+    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', { 'foo' => { 'notbar' => true } })
+    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', { 'foo' => {} })
+    assert_template_result(' YES ', '{% if foo.bar %} NO {% else %} YES {% endif %}', { 'notfoo' => { 'bar' => true } })
   end
 
   def test_nested_if
@@ -184,7 +184,7 @@ class IfElseTagTest < Minitest::Test
     tests.each do |vals, expected|
       a, b, c = vals
       assigns = { 'a' => a, 'b' => b, 'c' => c }
-      assert_template_result(expected.to_s, tpl, assigns, assigns.to_s)
+      assert_template_result(expected.to_s, tpl, assigns, message: assigns.to_s)
     end
   end
 end

test/integration/tags/include_tag_test.rb

@@ -3,44 +3,13 @@
 require 'test_helper'
 
 class TestFileSystem
+  PARTIALS = {
+    "nested_template" => "{% include 'header' %} {% include 'body' %} {% include 'footer' %}",
+    "body" => "body {% include 'body_detail' %}",
+  }
+
   def read_template_file(template_path)
-    case template_path
-    when "product"
-      "Product: {{ product.title }} "
-
-    when "product_alias"
-      "Product: {{ product.title }} "
-
-    when "locale_variables"
-      "Locale: {{echo1}} {{echo2}}"
-
-    when "variant"
-      "Variant: {{ variant.title }}"
-
-    when "nested_template"
-      "{% include 'header' %} {% include 'body' %} {% include 'footer' %}"
-
-    when "body"
-      "body {% include 'body_detail' %}"
-
-    when "nested_product_template"
-      "Product: {{ nested_product_template.title }} {%include 'details'%} "
-
-    when "recursively_nested_template"
-      "-{% include 'recursively_nested_template' %}"
-
-    when "pick_a_source"
-      "from TestFileSystem"
-
-    when 'assignments'
-      "{% assign foo = 'bar' %}"
-
-    when 'break'
-      "{% break %}"
-
-    else
-      template_path
-    end
+    PARTIALS[template_path] || template_path
   end
 end
 
@@ -81,7 +50,11 @@ class IncludeTagTest < Minitest::Test
   include Liquid
 
   def setup
-    Liquid::Template.file_system = TestFileSystem.new
+    @default_file_system = Liquid::Template.file_system
+  end
+
+  def teardown
+    Liquid::Template.file_system = @default_file_system
   end
 
   def test_include_tag_looks_for_file_system_in_registers_first
@@ -91,60 +64,86 @@ class IncludeTagTest < Minitest::Test
 
   def test_include_tag_with
     assert_template_result("Product: Draft 151cm ",
-      "{% include 'product' with products[0] %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% include 'product' with products[0] %}",
+      { "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }] },
+      partials: { "product" => "Product: {{ product.title }} " })
   end
 
   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' }] },
+      partials: { "product_alias" => "Product: {{ product.title }} " })
   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' }] },
+      partials: { "product_alias" => "Product: {{ product.title }} " })
   end
 
   def test_include_tag_with_default_name
     assert_template_result("Product: Draft 151cm ",
-      "{% include 'product' %}", "product" => { 'title' => 'Draft 151cm' })
+      "{% include 'product' %}", { "product" => { 'title' => 'Draft 151cm' } },
+      partials: { "product" => "Product: {{ product.title }} " })
   end
 
   def test_include_tag_for
     assert_template_result("Product: Draft 151cm Product: Element 155cm ",
-      "{% include 'product' for products %}", "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }])
+      "{% include 'product' for products %}",
+      { "products" => [{ 'title' => 'Draft 151cm' }, { 'title' => 'Element 155cm' }] },
+      partials: { "product" => "Product: {{ product.title }} " })
   end
 
   def test_include_tag_with_local_variables
-    assert_template_result("Locale: test123 ", "{% include 'locale_variables' echo1: 'test123' %}")
+    assert_template_result("Locale: test123 ", "{% include 'locale_variables' echo1: 'test123' %}",
+      partials: { "locale_variables" => "Locale: {{echo1}} {{echo2}}" })
   end
 
   def test_include_tag_with_multiple_local_variables
     assert_template_result("Locale: test123 test321",
-      "{% include 'locale_variables' echo1: 'test123', echo2: 'test321' %}")
+      "{% include 'locale_variables' echo1: 'test123', echo2: 'test321' %}",
+      partials: { "locale_variables" => "Locale: {{echo1}} {{echo2}}" })
   end
 
   def test_include_tag_with_multiple_local_variables_from_context
     assert_template_result("Locale: test123 test321",
       "{% include 'locale_variables' echo1: echo1, echo2: more_echos.echo2 %}",
-      'echo1' => 'test123', 'more_echos' => { "echo2" => 'test321' })
+      { 'echo1' => 'test123', 'more_echos' => { "echo2" => 'test321' } },
+      partials: { "locale_variables" => "Locale: {{echo1}} {{echo2}}" })
   end
 
   def test_included_templates_assigns_variables
-    assert_template_result("bar", "{% include 'assignments' %}{{ foo }}")
+    assert_template_result("bar", "{% include 'assignments' %}{{ foo }}",
+      partials: { 'assignments' => "{% assign foo = 'bar' %}" })
   end
 
   def test_nested_include_tag
-    assert_template_result("body body_detail", "{% include 'body' %}")
+    partials = { "body" => "body {% include 'body_detail' %}", "body_detail" => "body_detail" }
+    assert_template_result("body body_detail", "{% include 'body' %}", partials: partials)
 
-    assert_template_result("header body body_detail footer", "{% include 'nested_template' %}")
+    partials = partials.merge({
+      "nested_template" => "{% include 'header' %} {% include 'body' %} {% include 'footer' %}",
+      "header" => "header",
+      "footer" => "footer",
+    })
+    assert_template_result("header body body_detail footer", "{% include 'nested_template' %}", partials: partials)
   end
 
   def test_nested_include_with_variable
+    partials = {
+      "nested_product_template" => "Product: {{ nested_product_template.title }} {%include 'details'%} ",
+      "details" => "details",
+    }
+
     assert_template_result("Product: Draft 151cm details ",
-      "{% include 'nested_product_template' with product %}", "product" => { "title" => 'Draft 151cm' })
+      "{% include 'nested_product_template' with product %}", { "product" => { "title" => 'Draft 151cm' } },
+      partials: partials)
 
     assert_template_result("Product: Draft 151cm details Product: Element 155cm details ",
-      "{% include 'nested_product_template' for products %}", "products" => [{ "title" => 'Draft 151cm' }, { "title" => 'Element 155cm' }])
+      "{% include 'nested_product_template' for products %}", { "products" => [{ "title" => 'Draft 151cm' }, { "title" => 'Element 155cm' }] },
+      partials: partials)
   end
 
   def test_recursively_included_template_does_not_produce_endless_loop
@@ -162,11 +161,15 @@ class IncludeTagTest < Minitest::Test
   end
 
   def test_dynamically_choosen_template
-    assert_template_result("Test123", "{% include template %}", "template" => 'Test123')
-    assert_template_result("Test321", "{% include template %}", "template" => 'Test321')
+    assert_template_result("Test123", "{% include template %}", { "template" => 'Test123' },
+      partials: { "Test123" => "Test123" })
+
+    assert_template_result("Test321", "{% include template %}", { "template" => 'Test321' },
+      partials: { "Test321" => "Test321" })
 
     assert_template_result("Product: Draft 151cm ", "{% include template for product %}",
-      "template" => 'product', 'product' => { 'title' => 'Draft 151cm' })
+      { "template" => 'product', 'product' => { 'title' => 'Draft 151cm' } },
+      partials: { "product" => "Product: {{ product.title }} " })
   end
 
   def test_include_tag_caches_second_read_of_same_partial
@@ -188,7 +191,8 @@ class IncludeTagTest < Minitest::Test
   end
 
   def test_include_tag_within_if_statement
-    assert_template_result("foo_if_true", "{% if true %}{% include 'foo_if_true' %}{% endif %}")
+    assert_template_result("foo_if_true", "{% if true %}{% include 'foo_if_true' %}{% endif %}",
+      partials: { "foo_if_true" => "foo_if_true" })
   end
 
   def test_custom_include_tag
@@ -222,6 +226,7 @@ class IncludeTagTest < Minitest::Test
   end
 
   def test_passing_options_to_included_templates
+    Liquid::Template.file_system = TestFileSystem.new
     assert_raises(Liquid::SyntaxError) do
       Template.parse("{% include template %}", error_mode: :strict).render!("template" => '{{ "X" || downcase }}')
     end
@@ -237,25 +242,35 @@ class IncludeTagTest < Minitest::Test
   end
 
   def test_render_raise_argument_error_when_template_is_undefined
-    assert_raises(Liquid::ArgumentError) do
-      template = Liquid::Template.parse('{% include undefined_variable %}')
-      template.render!
-    end
-    assert_raises(Liquid::ArgumentError) do
-      template = Liquid::Template.parse('{% include nil %}')
-      template.render!
-    end
+    assert_template_result("Liquid error (line 1): Argument error in tag 'include' - Illegal template name",
+      "{% include undefined_variable %}", render_errors: true)
+
+    assert_template_result("Liquid error (line 1): Argument error in tag 'include' - Illegal template name",
+      "{% include nil %}", render_errors: true)
+  end
+
+  def test_render_raise_argument_error_when_template_is_not_a_string
+    assert_template_result("Liquid error (line 1): Argument error in tag 'include' - Illegal template name",
+      "{% include 123 %}", render_errors: true)
   end
 
   def test_including_via_variable_value
-    assert_template_result("from TestFileSystem", "{% assign page = 'pick_a_source' %}{% include page %}")
+    assert_template_result("from TestFileSystem", "{% assign page = 'pick_a_source' %}{% include page %}",
+      partials: { "pick_a_source" => "from TestFileSystem" })
 
-    assert_template_result("Product: Draft 151cm ", "{% assign page = 'product' %}{% include page %}", "product" => { 'title' => 'Draft 151cm' })
+    partials = { "product" => "Product: {{ product.title }} " }
 
-    assert_template_result("Product: Draft 151cm ", "{% assign page = 'product' %}{% include page for foo %}", "foo" => { 'title' => 'Draft 151cm' })
+    assert_template_result("Product: Draft 151cm ", "{% assign page = 'product' %}{% include page %}",
+      { "product" => { 'title' => 'Draft 151cm' } },
+      partials: partials)
+
+    assert_template_result("Product: Draft 151cm ", "{% assign page = 'product' %}{% include page for foo %}",
+      { "foo" => { 'title' => 'Draft 151cm' } },
+      partials: partials)
   end
 
   def test_including_with_strict_variables
+    Liquid::Template.file_system = StubFileSystem.new({ "simple" => "simple" })
     template = Liquid::Template.parse("{% include 'simple' %}", error_mode: :warn)
     template.render(nil, strict_variables: true)
 
@@ -264,6 +279,7 @@ class IncludeTagTest < Minitest::Test
 
   def test_break_through_include
     assert_template_result("1", "{% for i in (1..3) %}{{ i }}{% break %}{{ i }}{% endfor %}")
-    assert_template_result("1", "{% for i in (1..3) %}{{ i }}{% include 'break' %}{{ i }}{% endfor %}")
+    assert_template_result("1", "{% for i in (1..3) %}{{ i }}{% include 'break' %}{{ i }}{% endfor %}",
+      partials: { 'break' => "{% break %}" })
   end
 end # IncludeTagTest

test/integration/tags/increment_tag_test.rb

@@ -6,20 +6,21 @@ class IncrementTagTest < Minitest::Test
   include Liquid
 
   def test_inc
-    assert_template_result('0', '{%increment port %}', {})
-    assert_template_result('0 1', '{%increment port %} {%increment port%}', {})
+    assert_template_result('0 1', '{%increment port %} {{ port }}')
+    assert_template_result(' 0 1 2', '{{port}} {%increment port %} {%increment port%} {{port}}')
     assert_template_result('0 0 1 2 1',
       '{%increment port %} {%increment starboard%} ' \
       '{%increment port %} {%increment port%} ' \
-      '{%increment starboard %}', {})
+      '{%increment starboard %}')
   end
 
   def test_dec
-    assert_template_result('9', '{%decrement port %}', 'port' => 10)
-    assert_template_result('-1 -2', '{%decrement port %} {%decrement port%}', {})
-    assert_template_result('1 5 2 2 5',
+    assert_template_result('-1 -1', '{%decrement port %} {{ port }}', { 'port' => 10 })
+    assert_template_result(' -1 -2 -2', '{{port}} {%decrement port %} {%decrement port%} {{port}}')
+    assert_template_result('0 1 2 0 3 1 1 3',
+      '{%increment starboard %} {%increment starboard%} {%increment starboard%} ' \
       '{%increment port %} {%increment starboard%} ' \
       '{%increment port %} {%decrement port%} ' \
-      '{%decrement starboard %}', 'port' => 1, 'starboard' => 5)
+      '{%decrement starboard %}')
   end
 end

test/integration/tags/liquid_tag_test.rb

@@ -6,13 +6,13 @@ class LiquidTagTest < Minitest::Test
   include Liquid
 
   def test_liquid_tag
-    assert_template_result('1 2 3', <<~LIQUID, 'array' => [1, 2, 3])
+    assert_template_result('1 2 3', <<~LIQUID, { 'array' => [1, 2, 3] })
       {%- liquid
         echo array | join: " "
       -%}
     LIQUID
 
-    assert_template_result('1 2 3', <<~LIQUID, 'array' => [1, 2, 3])
+    assert_template_result('1 2 3', <<~LIQUID, { 'array' => [1, 2, 3] })
       {%- liquid
         for value in array
           echo value
@@ -23,7 +23,7 @@ class LiquidTagTest < Minitest::Test
       -%}
     LIQUID
 
-    assert_template_result('4 8 12 6', <<~LIQUID, 'array' => [1, 2, 3])
+    assert_template_result('4 8 12 6', <<~LIQUID, { 'array' => [1, 2, 3] })
       {%- liquid
         for value in array
           assign double_value = value | times: 2

test/integration/tags/render_tag_test.rb

@@ -6,53 +6,52 @@ class RenderTagTest < Minitest::Test
   include Liquid
 
   def test_render_with_no_arguments
-    Liquid::Template.file_system = StubFileSystem.new('source' => 'rendered content')
-    assert_template_result('rendered content', '{% render "source" %}')
+    assert_template_result('rendered content', '{% render "source" %}',
+      partials: { 'source' => 'rendered content' })
   end
 
   def test_render_tag_looks_for_file_system_in_registers_first
-    file_system = StubFileSystem.new('pick_a_source' => 'from register file system')
-    assert_equal('from register file system',
-      Template.parse('{% render "pick_a_source" %}').render!({}, registers: { file_system: file_system }))
+    assert_template_result('from register file system', '{% render "pick_a_source" %}',
+      partials: { 'pick_a_source' => 'from register file system' })
   end
 
   def test_render_passes_named_arguments_into_inner_scope
-    Liquid::Template.file_system = StubFileSystem.new('product' => '{{ inner_product.title }}')
     assert_template_result('My Product', '{% render "product", inner_product: outer_product %}',
-      'outer_product' => { 'title' => 'My Product' })
+      { 'outer_product' => { 'title' => 'My Product' } },
+      partials: { 'product' => '{{ inner_product.title }}' })
   end
 
   def test_render_accepts_literals_as_arguments
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ price }}')
-    assert_template_result('123', '{% render "snippet", price: 123 %}')
+    assert_template_result('123', '{% render "snippet", price: 123 %}',
+      partials: { 'snippet' => '{{ price }}' })
   end
 
   def test_render_accepts_multiple_named_arguments
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ one }} {{ two }}')
-    assert_template_result('1 2', '{% render "snippet", one: 1, two: 2 %}')
+    assert_template_result('1 2', '{% render "snippet", one: 1, two: 2 %}',
+      partials: { 'snippet' => '{{ one }} {{ two }}' })
   end
 
   def test_render_does_not_inherit_parent_scope_variables
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ outer_variable }}')
-    assert_template_result('', '{% assign outer_variable = "should not be visible" %}{% render "snippet" %}')
+    assert_template_result('', '{% assign outer_variable = "should not be visible" %}{% render "snippet" %}',
+      partials: { 'snippet' => '{{ outer_variable }}' })
   end
 
   def test_render_does_not_inherit_variable_with_same_name_as_snippet
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{{ snippet }}')
-    assert_template_result('', "{% assign snippet = 'should not be visible' %}{% render 'snippet' %}")
+    assert_template_result('', "{% assign snippet = 'should not be visible' %}{% render 'snippet' %}",
+      partials: { 'snippet' => '{{ snippet }}' })
   end
 
   def test_render_does_not_mutate_parent_scope
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => '{% assign inner = 1 %}')
-    assert_template_result('', "{% render 'snippet' %}{{ inner }}")
+    assert_template_result('', "{% render 'snippet' %}{{ inner }}",
+      partials: { 'snippet' => '{% assign inner = 1 %}' })
   end
 
   def test_nested_render_tag
-    Liquid::Template.file_system = StubFileSystem.new(
-      'one' => "one {% render 'two' %}",
-      'two' => 'two'
-    )
-    assert_template_result('one two', "{% render 'one' %}")
+    assert_template_result('one two', "{% render 'one' %}",
+      partials: {
+        'one' => "one {% render 'two' %}",
+        'two' => 'two',
+      })
   end
 
   def test_recursively_rendered_template_does_not_produce_endless_loop
@@ -73,11 +72,7 @@ class RenderTagTest < Minitest::Test
   end
 
   def test_dynamically_choosen_templates_are_not_allowed
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => 'should not be rendered')
-
-    assert_raises(Liquid::SyntaxError) do
-      Liquid::Template.parse("{% assign name = 'snippet' %}{% render name %}")
-    end
+    assert_syntax_error("{% assign name = 'snippet' %}{% render name %}")
   end
 
   def test_include_tag_caches_second_read_of_same_partial
@@ -101,113 +96,114 @@ class RenderTagTest < Minitest::Test
   end
 
   def test_render_tag_within_if_statement
-    Liquid::Template.file_system = StubFileSystem.new('snippet' => 'my message')
-    assert_template_result('my message', '{% if true %}{% render "snippet" %}{% endif %}')
+    assert_template_result('my message', '{% if true %}{% render "snippet" %}{% endif %}',
+      partials: { 'snippet' => 'my message' })
   end
 
   def test_break_through_render
-    Liquid::Template.file_system = StubFileSystem.new('break' => '{% break %}')
-    assert_template_result('1', '{% for i in (1..3) %}{{ i }}{% break %}{{ i }}{% endfor %}')
-    assert_template_result('112233', '{% for i in (1..3) %}{{ i }}{% render "break" %}{{ i }}{% endfor %}')
+    options = { partials: { 'break' => '{% break %}' } }
+    assert_template_result('1', '{% for i in (1..3) %}{{ i }}{% break %}{{ i }}{% endfor %}', **options)
+    assert_template_result('112233', '{% for i in (1..3) %}{{ i }}{% render "break" %}{{ i }}{% endfor %}', **options)
   end
 
   def test_increment_is_isolated_between_renders
-    Liquid::Template.file_system = StubFileSystem.new('incr' => '{% increment %}')
-    assert_template_result('010', '{% increment %}{% increment %}{% render "incr" %}')
+    assert_template_result('010', '{% increment %}{% increment %}{% render "incr" %}',
+      partials: { 'incr' => '{% increment %}' })
   end
 
   def test_decrement_is_isolated_between_renders
-    Liquid::Template.file_system = StubFileSystem.new('decr' => '{% decrement %}')
-    assert_template_result('-1-2-1', '{% decrement %}{% decrement %}{% render "decr" %}')
+    assert_template_result('-1-2-1', '{% decrement %}{% decrement %}{% render "decr" %}',
+      partials: { 'decr' => '{% decrement %}' })
   end
 
   def test_includes_will_not_render_inside_render_tag
-    Liquid::Template.file_system = StubFileSystem.new(
-      'foo' => 'bar',
-      'test_include' => '{% include "foo" %}'
+    assert_template_result(
+      'Liquid error (test_include line 1): include usage is not allowed in this context',
+      '{% render "test_include" %}',
+      render_errors: true,
+      partials: {
+        'foo' => 'bar',
+        'test_include' => '{% include "foo" %}',
+      }
     )
-
-    exc = assert_raises(Liquid::DisabledError) do
-      Liquid::Template.parse('{% render "test_include" %}').render!
-    end
-    assert_equal('Liquid error: include usage is not allowed in this context', exc.message)
   end
 
   def test_includes_will_not_render_inside_nested_sibling_tags
-    Liquid::Template.file_system = StubFileSystem.new(
-      'foo' => 'bar',
-      'nested_render_with_sibling_include' => '{% render "test_include" %}{% include "foo" %}',
-      'test_include' => '{% include "foo" %}'
+    assert_template_result(
+      "Liquid error (test_include line 1): include usage is not allowed in this context" \
+        "Liquid error (nested_render_with_sibling_include line 1): include usage is not allowed in this context",
+      '{% render "nested_render_with_sibling_include" %}',
+      partials: {
+        'foo' => 'bar',
+        'nested_render_with_sibling_include' => '{% render "test_include" %}{% include "foo" %}',
+        'test_include' => '{% include "foo" %}',
+      },
+      render_errors: true
     )
-
-    output = Liquid::Template.parse('{% render "nested_render_with_sibling_include" %}').render
-    assert_equal('Liquid error: include usage is not allowed in this contextLiquid error: include usage is not allowed in this context', output)
   end
 
   def test_render_tag_with
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} ",
-      'product_alias' => "Product: {{ product.title }} ",
-    )
-
     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' }] },
+      partials: {
+        'product' => "Product: {{ product.title }} ",
+        'product_alias' => "Product: {{ product.title }} ",
+      })
   end
 
   def test_render_tag_with_alias
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} ",
-      'product_alias' => "Product: {{ product.title }} ",
-    )
-
     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' }] },
+      partials: {
+        'product' => "Product: {{ product.title }} ",
+        'product_alias' => "Product: {{ product.title }} ",
+      })
   end
 
   def test_render_tag_for_alias
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} ",
-      'product_alias' => "Product: {{ product.title }} ",
-    )
-
     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' }] },
+      partials: {
+        'product' => "Product: {{ product.title }} ",
+        'product_alias' => "Product: {{ product.title }} ",
+      })
   end
 
   def test_render_tag_for
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} ",
-      'product_alias' => "Product: {{ product.title }} ",
-    )
-
     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' }] },
+      partials: {
+        'product' => "Product: {{ product.title }} ",
+        'product_alias' => "Product: {{ product.title }} ",
+      })
   end
 
   def test_render_tag_forloop
-    Liquid::Template.file_system = StubFileSystem.new(
-      'product' => "Product: {{ product.title }} {% if forloop.first %}first{% endif %} {% if forloop.last %}last{% endif %} index:{{ forloop.index }} ",
-    )
-
     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' }] },
+      partials: {
+        'product' => "Product: {{ product.title }} {% if forloop.first %}first{% endif %} {% if forloop.last %}last{% endif %} index:{{ forloop.index }} ",
+      })
   end
 
   def test_render_tag_for_drop
-    Liquid::Template.file_system = StubFileSystem.new(
-      'loop' => "{{ value.foo }}",
-    )
-
     assert_template_result("123",
-      "{% render 'loop' for loop as value %}", "loop" => TestEnumerable.new)
+      "{% render 'loop' for loop as value %}", { "loop" => TestEnumerable.new },
+      partials: {
+        'loop' => "{{ value.foo }}",
+      })
   end
 
   def test_render_tag_with_drop
-    Liquid::Template.file_system = StubFileSystem.new(
-      'loop' => "{{ value }}",
-    )
-
     assert_template_result("TestEnumerable",
-      "{% render 'loop' with loop as value %}", "loop" => TestEnumerable.new)
+      "{% render 'loop' with loop as value %}", { "loop" => TestEnumerable.new },
+      partials: {
+        'loop' => "{{ value }}",
+      })
   end
 end

test/integration/tags/standard_tag_test.rb

@@ -36,6 +36,8 @@ class StandardTagTest < Minitest::Test
     assert_template_result('', '{%comment%}{% endif %}{%endcomment%}')
     assert_template_result('', '{% comment %}{% endwhatever %}{% endcomment %}')
     assert_template_result('', '{% comment %}{% raw %} {{%%%%}}  }} { {% endcomment %} {% comment {% endraw %} {% endcomment %}')
+    assert_template_result('', '{% comment %}{% " %}{% endcomment %}')
+    assert_template_result('', '{% comment %}{%%}{% endcomment %}')
 
     assert_template_result('foobar', 'foo{%comment%}comment{%endcomment%}bar')
     assert_template_result('foobar', 'foo{% comment %}comment{% endcomment %}bar')
@@ -71,7 +73,7 @@ class StandardTagTest < Minitest::Test
     assert_raises(SyntaxError) do
       assert_template_result('content foo content foo ',
         '{{ var2 }}{% capture %}{{ var }} foo {% endcapture %}{{ var2 }}{{ var2 }}',
-        'var' => 'content')
+        { 'var' => 'content' })
     end
   end
 
@@ -120,38 +122,38 @@ class StandardTagTest < Minitest::Test
   end
 
   def test_case_on_size
-    assert_template_result('',  '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', 'a' => [])
-    assert_template_result('1', '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', 'a' => [1])
-    assert_template_result('2', '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', 'a' => [1, 1])
-    assert_template_result('',  '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', 'a' => [1, 1, 1])
-    assert_template_result('',  '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', 'a' => [1, 1, 1, 1])
-    assert_template_result('',  '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', 'a' => [1, 1, 1, 1, 1])
+    assert_template_result('',  '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', { 'a' => [] })
+    assert_template_result('1', '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', { 'a' => [1] })
+    assert_template_result('2', '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', { 'a' => [1, 1] })
+    assert_template_result('',  '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', { 'a' => [1, 1, 1] })
+    assert_template_result('',  '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', { 'a' => [1, 1, 1, 1] })
+    assert_template_result('',  '{% case a.size %}{% when 1 %}1{% when 2 %}2{% endcase %}', { 'a' => [1, 1, 1, 1, 1] })
   end
 
   def test_case_on_size_with_else
     assert_template_result('else',
       '{% case a.size %}{% when 1 %}1{% when 2 %}2{% else %}else{% endcase %}',
-      'a' => [])
+      { 'a' => [] })
 
     assert_template_result('1',
       '{% case a.size %}{% when 1 %}1{% when 2 %}2{% else %}else{% endcase %}',
-      'a' => [1])
+      { 'a' => [1] })
 
     assert_template_result('2',
       '{% case a.size %}{% when 1 %}1{% when 2 %}2{% else %}else{% endcase %}',
-      'a' => [1, 1])
+      { 'a' => [1, 1] })
 
     assert_template_result('else',
       '{% case a.size %}{% when 1 %}1{% when 2 %}2{% else %}else{% endcase %}',
-      'a' => [1, 1, 1])
+      { 'a' => [1, 1, 1] })
 
     assert_template_result('else',
       '{% case a.size %}{% when 1 %}1{% when 2 %}2{% else %}else{% endcase %}',
-      'a' => [1, 1, 1, 1])
+      { 'a' => [1, 1, 1, 1] })
 
     assert_template_result('else',
       '{% case a.size %}{% when 1 %}1{% when 2 %}2{% else %}else{% endcase %}',
-      'a' => [1, 1, 1, 1, 1])
+      { 'a' => [1, 1, 1, 1, 1] })
   end
 
   def test_case_on_length_with_else
@@ -174,48 +176,47 @@ class StandardTagTest < Minitest::Test
 
   def test_assign_from_case
     # Example from the shopify forums
-    code     = "{% case collection.handle %}{% when 'menswear-jackets' %}{% assign ptitle = 'menswear' %}{% when 'menswear-t-shirts' %}{% assign ptitle = 'menswear' %}{% else %}{% assign ptitle = 'womenswear' %}{% endcase %}{{ ptitle }}"
-    template = Liquid::Template.parse(code)
-    assert_equal("menswear",   template.render!("collection" => { 'handle' => 'menswear-jackets' }))
-    assert_equal("menswear",   template.render!("collection" => { 'handle' => 'menswear-t-shirts' }))
-    assert_equal("womenswear", template.render!("collection" => { 'handle' => 'x' }))
-    assert_equal("womenswear", template.render!("collection" => { 'handle' => 'y' }))
-    assert_equal("womenswear", template.render!("collection" => { 'handle' => 'z' }))
+    code = "{% case collection.handle %}{% when 'menswear-jackets' %}{% assign ptitle = 'menswear' %}{% when 'menswear-t-shirts' %}{% assign ptitle = 'menswear' %}{% else %}{% assign ptitle = 'womenswear' %}{% endcase %}{{ ptitle }}"
+    assert_template_result("menswear",   code, { "collection" => { 'handle' => 'menswear-jackets' } })
+    assert_template_result("menswear",   code, { "collection" => { 'handle' => 'menswear-t-shirts' } })
+    assert_template_result("womenswear", code, { "collection" => { 'handle' => 'x' } })
+    assert_template_result("womenswear", code, { "collection" => { 'handle' => 'y' } })
+    assert_template_result("womenswear", code, { "collection" => { 'handle' => 'z' } })
   end
 
   def test_case_when_or
     code = '{% case condition %}{% when 1 or 2 or 3 %} its 1 or 2 or 3 {% when 4 %} its 4 {% endcase %}'
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 1)
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 2)
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 3)
-    assert_template_result(' its 4 ', code, 'condition' => 4)
-    assert_template_result('', code, 'condition' => 5)
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 1 })
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 2 })
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 3 })
+    assert_template_result(' its 4 ', code, { 'condition' => 4 })
+    assert_template_result('', code, { 'condition' => 5 })
 
     code = '{% case condition %}{% when 1 or "string" or null %} its 1 or 2 or 3 {% when 4 %} its 4 {% endcase %}'
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 1)
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 'string')
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => nil)
-    assert_template_result('', code, 'condition' => 'something else')
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 1 })
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 'string' })
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => nil })
+    assert_template_result('', code, { 'condition' => 'something else' })
   end
 
   def test_case_when_comma
     code = '{% case condition %}{% when 1, 2, 3 %} its 1 or 2 or 3 {% when 4 %} its 4 {% endcase %}'
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 1)
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 2)
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 3)
-    assert_template_result(' its 4 ', code, 'condition' => 4)
-    assert_template_result('', code, 'condition' => 5)
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 1 })
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 2 })
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 3 })
+    assert_template_result(' its 4 ', code, { 'condition' => 4 })
+    assert_template_result('', code, { 'condition' => 5 })
 
     code = '{% case condition %}{% when 1, "string", null %} its 1 or 2 or 3 {% when 4 %} its 4 {% endcase %}'
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 1)
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => 'string')
-    assert_template_result(' its 1 or 2 or 3 ', code, 'condition' => nil)
-    assert_template_result('', code, 'condition' => 'something else')
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 1 })
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => 'string' })
+    assert_template_result(' its 1 or 2 or 3 ', code, { 'condition' => nil })
+    assert_template_result('', code, { 'condition' => 'something else' })
   end
 
   def test_case_when_comma_and_blank_body
     code = '{% case condition %}{% when 1, 2 %} {% assign r = "result" %} {% endcase %}{{ r }}'
-    assert_template_result('result', code, 'condition' => 2)
+    assert_template_result('result', code, { 'condition' => 2 })
   end
 
   def test_assign

test/integration/tags/statements_test.rb

@@ -60,22 +60,22 @@ class StatementsTest < Minitest::Test
 
   def test_var_strings_equal
     text = ' {% if var == "hello there!" %} true {% else %} false {% endif %} '
-    assert_template_result('  true  ', text, 'var' => 'hello there!')
+    assert_template_result('  true  ', text, { 'var' => 'hello there!' })
   end
 
   def test_var_strings_are_not_equal
     text = ' {% if "hello there!" == var %} true {% else %} false {% endif %} '
-    assert_template_result('  true  ', text, 'var' => 'hello there!')
+    assert_template_result('  true  ', text, { 'var' => 'hello there!' })
   end
 
   def test_var_and_long_string_are_equal
     text = " {% if var == 'hello there!' %} true {% else %} false {% endif %} "
-    assert_template_result('  true  ', text, 'var' => 'hello there!')
+    assert_template_result('  true  ', text, { 'var' => 'hello there!' })
   end
 
   def test_var_and_long_string_are_equal_backwards
     text = " {% if 'hello there!' == var %} true {% else %} false {% endif %} "
-    assert_template_result('  true  ', text, 'var' => 'hello there!')
+    assert_template_result('  true  ', text, { 'var' => 'hello there!' })
   end
 
   # def test_is_nil
@@ -87,27 +87,27 @@ class StatementsTest < Minitest::Test
 
   def test_is_collection_empty
     text = ' {% if array == empty %} true {% else %} false {% endif %} '
-    assert_template_result('  true  ', text, 'array' => [])
+    assert_template_result('  true  ', text, { 'array' => [] })
   end
 
   def test_is_not_collection_empty
     text = ' {% if array == empty %} true {% else %} false {% endif %} '
-    assert_template_result('  false  ', text, 'array' => [1, 2, 3])
+    assert_template_result('  false  ', text, { 'array' => [1, 2, 3] })
   end
 
   def test_nil
     text = ' {% if var == nil %} true {% else %} false {% endif %} '
-    assert_template_result('  true  ', text, 'var' => nil)
+    assert_template_result('  true  ', text, { 'var' => nil })
 
     text = ' {% if var == null %} true {% else %} false {% endif %} '
-    assert_template_result('  true  ', text, 'var' => nil)
+    assert_template_result('  true  ', text, { 'var' => nil })
   end
 
   def test_not_nil
     text = ' {% if var != nil %} true {% else %} false {% endif %} '
-    assert_template_result('  true  ', text, 'var' => 1)
+    assert_template_result('  true  ', text, { 'var' => 1 })
 
     text = ' {% if var != null %} true {% else %} false {% endif %} '
-    assert_template_result('  true  ', text, 'var' => 1)
+    assert_template_result('  true  ', text, { 'var' => 1 })
   end
 end # StatementsTest

test/integration/tags/table_row_test.rb

@@ -20,47 +20,115 @@ class TableRowTest < Minitest::Test
   def test_table_row
     assert_template_result("<tr class=\"row1\">\n<td class=\"col1\"> 1 </td><td class=\"col2\"> 2 </td><td class=\"col3\"> 3 </td></tr>\n<tr class=\"row2\"><td class=\"col1\"> 4 </td><td class=\"col2\"> 5 </td><td class=\"col3\"> 6 </td></tr>\n",
       '{% tablerow n in numbers cols:3%} {{n}} {% endtablerow %}',
-      'numbers' => [1, 2, 3, 4, 5, 6])
+      { 'numbers' => [1, 2, 3, 4, 5, 6] })
 
     assert_template_result("<tr class=\"row1\">\n</tr>\n",
       '{% tablerow n in numbers cols:3%} {{n}} {% endtablerow %}',
-      'numbers' => [])
+      { 'numbers' => [] })
   end
 
   def test_table_row_with_different_cols
     assert_template_result("<tr class=\"row1\">\n<td class=\"col1\"> 1 </td><td class=\"col2\"> 2 </td><td class=\"col3\"> 3 </td><td class=\"col4\"> 4 </td><td class=\"col5\"> 5 </td></tr>\n<tr class=\"row2\"><td class=\"col1\"> 6 </td></tr>\n",
       '{% tablerow n in numbers cols:5%} {{n}} {% endtablerow %}',
-      'numbers' => [1, 2, 3, 4, 5, 6])
+      { 'numbers' => [1, 2, 3, 4, 5, 6] })
   end
 
   def test_table_col_counter
     assert_template_result("<tr class=\"row1\">\n<td class=\"col1\">1</td><td class=\"col2\">2</td></tr>\n<tr class=\"row2\"><td class=\"col1\">1</td><td class=\"col2\">2</td></tr>\n<tr class=\"row3\"><td class=\"col1\">1</td><td class=\"col2\">2</td></tr>\n",
       '{% tablerow n in numbers cols:2%}{{tablerowloop.col}}{% endtablerow %}',
-      'numbers' => [1, 2, 3, 4, 5, 6])
+      { 'numbers' => [1, 2, 3, 4, 5, 6] })
   end
 
   def test_quoted_fragment
     assert_template_result("<tr class=\"row1\">\n<td class=\"col1\"> 1 </td><td class=\"col2\"> 2 </td><td class=\"col3\"> 3 </td></tr>\n<tr class=\"row2\"><td class=\"col1\"> 4 </td><td class=\"col2\"> 5 </td><td class=\"col3\"> 6 </td></tr>\n",
       "{% tablerow n in collections.frontpage cols:3%} {{n}} {% endtablerow %}",
-      'collections' => { 'frontpage' => [1, 2, 3, 4, 5, 6] })
+      { 'collections' => { 'frontpage' => [1, 2, 3, 4, 5, 6] } })
     assert_template_result("<tr class=\"row1\">\n<td class=\"col1\"> 1 </td><td class=\"col2\"> 2 </td><td class=\"col3\"> 3 </td></tr>\n<tr class=\"row2\"><td class=\"col1\"> 4 </td><td class=\"col2\"> 5 </td><td class=\"col3\"> 6 </td></tr>\n",
       "{% tablerow n in collections['frontpage'] cols:3%} {{n}} {% endtablerow %}",
-      'collections' => { 'frontpage' => [1, 2, 3, 4, 5, 6] })
+      { 'collections' => { 'frontpage' => [1, 2, 3, 4, 5, 6] } })
   end
 
   def test_enumerable_drop
     assert_template_result("<tr class=\"row1\">\n<td class=\"col1\"> 1 </td><td class=\"col2\"> 2 </td><td class=\"col3\"> 3 </td></tr>\n<tr class=\"row2\"><td class=\"col1\"> 4 </td><td class=\"col2\"> 5 </td><td class=\"col3\"> 6 </td></tr>\n",
       '{% tablerow n in numbers cols:3%} {{n}} {% endtablerow %}',
-      'numbers' => ArrayDrop.new([1, 2, 3, 4, 5, 6]))
+      { 'numbers' => ArrayDrop.new([1, 2, 3, 4, 5, 6]) })
   end
 
   def test_offset_and_limit
     assert_template_result("<tr class=\"row1\">\n<td class=\"col1\"> 1 </td><td class=\"col2\"> 2 </td><td class=\"col3\"> 3 </td></tr>\n<tr class=\"row2\"><td class=\"col1\"> 4 </td><td class=\"col2\"> 5 </td><td class=\"col3\"> 6 </td></tr>\n",
       '{% tablerow n in numbers cols:3 offset:1 limit:6%} {{n}} {% endtablerow %}',
-      'numbers' => [0, 1, 2, 3, 4, 5, 6, 7])
+      { 'numbers' => [0, 1, 2, 3, 4, 5, 6, 7] })
   end
 
   def test_blank_string_not_iterable
-    assert_template_result("<tr class=\"row1\">\n</tr>\n", "{% tablerow char in characters cols:3 %}I WILL NOT BE OUTPUT{% endtablerow %}", 'characters' => '')
+    assert_template_result("<tr class=\"row1\">\n</tr>\n",
+      "{% tablerow char in characters cols:3 %}I WILL NOT BE OUTPUT{% endtablerow %}",
+      { 'characters' => '' })
+  end
+
+  def test_cols_nil_constant_same_as_evaluated_nil_expression
+    expect = "<tr class=\"row1\">\n" \
+      "<td class=\"col1\">false</td>" \
+      "<td class=\"col2\">false</td>" \
+      "</tr>\n"
+
+    assert_template_result(expect,
+      "{% tablerow i in (1..2) cols:nil %}{{ tablerowloop.col_last }}{% endtablerow %}")
+
+    assert_template_result(expect,
+      "{% tablerow i in (1..2) cols:var %}{{ tablerowloop.col_last }}{% endtablerow %}",
+      { "var" => nil })
+  end
+
+  def test_tablerow_loop_drop_attributes
+    template = <<~LIQUID.chomp
+      {% tablerow i in (1...2) %}
+      col: {{ tablerowloop.col }}
+      col0: {{ tablerowloop.col0 }}
+      col_first: {{ tablerowloop.col_first }}
+      col_last: {{ tablerowloop.col_last }}
+      first: {{ tablerowloop.first }}
+      index: {{ tablerowloop.index }}
+      index0: {{ tablerowloop.index0 }}
+      last: {{ tablerowloop.last }}
+      length: {{ tablerowloop.length }}
+      rindex: {{ tablerowloop.rindex }}
+      rindex0: {{ tablerowloop.rindex0 }}
+      row: {{ tablerowloop.row }}
+      {% endtablerow %}
+    LIQUID
+
+    expected_output = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">
+      col: 1
+      col0: 0
+      col_first: true
+      col_last: false
+      first: true
+      index: 1
+      index0: 0
+      last: false
+      length: 2
+      rindex: 2
+      rindex0: 1
+      row: 1
+      </td><td class="col2">
+      col: 2
+      col0: 1
+      col_first: false
+      col_last: true
+      first: false
+      index: 2
+      index0: 1
+      last: true
+      length: 2
+      rindex: 1
+      rindex0: 0
+      row: 1
+      </td></tr>
+    OUTPUT
+
+    assert_template_result(expected_output, template)
   end
 end

test/integration/tags/unless_else_tag_test.rb

@@ -19,10 +19,10 @@ class UnlessElseTagTest < Minitest::Test
   end
 
   def test_unless_in_loop
-    assert_template_result('23', '{% for i in choices %}{% unless i %}{{ forloop.index }}{% endunless %}{% endfor %}', 'choices' => [1, nil, false])
+    assert_template_result('23', '{% for i in choices %}{% unless i %}{{ forloop.index }}{% endunless %}{% endfor %}', { 'choices' => [1, nil, false] })
   end
 
   def test_unless_else_in_loop
-    assert_template_result(' TRUE  2  3 ', '{% for i in choices %}{% unless i %} {{ forloop.index }} {% else %} TRUE {% endunless %}{% endfor %}', 'choices' => [1, nil, false])
+    assert_template_result(' TRUE  2  3 ', '{% for i in choices %}{% unless i %} {{ forloop.index }} {% else %} TRUE {% endunless %}{% endfor %}', { 'choices' => [1, nil, false] })
   end
 end # UnlessElseTest

test/integration/template_test.rb

@@ -315,13 +315,11 @@ class TemplateTest < Minitest::Test
   end
 
   def test_using_range_literal_works_as_expected
-    t = Template.parse("{% assign foo = (x..y) %}{{ foo }}")
-    result = t.render('x' => 1, 'y' => 5)
-    assert_equal('1..5', result)
+    source = "{% assign foo = (x..y) %}{{ foo }}"
+    assert_template_result("1..5", source, { "x" => 1, "y" => 5 })
 
-    t = Template.parse("{% assign nums = (x..y) %}{% for num in nums %}{{ num }}{% endfor %}")
-    result = t.render('x' => 1, 'y' => 5)
-    assert_equal('12345', result)
+    source = "{% assign nums = (x..y) %}{% for num in nums %}{{ num }}{% endfor %}"
+    assert_template_result("12345", source, { "x" => 1, "y" => 5 })
   end
 
   def test_source_string_subclass

test/integration/trim_mode_test.rb

@@ -530,14 +530,9 @@ class TrimModeTest < Minitest::Test
   end
 
   def test_pre_trim_blank_preceding_text
-    template = Liquid::Template.parse("\n{%- raw %}{% endraw %}")
-    assert_equal("", template.render)
-
-    template = Liquid::Template.parse("\n{%- if true %}{% endif %}")
-    assert_equal("", template.render)
-
-    template = Liquid::Template.parse("{{ 'B' }} \n{%- if true %}C{% endif %}")
-    assert_equal("BC", template.render)
+    assert_template_result("", "\n{%- raw %}{% endraw %}")
+    assert_template_result("", "\n{%- if true %}{% endif %}")
+    assert_template_result("BC", "{{ 'B' }} \n{%- if true %}C{% endif %}")
   end
 
   def test_bug_compatible_pre_trim

test/integration/variable_test.rb

@@ -6,81 +6,76 @@ class VariableTest < Minitest::Test
   include Liquid
 
   def test_simple_variable
-    template = Template.parse(%({{test}}))
-    assert_equal('worked', template.render!('test' => 'worked'))
-    assert_equal('worked wonderfully', template.render!('test' => 'worked wonderfully'))
+    assert_template_result('worked', "{{test}}", { 'test' => 'worked' })
+    assert_template_result('worked wonderfully', "{{test}}", { 'test' => 'worked wonderfully' })
   end
 
   def test_variable_render_calls_to_liquid
-    assert_template_result('foobar', '{{ foo }}', 'foo' => ThingWithToLiquid.new)
+    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))
+    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('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))
+    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))
+    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'))
+    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'))
-    assert_equal('  worked wonderfully  ', template.render!('test' => 'worked wonderfully'))
+    assert_template_result("  worked  ", "  {{ test }}  ", { "test" => "worked" })
+    assert_template_result("  worked wonderfully  ", "  {{ test }}  ", { "test" => "worked wonderfully" })
   end
 
   def test_expression_with_whitespace_in_square_brackets
-    assert_template_result('result', "{{ a[ 'b' ] }}", 'a' => { 'b' => 'result' })
-    assert_template_result('result', "{{ a[ [ 'b' ] ] }}", 'b' => 'c', 'a' => { 'c' => 'result' })
+    assert_template_result('result', "{{ a[ 'b' ] }}", { 'a' => { 'b' => 'result' } })
+    assert_template_result('result', "{{ a[ [ 'b' ] ] }}", { 'b' => 'c', 'a' => { 'c' => 'result' } })
   end
 
   def test_ignore_unknown
-    template = Template.parse(%({{ test }}))
-    assert_equal('', template.render!)
+    assert_template_result("", "{{ test }}")
   end
 
   def test_using_blank_as_variable_name
-    template = Template.parse("{% assign foo = blank %}{{ foo }}")
-    assert_equal('', template.render!)
+    assert_template_result("", "{% assign foo = blank %}{{ foo }}")
   end
 
   def test_using_empty_as_variable_name
-    template = Template.parse("{% assign foo = empty %}{{ foo }}")
-    assert_equal('', template.render!)
+    assert_template_result("", "{% assign foo = empty %}{{ foo }}")
   end
 
   def test_hash_scoping
-    assert_template_result('worked', "{{ test.test }}", 'test' => { 'test' => 'worked' })
-    assert_template_result('worked', "{{ test . test }}", 'test' => { 'test' => 'worked' })
+    assert_template_result('worked', "{{ test.test }}", { 'test' => { 'test' => 'worked' } })
+    assert_template_result('worked', "{{ test . test }}", { 'test' => { 'test' => 'worked' } })
   end
 
   def test_false_renders_as_false
-    assert_equal('false', Template.parse("{{ foo }}").render!('foo' => false))
-    assert_equal('false', Template.parse("{{ false }}").render!)
+    assert_template_result("false", "{{ foo }}", { 'foo' => false })
+    assert_template_result("false", "{{ false }}")
   end
 
   def test_nil_renders_as_empty_string
-    assert_equal('', Template.parse("{{ nil }}").render!)
-    assert_equal('cat', Template.parse("{{ nil | append: 'cat' }}").render!)
+    assert_template_result("", "{{ nil }}")
+    assert_template_result("cat", "{{ nil | append: 'cat' }}")
   end
 
   def test_preset_assigns
@@ -121,18 +116,18 @@ class VariableTest < Minitest::Test
   end
 
   def test_multiline_variable
-    assert_equal('worked', Template.parse("{{\ntest\n}}").render!('test' => 'worked'))
+    assert_template_result("worked", "{{\ntest\n}}", { "test" => "worked" })
   end
 
   def test_render_symbol
-    assert_template_result('bar', '{{ foo }}', 'foo' => :bar)
+    assert_template_result('bar', '{{ foo }}', { 'foo' => :bar })
   end
 
   def test_dynamic_find_var
-    assert_template_result('bar', '{{ [key] }}', 'key' => 'foo', 'foo' => 'bar')
+    assert_template_result('bar', '{{ [key] }}', { 'key' => 'foo', 'foo' => 'bar' })
   end
 
   def test_raw_value_variable
-    assert_template_result('bar', '{{ [key] }}', 'key' => 'foo', 'foo' => 'bar')
+    assert_template_result('bar', '{{ [key] }}', { 'key' => 'foo', 'foo' => 'bar' })
   end
 end

test/test_helper.rb

@@ -37,23 +37,54 @@ module Minitest
   module Assertions
     include Liquid
 
-    def assert_template_result(expected, template, assigns = {}, message = nil)
-      assert_equal(expected, Template.parse(template, line_numbers: true).render!(assigns), message)
+    def assert_template_result(
+      expected, template, assigns = {},
+      message: nil, partials: nil, error_mode: nil, render_errors: false
+    )
+      template = Liquid::Template.parse(template, line_numbers: true, error_mode: error_mode&.to_sym)
+      file_system = StubFileSystem.new(partials || {})
+      registers = Liquid::Registers.new(file_system: file_system)
+      context = Liquid::Context.build(static_environments: assigns, rethrow_errors: !render_errors, registers: registers)
+      output = template.render(context)
+      assert_equal(expected, output, message)
     end
 
-    def assert_template_result_matches(expected, template, assigns = {}, message = nil)
-      return assert_template_result(expected, template, assigns, message) unless expected.is_a?(Regexp)
+    if ENV['LIQUID_MIGRATOR']
+      puts "-- Liquid Migrator Enabled"
 
-      assert_match(expected, Template.parse(template, line_numbers: true).render!(assigns), message)
+      alias_method(:assert_template_result_without_migrator, :assert_template_result)
+
+      def assert_template_result(expected, source, assigns = {}, error_mode: nil, partials: nil, **kwargs)
+        migrated_source = Liquid::Template.migrate(source, line_numbers: true, error_mode: error_mode&.to_sym)
+        assert_no_migration(migrated_source)
+        if partials
+          migrated_partials = {}
+          partials.each do |name, partial|
+            new_partial = Liquid::Template.migrate(partial, line_numbers: true, error_mode: error_mode&.to_sym)
+            assert_no_migration(new_partial)
+            migrated_partials[name] = new_partial
+          end
+        end
+        assert_template_result_without_migrator(expected, migrated_source, assigns,
+          error_mode: 'strict', partials: migrated_partials, **kwargs)
+      end
     end
 
-    def assert_match_syntax_error(match, template, assigns = {})
+    def assert_match_syntax_error(match, template, error_mode: nil)
       exception = assert_raises(Liquid::SyntaxError) do
-        Template.parse(template, line_numbers: true).render(assigns)
+        Template.parse(template, line_numbers: true, error_mode: error_mode&.to_sym).render
       end
       assert_match(match, exception.message)
     end
 
+    def assert_syntax_error(template, error_mode: nil)
+      assert_match_syntax_error("", template, error_mode: error_mode)
+    end
+
+    def assert_no_migration(source)
+      assert_equal(source, Liquid::Template.migrate(source))
+    end
+
     def assert_usage_increment(name, times: 1)
       old_method = Liquid::Usage.method(:increment)
       calls = 0

test/unit/migrate_unit_test.rb

@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class MigrateUnitTest < Minitest::Test
+  def test_migrate_preserves_valid_markup
+    [
+      "{{a}}",
+      " {{- \ta\n -}} ",
+      "{{a.b['c'].d[5]|default:6,allow_false:true|truncate:7,'..'}}",
+      "{{ a . b [ 'c' ] . d [ 5 ] | default : 6 , allow_false : true | truncate :  4 , '..'  }}",
+      "{%assign x=a.b['c'].d[5]|default:6,allow_false:true|truncate:7,'..'%}",
+      "{% assign x =\na . b [ 'c' ] . d [ 5 ] | default : 6 , allow_false : true | truncate :  4 , '..'  %}",
+      "{% if a and b > c %}A{% elsif d or f contains g %}B{% else %}C{% endif %}",
+      <<~LIQUID,
+        {% liquid
+          if x > 0
+            assign x = x | plus: 1
+
+          endif
+        %}
+      LIQUID
+    ].each do |source|
+      assert_no_migration(source)
+    end
+  end
+
+  def test_migrate_variable
+    with_error_mode(:lax) do
+      assert_migration({
+        %({{ ,|"' }}) => "{{  }}", # no MarkupWithQuotedFragment match, skipping characters
+        %({{ ,|"' 123 }}) => "{{  123 }}", # MarkupWithQuotedFragment skipped characters
+        "{{,-2}}" => "{{ -2}}", # preserve separators when removing ignored characters
+        "{{  12 34  }}" => "{{  12  }}", # no FilterMarkupRegex match, skipping characters
+        "{{ -12 34 | abs }}" => "{{ -12 | abs }}", # FilterMarkupRegex skipped characters
+        %({{ -12 | '" abs }}) => "{{ -12 |  abs }}", # FilterParser skipped characters
+        "{{ -1 | abs ' plus: 1 }}" => "{{ -1 | abs | plus: 1 }}", # FilterParser unexpected separator
+        "{{ -1 | ! abs }}" => "{{ -1 | abs }}", # ignored non-word characters preceding filter name
+        "{{ 'a' | append WAT: 'b' }}" => "{{ 'a' | append : 'b' }}", # FilterArgsRegex skipped characters
+        "{{ '!' | replace, '!': '?' }}" => "{{ '!' | replace: '!', '?' }}", # FilterArgsRegex unexpected separators
+        "{{ -a.1b }}" => "{{ ['-a']['1b'] }}", # quote separators when removing ignored characters
+      })
+    end
+  end
+
+  def test_migrate_expression
+    with_error_mode(:lax) do
+      assert_migration({
+        "{{ (1.9...2.8) }}" => "{{ (1..2) }}", # apply constant range coercion
+        "{{ 1.2.3.4 }}" => "{{ 1.2 }}", # multiple periods allowed by FLOATS_REGEX, truncated by to_f
+        "{{ 1. }}" => "{{ 1.0 }}", # FLOATS_REGEX didn't require digits after the period
+        "{{ .empty }}" => "{{ ['empty'] }}", # skipped character prevents exact literal lookup
+      })
+    end
+  end
+
+  def test_migrate_variable_lookup
+    with_error_mode(:lax) do
+      assert_migration({
+        "{{@a[b].c@}}" => "{{ a[b].c }}", # VariableParser skipped characters
+        "{{ a!b$c }}" => "{{ a.b.c }}", # VariableParser unexpected separators
+      })
+    end
+  end
+
+  def test_migrate_assign
+    with_error_mode(:lax) do
+      assert_migration({
+        "{% assign!a = b!%}" => "{% assign a = b %}", # Syntax skipped characters
+        "{% assign a = @b ! %}" => "{% assign a =  b %}", # Variable skipped characters
+        "{% assign|x=1 %}" => "{% assign x=1 %}", # ensure tag name separated from markup
+      })
+    end
+  end
+
+  def test_lax_migrate_if
+    with_error_mode(:lax) do
+      assert_migration({
+        "{% if@a@%}Y{% endif %}" => "{% if a %}Y{% endif %}", # Syntax skipped character
+        "{% if &a contains^b and *c %}A{% elsif %d or$e %}B{% endif %}" =>
+          "{% if  a contains b and  c %}A{% elsif  d or e %}B{% endif %}", # test more expressions
+        "{% if b 1 %}Y{% endif %}" => "{% if b  %}Y{% endif %}", # missing operator with right operand
+        "{% if c == %}Y{% endif %}" => "{% if c == nil %}Y{% endif %}", # operator with missing right operand
+        "{% if!a!%}T{% endif %}" => "{% if a %}T{% endif %}", # VariableParser skipped characters
+        "{% if!%}T{% endif %}" => "{% if nil %}T{% endif %}", # VariableParser skipping all characters
+      })
+    end
+  end
+
+  def test_migrate_liquid_tag
+    with_error_mode(:lax) do
+      source = <<~LIQUID
+        {% liquid
+          assign ! a = 1
+          assign a = @b !
+        %}
+      LIQUID
+      expect = <<~LIQUID
+        {% liquid
+          assign  a = 1
+          assign a =  b
+        %}
+      LIQUID
+      assert_migration({ source => expect })
+    end
+  end
+
+  def test_migrate_for
+    with_error_mode(:lax) do
+      assert_migration({
+        # VariableLookup ignored character
+        "{% for i in !array %}x{% endfor %}" => "{% for i in  array %}x{% endfor %}",
+
+        # TagAttributes scanned over separators
+        "{% for i in array|offset: 1|limit: 5 %}x{% endfor %}" => "{% for i in array, offset: 1, limit: 5 %}x{% endfor %}",
+
+        # TagAttributes scans all the markup, which can overlap with what Syntax already matched
+        "{% for i in foo.offset: wat %}x{% endfor %}" => "{% for i in foo.offset , offset: wat %}x{% endfor %}",
+      })
+    end
+  end
+
+  private
+
+  def assert_migration(source_to_expected_output_hash)
+    source_to_expected_output_hash.each do |source, expect|
+      message = "source: #{source.inspect}"
+      assert_equal(expect, Liquid::Template.migrate(source), message)
+      assert_no_migration(expect)
+      assert_equal(Liquid::Template.parse(expect, parse_mode: :strict).render!, Liquid::Template.parse(source).render!, message)
+    end
+  end
+end

test/unit/parse_tree_visitor_test.rb

@@ -236,6 +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, [