Add targeted tests for byte-walking fast paths

36 tests covering the three optimization sites:

Expression.parse_number (13 tests):
  - Simple integers, negatives, floats, trailing dots
  - Multi-dot truncation (1.2.3 → 1.2)
  - Rejection of non-numeric input and trailing alpha (1.2.3a)

Expression.parse strip guard (7 tests):
  - Leading, trailing, both-sides whitespace
  - No-strip-needed case (no allocation)
  - Null byte stripping (matches String#strip behavior)

VariableLookup.simple_lookup? (8 tests):
  - Accepts: single names, dotted chains, question marks, hyphens
  - Rejects: brackets, empty, leading/trailing dots, double dots

VariableLookup fast path equivalence (7 tests):
  - name/lookups/command_flags match for simple and deep chains
  - Bracket inputs fall through to regex path correctly

BlockBody.try_parse_tag_token (10 tests):
  - Simple tags, whitespace control variants ({%-, -%}, both)
  - No-markup tags, hash comments, newline counting
  - Hyphenated names stop at hyphen (matching TagName = /\w+/)
  - Malformed tokens return nil (fallback to FullToken regex)

.github/dependabot.yaml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: weekly

.github/workflows/liquid.yml

@@ -1,5 +1,5 @@
 name: Liquid
-on: [push, pull_request]
+on: [push]
 
 env:
   BUNDLE_JOBS: 4
@@ -9,30 +9,34 @@ jobs:
   test:
     runs-on: ubuntu-latest
     strategy:
+      fail-fast: false
       matrix:
         entry:
-          - { ruby: 3.0, allowed-failure: false } # minimum supported
-          - { ruby: 3.2, allowed-failure: false }
-          - { ruby: 3.3, allowed-failure: false }
-          - { ruby: 3.3, allowed-failure: false }
-          - { ruby: 3.4, allowed-failure: false } # latest
-          - {
-              ruby: 3.4,
-              allowed-failure: false,
-              rubyopt: "--enable-frozen-string-literal",
-            }
+          - { ruby: 3.3, allowed-failure: false } # minimum supported
           - { ruby: 3.4, allowed-failure: false, rubyopt: "--yjit" }
-          - { ruby: ruby-head, allowed-failure: false }
+          - { ruby: 4.0, allowed-failure: false } # latest stable
           - {
-              ruby: ruby-head,
+              ruby: 4.0,
               allowed-failure: false,
               rubyopt: "--enable-frozen-string-literal",
             }
-          - { ruby: ruby-head, allowed-failure: false, rubyopt: "--yjit" }
-    name: Test Ruby ${{ matrix.entry.ruby }}
+          - { ruby: 4.0, allowed-failure: false, rubyopt: "--yjit" }
+          - { ruby: 4.0, allowed-failure: false, rubyopt: "--zjit" }
+          - { ruby: truffleruby, allowed-failure: false }
+
+          # Head can have failures due to being in development
+          - { ruby: head, allowed-failure: true }
+          - {
+              ruby: head,
+              allowed-failure: true,
+              rubyopt: "--enable-frozen-string-literal",
+            }
+          - { ruby: head, allowed-failure: true, rubyopt: "--yjit" }
+          - { ruby: head, allowed-failure: true, rubyopt: "--zjit" }
+    name: Test Ruby ${{ matrix.entry.ruby }} ${{ matrix.entry.rubyopt }} --${{ matrix.entry.allowed-failure && 'allowed-failure' || 'strict' }}
     steps:
-      - uses: actions/checkout@v3
-      - uses: ruby/setup-ruby@v1
+      - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
+      - uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1.295.0
         with:
           ruby-version: ${{ matrix.entry.ruby }}
           bundler-cache: true
@@ -42,11 +46,28 @@ jobs:
         env:
           RUBYOPT: ${{ matrix.entry.rubyopt }}
 
+  spec:
+    runs-on: ubuntu-latest
+    env:
+      BUNDLE_WITH: spec
+    steps:
+      - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
+      - uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1.295.0
+        with:
+          bundler-cache: true
+          bundler: latest
+      - name: Run liquid-spec for all adapters
+        run: |
+          for adapter in spec/*.rb; do
+            echo "=== Running $adapter ==="
+            bundle exec liquid-spec run "$adapter" --no-max-failures
+          done
+
   memory_profile:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
-      - uses: ruby/setup-ruby@v1
+      - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
+      - uses: ruby/setup-ruby@319994f95fa847cf3fb3cd3dbe89f6dcde9f178f # v1.295.0
         with:
           bundler-cache: true
       - run: bundle exec rake memory_profile:run

.rubocop_todo.yml

@@ -174,7 +174,16 @@ Style/WordArray:
 
 # Offense count: 117
 # This cop supports safe auto-correction (--auto-correct).
-# Configuration parameters: AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, AllowedPatterns, IgnoredPatterns.
+# Configuration parameters: AllowHeredoc, AllowURI, URISchemes, AllowCopDirectives, AllowedPatterns.
 # URISchemes: http, https
 Layout/LineLength:
   Max: 260
+
+Naming/PredicatePrefix:
+  Enabled: false
+
+# Offense count: 1
+# This is intentional - early return from begin/rescue in assignment context
+Lint/NoReturnInBeginEndBlocks:
+  Exclude:
+    - 'lib/liquid/standardfilters.rb'

Gemfile

@@ -25,7 +25,13 @@ group :development do
 end
 
 group :test do
-  gem 'rubocop', '~> 1.61.0'
-  gem 'rubocop-shopify', '~> 2.12.0', require: false
+  gem 'benchmark'
+  gem 'rubocop', '~> 1.82.0'
+  gem 'rubocop-shopify', '~> 2.18.0', require: false
   gem 'rubocop-performance', require: false
 end
+
+group :spec do
+  gem 'liquid-spec', github: 'Shopify/liquid-spec', branch: 'main'
+  gem 'activesupport', require: false
+end

History.md

@@ -1,6 +1,17 @@
 # Liquid Change Log
 
-## 5.8.1 (unreleased)
+## 5.11.0
+* Revert the Inline Snippets tag (#2001), treat its inclusion in the latest Liquid release as a bug, and allow for feedback on RFC#1916 to better support Liquid developers [Guilherme Carreiro]
+* Rename the `:rigid` error mode to `:strict2` and display a warning when users attempt to use the `:rigid` mode [Guilherme Carreiro]
+
+## 5.10.0
+* Introduce support for Inline Snippets [Julia Boutin]
+
+## 5.9.0
+* Introduce `:rigid` error mode for stricter, safer parsing of all tags [CP Clermont, Guilherme Carreiro]
+
+## 5.8.7
+* Expose body content in the `Doc` tag [James Meng]
 
 ## 5.8.1
 

README.md

@@ -99,14 +99,14 @@ Setting the error mode of Liquid lets you specify how strictly you want your tem
 Normally the parser is very lax and will accept almost anything without error. Unfortunately this can make
 it very hard to debug and can lead to unexpected behaviour.
 
-Liquid also comes with a stricter parser that can be used when editing templates to give better error messages
+Liquid also comes with different parsers that can be used when editing templates to give better error messages
 when templates are invalid. You can enable this new parser like this:
 
 ```ruby
-Liquid::Environment.default.error_mode = :strict
-Liquid::Environment.default.error_mode = :strict # Raises a SyntaxError when invalid syntax is used
-Liquid::Environment.default.error_mode = :warn # Adds strict errors to template.errors but continues as normal
-Liquid::Environment.default.error_mode = :lax # The default mode, accepts almost anything.
+Liquid::Environment.default.error_mode = :strict2 # Raises a SyntaxError when invalid syntax is used in all tags
+Liquid::Environment.default.error_mode = :strict  # Raises a SyntaxError when invalid syntax is used in some tags
+Liquid::Environment.default.error_mode = :warn    # Adds strict errors to template.errors but continues as normal
+Liquid::Environment.default.error_mode = :lax     # The default mode, accepts almost anything.
 ```
 
 If you want to set the error mode only on specific templates you can pass `:error_mode` as an option to `parse`:

Rakefile

@@ -33,7 +33,7 @@ task :rubocop do
   end
 end
 
-desc('runs test suite with both strict and lax parsers')
+desc('runs test suite with lax, strict, and strict2 parsers')
 task :test do
   ENV['LIQUID_PARSER_MODE'] = 'lax'
   Rake::Task['base_test'].invoke
@@ -42,6 +42,10 @@ task :test do
   Rake::Task['base_test'].reenable
   Rake::Task['base_test'].invoke
 
+  ENV['LIQUID_PARSER_MODE'] = 'strict2'
+  Rake::Task['base_test'].reenable
+  Rake::Task['base_test'].invoke
+
   if RUBY_ENGINE == 'ruby' || RUBY_ENGINE == 'truffleruby'
     ENV['LIQUID_PARSER_MODE'] = 'lax'
     Rake::Task['integration_test'].reenable
@@ -50,6 +54,10 @@ task :test do
     ENV['LIQUID_PARSER_MODE'] = 'strict'
     Rake::Task['integration_test'].reenable
     Rake::Task['integration_test'].invoke
+
+    ENV['LIQUID_PARSER_MODE'] = 'strict2'
+    Rake::Task['integration_test'].reenable
+    Rake::Task['integration_test'].invoke
   end
 end
 
@@ -80,8 +88,13 @@ namespace :benchmark do
     ruby "./performance/benchmark.rb strict"
   end
 
-  desc "Run the liquid benchmark with both lax and strict parsing"
-  task run: [:lax, :strict]
+  desc "Run the liquid benchmark with strict2 parsing"
+  task :strict2 do
+    ruby "./performance/benchmark.rb strict2"
+  end
+
+  desc "Run the liquid benchmark with lax, strict, and strict2 parsing"
+  task run: [:lax, :strict, :strict2]
 
   desc "Run unit benchmarks"
   namespace :unit do
@@ -135,3 +148,9 @@ end
 task :console do
   exec 'irb -I lib -r liquid'
 end
+
+desc('run liquid-spec suite across all adapters')
+task :spec do
+  adapters = Dir['./spec/*.rb'].join(',')
+  sh "bundle exec liquid-spec matrix --adapters=#{adapters} --reference=ruby_liquid"
+end

bin/render

@@ -0,0 +1,46 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require 'bundler/setup'
+require 'liquid'
+
+class VirtualFileSystem
+  def initialize
+    snippet_1 = <<~LIQUID
+      <h1>
+        {{- greating | default: 'Hello' }}, {{ name | default: 'world' -}}!
+      </h1>
+    LIQUID
+    snippet_2 = <<~LIQUID
+      {%- for i in (1..5) -%}
+        > {{ i }}
+      {%- endfor -%}
+    LIQUID
+
+    @templates = {
+      'snippet-1' => snippet_1,
+      'snippet-2' => snippet_2,
+    }
+  end
+
+  def read_template_file(key)
+    @templates[key] || raise(Liquid::FileSystemError, "No such template '#{key}'")
+  end
+end
+
+def source
+  File.read(ARGV[0])
+rescue StandardError
+  'Usage: bin/render example/server/templates/index.liquid'
+end
+
+def assigns
+  {
+    'date' => Time.now,
+  }
+end
+
+puts Liquid::Template
+  .parse(source, error_mode: :strict2)
+  .tap { |t| t.registers[:file_system] = VirtualFileSystem.new }
+  .render(assigns)

lib/liquid.rb

@@ -52,6 +52,7 @@ end
 require "liquid/version"
 require "liquid/deprecations"
 require "liquid/const"
+require "liquid/byte_tables"
 require 'liquid/standardfilters'
 require 'liquid/file_system'
 require 'liquid/parser_switching'

lib/liquid/block_body.rb

@@ -130,16 +130,21 @@ module Liquid
         case
         when token.start_with?(TAGSTART)
           whitespace_handler(token, parse_context)
-          unless token =~ FullToken
+          # rubocop:disable Metrics/BlockNesting
+          fast = try_parse_tag_token(token)
+          if fast
+            tag_name, markup, newlines = fast
+          elsif token =~ FullToken
+            tag_name = Regexp.last_match(2)
+            markup   = Regexp.last_match(4)
+            newlines = parse_context.line_number ? Regexp.last_match(1).count("\n") + Regexp.last_match(3).count("\n") : 0
+          else
             return handle_invalid_tag_token(token, parse_context, &block)
           end
-          tag_name = Regexp.last_match(2)
-          markup   = Regexp.last_match(4)
+          # rubocop:enable Metrics/BlockNesting
 
-          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")
+          if parse_context.line_number && newlines > 0
+            parse_context.line_number += newlines
           end
 
           if tag_name == 'liquid'
@@ -260,6 +265,77 @@ module Liquid
       BlockBody.raise_missing_variable_terminator(token, parse_context)
     end
 
+    # Fast path for parsing "{%[-] tag_name markup [-]%}" tag tokens.
+    # Returns [tag_name, markup, newline_count] or nil.
+    #
+    # Accepts tokens where:
+    #   - Tag name is '#' or starts with [a-zA-Z_] followed by \w chars
+    #     (matching TagName = /#|\w+/ exactly — no hyphens, no '?' suffix)
+    #   - Whitespace is spaces, tabs, newlines, \r, \f, \v
+    #   - Whitespace control dashes are at positions 2 and len-3
+    # Rejects (returns nil → caller falls back to FullToken regex):
+    #   - Tokens shorter than "{%x%}" (4 bytes)
+    #   - Tag names starting with a digit (valid in FullToken but rare)
+    #   - Any structure the byte-walk can't confidently parse
+    # Fallback: nil return triggers the original `token =~ FullToken` regex
+    #   match in parse_for_document, preserving identical behavior for any
+    #   input the fast path doesn't handle.
+    def try_parse_tag_token(token)
+      len = token.bytesize
+      pos = 2 # skip "{%"
+      return if pos >= len
+
+      pos += 1 if token.getbyte(pos) == ByteTables::DASH
+      newline_count = 0
+
+      # Skip whitespace before tag name, count newlines
+      while pos < len
+        b = token.getbyte(pos)
+        if b == ByteTables::NEWLINE
+          pos += 1
+          newline_count += 1
+        elsif ByteTables::WHITESPACE[b]
+          pos += 1
+        else
+          break
+        end
+      end
+      return if pos >= len
+
+      # Scan tag name: '#' or \w+ (matching TagName = /#|\w+/)
+      name_start = pos
+      b = token.getbyte(pos)
+      if b == ByteTables::HASH
+        pos += 1
+      elsif ByteTables::IDENT_START[b]
+        pos += 1
+        pos += 1 while pos < len && ByteTables::WORD[token.getbyte(pos)]
+      else
+        return
+      end
+      tag_name = token.byteslice(name_start, pos - name_start)
+
+      # Skip whitespace after tag name, count newlines
+      while pos < len
+        b = token.getbyte(pos)
+        if b == ByteTables::NEWLINE
+          pos += 1
+          newline_count += 1
+        elsif ByteTables::WHITESPACE[b]
+          pos += 1
+        else
+          break
+        end
+      end
+
+      # Markup: everything up to optional '-' before '%}'
+      markup_end = len - 2 # skip '%}'
+      markup_end -= 1 if markup_end > pos && token.getbyte(markup_end - 1) == ByteTables::DASH
+      markup = pos >= markup_end ? "" : token.byteslice(pos, markup_end - pos)
+
+      [tag_name, markup, newline_count]
+    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/byte_tables.rb

@@ -0,0 +1,48 @@
+# frozen_string_literal: true
+
+module Liquid
+  # Pre-computed 256-entry boolean lookup tables for byte classification.
+  # Built once at load time; used as TABLE[byte] — a single array index
+  # instead of 3-5 comparison operators per check.
+  module ByteTables
+    # [a-zA-Z_] — valid first byte of an identifier
+    IDENT_START = Array.new(256, false).tap do |t|
+      (97..122).each { |b| t[b] = true }  # a-z
+      (65..90).each  { |b| t[b] = true }  # A-Z
+      t[95] = true # _
+    end.freeze
+
+    # [a-zA-Z0-9_-] — valid continuation byte of an identifier
+    IDENT_CONT = Array.new(256, false).tap do |t|
+      (97..122).each { |b| t[b] = true }  # a-z
+      (65..90).each  { |b| t[b] = true }  # A-Z
+      (48..57).each  { |b| t[b] = true }  # 0-9
+      t[95] = true                          # _
+      t[45] = true                          # -
+    end.freeze
+
+    # [a-zA-Z0-9_] — \w equivalent (no hyphen), for tag name scanning
+    WORD = Array.new(256, false).tap do |t|
+      (97..122).each { |b| t[b] = true }  # a-z
+      (65..90).each  { |b| t[b] = true }  # A-Z
+      (48..57).each  { |b| t[b] = true }  # 0-9
+      t[95] = true # _
+    end.freeze
+
+    # [0-9] — ASCII digit
+    DIGIT = Array.new(256, false).tap do |t|
+      (48..57).each { |b| t[b] = true }
+    end.freeze
+
+    # Matches bytes removed by Ruby's String#strip: \x00, \t, \n, \v, \f, \r, space
+    WHITESPACE = Array.new(256, false).tap do |t|
+      [0, 9, 10, 11, 12, 13, 32].each { |b| t[b] = true }
+    end.freeze
+
+    # Byte constants for delimiters and punctuation
+    NEWLINE = 10
+    DASH    = 45  # '-'
+    DOT     = 46  # '.'
+    HASH    = 35  # '#'
+  end
+end

lib/liquid/condition.rb

@@ -48,8 +48,8 @@ module Liquid
       @@operators
     end
 
-    def self.parse_expression(parse_context, markup)
-      @@method_literals[markup] || parse_context.parse_expression(markup)
+    def self.parse_expression(parse_context, markup, safe: false)
+      @@method_literals[markup] || parse_context.parse_expression(markup, safe: safe)
     end
 
     attr_reader :attachment, :child_condition
@@ -113,24 +113,67 @@ module Liquid
 
     def equal_variables(left, right)
       if left.is_a?(MethodLiteral)
-        if right.respond_to?(left.method_name)
-          return right.send(left.method_name)
-        else
-          return nil
-        end
+        return call_method_literal(left, right)
       end
 
       if right.is_a?(MethodLiteral)
-        if left.respond_to?(right.method_name)
-          return left.send(right.method_name)
-        else
-          return nil
-        end
+        return call_method_literal(right, left)
       end
 
       left == right
     end
 
+    def call_method_literal(literal, value)
+      method_name = literal.method_name
+
+      # If the object responds to the method (e.g., ActiveSupport is loaded), use it
+      if value.respond_to?(method_name)
+        value.send(method_name)
+      else
+        # Emulate ActiveSupport's blank?/empty? to make Liquid invariant
+        # to whether ActiveSupport is loaded or not
+        case method_name
+        when :blank?
+          liquid_blank?(value)
+        when :empty?
+          liquid_empty?(value)
+        else
+          false
+        end
+      end
+    end
+
+    # Implement blank? semantics matching ActiveSupport
+    # blank? returns true for nil, false, empty strings, whitespace-only strings,
+    # empty arrays, and empty hashes
+    def liquid_blank?(value)
+      case value
+      when NilClass, FalseClass
+        true
+      when TrueClass, Numeric
+        false
+      when String
+        # Blank if empty or whitespace only (matches ActiveSupport)
+        value.empty? || value.match?(/\A\s*\z/)
+      when Array, Hash
+        value.empty?
+      else
+        # Fall back to empty? if available, otherwise false
+        value.respond_to?(:empty?) ? value.empty? : false
+      end
+    end
+
+    # Implement empty? semantics
+    # Note: nil is NOT empty. empty? checks if a collection has zero elements.
+    def liquid_empty?(value)
+      case value
+      when String, Array, Hash
+        value.empty?
+      else
+        value.respond_to?(:empty?) ? value.empty? : false
+      end
+    end
+
     def interpret_condition(left, right, op, context)
       # If the operator is empty this means that the decision statement is just
       # a single variable. We can just poll this variable from the context and
@@ -154,8 +197,8 @@ module Liquid
     end
 
     def deprecated_default_context
-      warn("DEPRECATION WARNING: Condition#evaluate without a context argument is deprecated" \
-        " and will be removed from Liquid 6.0.0.")
+      warn("DEPRECATION WARNING: Condition#evaluate without a context argument is deprecated " \
+        "and will be removed from Liquid 6.0.0.")
       Context.new
     end
 

lib/liquid/context.rb

@@ -184,7 +184,7 @@ module Liquid
     end
 
     def key?(key)
-      self[key] != nil
+      find_variable(key, raise_on_not_found: false) != nil
     end
 
     def evaluate(object)

lib/liquid/drop.rb

@@ -31,7 +31,7 @@ module Liquid
 
     # Catch all for the method
     def liquid_method_missing(method)
-      return nil unless @context&.strict_variables
+      return unless @context&.strict_variables
       raise Liquid::UndefinedDropMethod, "undefined method #{method}"
     end
 

lib/liquid/environment.rb

@@ -34,7 +34,7 @@ module Liquid
       # @param file_system The default file system that is used
       #  to load templates from.
       # @param error_mode [Symbol] The default error mode for all templates
-      #  (either :strict, :warn, or :lax).
+      #  (either :strict2, :strict, :warn, or :lax).
       # @param exception_renderer [Proc] The exception renderer that is used to
       #   render exceptions.
       # @yieldparam environment [Environment] The environment instance that is being built.

lib/liquid/expression.rb

@@ -16,22 +16,27 @@ module Liquid
       '-' => VariableLookup.parse("-", nil).freeze,
     }.freeze
 
-    DOT = ".".ord
-    ZERO = "0".ord
-    NINE = "9".ord
-    DASH = "-".ord
-
     # Use an atomic group (?>...) to avoid pathological backtracing from
     # malicious input as described in https://github.com/Shopify/liquid/issues/1357
     RANGES_REGEX = /\A\(\s*(?>(\S+)\s*\.\.)\s*(\S+)\s*\)\z/
-    INTEGER_REGEX = /\A(-?\d+)\z/
-    FLOAT_REGEX = /\A(-?\d+)\.\d+\z/
 
     class << self
+      def safe_parse(parser, ss = StringScanner.new(""), cache = nil)
+        parse(parser.expression, ss, cache)
+      end
+
       def parse(markup, ss = StringScanner.new(""), cache = nil)
         return unless markup
 
-        markup = markup.strip # markup can be a frozen string
+        # Guard: only call .strip when the first or last byte is whitespace.
+        # String#strip always allocates a new String, even when there's nothing
+        # to strip. ByteTables::WHITESPACE matches the same bytes that strip
+        # removes (space, \t, \n, \v, \f, \r, \x00). When neither end has
+        # whitespace, we skip the call and avoid ~4,464 allocations per compile.
+        first = markup.getbyte(0)
+        if first && (ByteTables::WHITESPACE[first] || ByteTables::WHITESPACE[markup.getbyte(markup.bytesize - 1)])
+          markup = markup.strip
+        end
 
         if (markup.start_with?('"') && markup.end_with?('"')) ||
           (markup.start_with?("'") && markup.end_with?("'"))
@@ -51,7 +56,7 @@ module Liquid
       end
 
       def inner_parse(markup, ss, cache)
-        if (markup.start_with?("(") && markup.end_with?(")")) && markup =~ RANGES_REGEX
+        if markup.start_with?("(") && markup.end_with?(")") && markup =~ RANGES_REGEX
           return RangeLookup.parse(
             Regexp.last_match(1),
             Regexp.last_match(2),
@@ -67,56 +72,74 @@ module Liquid
         end
       end
 
-      def parse_number(markup, ss)
-        # check if the markup is simple integer or float
-        case markup
-        when INTEGER_REGEX
-          return Integer(markup, 10)
-        when FLOAT_REGEX
-          return markup.to_f
-        end
+      # Fast path for number parsing. Accepts:
+      #   - Simple integers: "42", "-7"
+      #   - Simple floats: "3.14", "-0.5"
+      #   - Multi-dot floats (truncated at second dot): "1.2.3" → 1.2
+      #   - Trailing-dot floats: "123." → 123.0
+      # Rejects (returns nil → caller treats as VariableLookup):
+      #   - Non-numeric input: "hello", ""
+      #   - Inputs with non-digit/non-dot bytes after the number: "1.2.3a"
+      # Fallback: nil return causes caller to fall through to VariableLookup.parse,
+      #   which is the same path the old regex-based code took on non-match.
+      def parse_number(markup, _ss = nil)
+        len = markup.bytesize
+        return if len == 0
 
-        ss.string = markup
-        # the first byte must be a digit or  a dash
-        byte = ss.scan_byte
+        pos = 0
+        first = markup.getbyte(pos)
 
-        return false if byte != DASH && (byte < ZERO || byte > NINE)
+        if first == ByteTables::DASH
+          pos += 1
+          return if pos >= len
+          return unless ByteTables::DIGIT[markup.getbyte(pos)]
 
-        if byte == DASH
-          peek_byte = ss.peek_byte
-
-          # if it starts with a dash, the next byte must be a digit
-          return false if peek_byte.nil? || !(peek_byte >= ZERO && peek_byte <= NINE)
-        end
-
-        # The markup could be a float with multiple dots
-        first_dot_pos = nil
-        num_end_pos = nil
-
-        while (byte = ss.scan_byte)
-          return false if byte != DOT && (byte < ZERO || byte > NINE)
-
-          # we found our number and now we are just scanning the rest of the string
-          next if num_end_pos
-
-          if byte == DOT
-            if first_dot_pos.nil?
-              first_dot_pos = ss.pos
-            else
-              # we found another dot, so we know that the number ends here
-              num_end_pos = ss.pos - 1
-            end
-          end
-        end
-
-        num_end_pos = markup.length if ss.eos?
-
-        if num_end_pos
-          # number ends with a number "123.123"
-          markup.byteslice(0, num_end_pos).to_f
+          pos += 1
+        elsif ByteTables::DIGIT[first]
+          pos += 1
         else
-          # number ends with a dot "123."
-          markup.byteslice(0, first_dot_pos).to_f
+          return
+        end
+
+        # Scan digits
+        pos += 1 while pos < len && ByteTables::DIGIT[markup.getbyte(pos)]
+
+        # Consumed everything = simple integer
+        return Integer(markup, 10) if pos == len
+
+        # Check for dot — three float cases:
+        #   1. Simple float:   "123.456"   → markup.to_f
+        #   2. Multi-dot:      "1.2.3.4"   → truncate at second dot → 1.2
+        #   3. Trailing dot:   "123."      → truncate before dot → 123.0
+        return unless markup.getbyte(pos) == ByteTables::DOT
+
+        dot_pos = pos
+        pos += 1
+        digit_start = pos
+        pos += 1 while pos < len && ByteTables::DIGIT[markup.getbyte(pos)]
+
+        if pos > digit_start && pos == len
+          # Case 1: simple float like "123.456"
+          markup.to_f
+        elsif pos > digit_start
+          # Case 2: multi-dot like "1.2.3.4" — find where the numeric
+          # portion ends. Reject if any non-digit, non-dot byte is found
+          # (e.g. "1.2.3a" → nil, matching the old regex-based behavior).
+          num_end = nil
+          check = pos
+          while check < len
+            b = markup.getbyte(check)
+            if b == ByteTables::DOT
+              num_end ||= check
+            elsif !ByteTables::DIGIT[b]
+              return
+            end
+            check += 1
+          end
+          markup.byteslice(0, num_end || len).to_f
+        else
+          # Case 3: trailing dot like "123."
+          markup.byteslice(0, dot_pos).to_f
         end
       end
     end

lib/liquid/i18n.rb

@@ -28,7 +28,7 @@ module Liquid
     def interpolate(name, vars)
       name.gsub(/%\{(\w+)\}/) do
         # raise TranslationError, "Undefined key #{$1} for interpolation in translation #{name}"  unless vars[$1.to_sym]
-        (vars[Regexp.last_match(1).to_sym]).to_s
+        vars[Regexp.last_match(1).to_sym].to_s
       end
     end
 

lib/liquid/locales/en.yml

@@ -20,6 +20,7 @@
       invalid_template_encoding: "Invalid template encoding"
       render: "Syntax error in tag 'render' - Template name must be a quoted string"
       table_row: "Syntax Error in 'table_row loop' - Valid syntax: table_row [item] in [collection] cols=3"
+      table_row_invalid_attribute: "Invalid attribute '%{attribute}' in tablerow loop. Valid attributes are cols, limit, offset, and range"
       tag_never_closed: "'%{block_name}' tag was never closed"
       tag_termination: "Tag '%{token}' was not properly terminated with regexp: %{tag_end}"
       unexpected_else: "%{block_name} tag does not expect 'else' tag"

lib/liquid/parse_context.rb

@@ -50,7 +50,22 @@ module Liquid
       )
     end
 
-    def parse_expression(markup)
+    def safe_parse_expression(parser)
+      Expression.safe_parse(parser, @string_scanner, @expression_cache)
+    end
+
+    def parse_expression(markup, safe: false)
+      if !safe && @error_mode == :strict2
+        # parse_expression is a widely used API. To maintain backward
+        # compatibility while raising awareness about strict2 parser standards,
+        # the safe flag supports API users make a deliberate decision.
+        #
+        # In strict2 mode, markup MUST come from a string returned by the parser
+        # (e.g., parser.expression). We're not calling the parser here to
+        # prevent redundant parser overhead.
+        raise Liquid::InternalError, "unsafe parse_expression cannot be used in strict2 mode"
+      end
+
       Expression.parse(markup, @string_scanner, @expression_cache)
     end
 

lib/liquid/parser_switching.rb

@@ -2,10 +2,25 @@
 
 module Liquid
   module ParserSwitching
+    # Do not use this.
+    #
+    # It's basically doing the same thing the {#parse_with_selected_parser},
+    # except this will try the strict parser regardless of the error mode,
+    # and fall back to the lax parser if the error mode is lax or warn,
+    # except when in strict2 mode where it uses the strict2 parser.
+    #
+    # @deprecated Use {#parse_with_selected_parser} instead.
     def strict_parse_with_error_mode_fallback(markup)
+      return strict2_parse_with_error_context(markup) if strict2_mode?
+
       strict_parse_with_error_context(markup)
     rescue SyntaxError => e
       case parse_context.error_mode
+      when :rigid
+        rigid_warn
+        raise
+      when :strict2
+        raise
       when :strict
         raise
       when :warn
@@ -16,11 +31,13 @@ module Liquid
 
     def parse_with_selected_parser(markup)
       case parse_context.error_mode
-      when :strict then strict_parse_with_error_context(markup)
-      when :lax    then lax_parse(markup)
+      when :rigid   then rigid_warn && strict2_parse_with_error_context(markup)
+      when :strict2 then strict2_parse_with_error_context(markup)
+      when :strict  then strict_parse_with_error_context(markup)
+      when :lax     then lax_parse(markup)
       when :warn
         begin
-          strict_parse_with_error_context(markup)
+          strict2_parse_with_error_context(markup)
         rescue SyntaxError => e
           parse_context.warnings << e
           lax_parse(markup)
@@ -28,8 +45,24 @@ module Liquid
       end
     end
 
+    def strict2_mode?
+      parse_context.error_mode == :strict2 || parse_context.error_mode == :rigid
+    end
+
     private
 
+    def rigid_warn
+      Deprecations.warn(':rigid', ':strict2')
+    end
+
+    def strict2_parse_with_error_context(markup)
+      strict2_parse(markup)
+    rescue SyntaxError => e
+      e.line_number    = line_number
+      e.markup_context = markup_context(markup)
+      raise e
+    end
+
     def strict_parse_with_error_context(markup)
       strict_parse(markup)
     rescue SyntaxError => e

lib/liquid/resource_limits.rb

@@ -2,24 +2,39 @@
 
 module Liquid
   class ResourceLimits
-    attr_accessor :render_length_limit, :render_score_limit, :assign_score_limit
-    attr_reader :render_score, :assign_score
+    attr_accessor :render_length_limit,
+      :render_score_limit,
+      :assign_score_limit,
+      :cumulative_render_score_limit,
+      :cumulative_assign_score_limit
+    attr_reader :render_score,
+      :assign_score,
+      :cumulative_render_score,
+      :cumulative_assign_score
 
     def initialize(limits)
-      @render_length_limit = limits[:render_length_limit]
-      @render_score_limit  = limits[:render_score_limit]
-      @assign_score_limit  = limits[:assign_score_limit]
+      @render_length_limit           = limits[:render_length_limit]
+      @render_score_limit            = limits[:render_score_limit]
+      @assign_score_limit            = limits[:assign_score_limit]
+      @cumulative_render_score_limit = limits[:cumulative_render_score_limit]
+      @cumulative_assign_score_limit = limits[:cumulative_assign_score_limit]
+      @cumulative_render_score = 0
+      @cumulative_assign_score = 0
       reset
     end
 
     def increment_render_score(amount)
       @render_score += amount
+      @cumulative_render_score += amount
       raise_limits_reached if @render_score_limit && @render_score > @render_score_limit
+      raise_limits_reached if @cumulative_render_score_limit && @cumulative_render_score > @cumulative_render_score_limit
     end
 
     def increment_assign_score(amount)
       @assign_score += amount
+      @cumulative_assign_score += amount
       raise_limits_reached if @assign_score_limit && @assign_score > @assign_score_limit
+      raise_limits_reached if @cumulative_assign_score_limit && @cumulative_assign_score > @cumulative_assign_score_limit
     end
 
     # update either render_length or assign_score based on whether or not the writes are captured
@@ -47,6 +62,8 @@ module Liquid
       @reached_limit = false
       @last_capture_length = nil
       @render_score = @assign_score = 0
+      raise_limits_reached if @cumulative_render_score_limit && @cumulative_render_score > @cumulative_render_score_limit
+      raise_limits_reached if @cumulative_assign_score_limit && @cumulative_assign_score > @cumulative_assign_score_limit
     end
 
     def with_capture

lib/liquid/standardfilters.rb

@@ -8,10 +8,19 @@ module Liquid
     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
+    supports_64bit_indices = begin
+      [][1 << 33, 1 << 33]
+      true
+    rescue RangeError
+      false
+    end
+
+    INDEX_RANGE = if supports_64bit_indices
+      (-(1 << 63))..((1 << 63) - 1)
+    else
+      (-(1 << 31))..((1 << 31) - 1)
+    end
+    private_constant :INDEX_RANGE
 
     HTML_ESCAPE = {
       '&' => '&amp;',
@@ -214,11 +223,11 @@ module Liquid
           Utils.to_s(input).slice(offset, length) || ''
         end
       rescue RangeError
-        if I64_RANGE.cover?(length) && I64_RANGE.cover?(offset)
+        if INDEX_RANGE.cover?(length) && INDEX_RANGE.cover?(offset)
           raise # unexpected error
         end
-        offset = offset.clamp(I64_RANGE)
-        length = length.clamp(I64_RANGE)
+        offset = offset.clamp(INDEX_RANGE)
+        length = length.clamp(INDEX_RANGE)
         retry
       end
     end
@@ -293,6 +302,19 @@ module Liquid
       input.split(pattern)
     end
 
+    # @liquid_public_docs
+    # @liquid_type filter
+    # @liquid_category string
+    # @liquid_summary
+    #   Removes leading and trailing whitespace and collapses consecutive whitespace to a single space.
+    # @liquid_syntax string | squish
+    # @liquid_return [string]
+    def squish(input)
+      return if input.nil?
+
+      Utils.to_s(input).strip.gsub(/\s+/, ' ')
+    end
+
     # @liquid_public_docs
     # @liquid_type filter
     # @liquid_category string
@@ -768,6 +790,8 @@ module Liquid
     # @liquid_syntax array | first
     # @liquid_return [untyped]
     def first(array)
+      # ActiveSupport returns "" for empty strings, not nil
+      return array[0] || "" if array.is_a?(String)
       array.first if array.respond_to?(:first)
     end
 
@@ -779,6 +803,8 @@ module Liquid
     # @liquid_syntax array | last
     # @liquid_return [untyped]
     def last(array)
+      # ActiveSupport returns "" for empty strings, not nil
+      return array[-1] || "" if array.is_a?(String)
       array.last if array.respond_to?(:last)
     end
 

lib/liquid/tag.rb

@@ -68,8 +68,12 @@ module Liquid
 
     private
 
-    def parse_expression(markup)
-      parse_context.parse_expression(markup)
+    def safe_parse_expression(parser)
+      parse_context.safe_parse_expression(parser)
+    end
+
+    def parse_expression(markup, safe: false)
+      parse_context.parse_expression(markup, safe: safe)
     end
   end
 end

lib/liquid/tags/assign.rb

@@ -9,6 +9,10 @@ module Liquid
   #   Creates a new variable.
   # @liquid_description
   #   You can create variables of any [basic type](/docs/api/liquid/basics#types), [object](/docs/api/liquid/objects), or object property.
+  #
+  #   > Caution:
+  #   > Predefined Liquid objects can be overridden by variables with the same name.
+  #   > To make sure that you can access all Liquid objects, make sure that your variable name doesn't match a predefined object's name.
   # @liquid_syntax
   #   {% assign variable_name = value %}
   # @liquid_syntax_keyword variable_name The name of the variable being created.

lib/liquid/tags/capture.rb

@@ -9,6 +9,10 @@ module Liquid
   #   Creates a new variable with a string value.
   # @liquid_description
   #   You can create complex strings with Liquid logic and variables.
+  #
+  #   > Caution:
+  #   > Predefined Liquid objects can be overridden by variables with the same name.
+  #   > To make sure that you can access all Liquid objects, make sure that your variable name doesn't match a predefined object's name.
   # @liquid_syntax
   #   {% capture variable %}
   #     value

lib/liquid/tags/case.rb

@@ -31,12 +31,7 @@ module Liquid
     def initialize(tag_name, markup, options)
       super
       @blocks = []
-
-      if markup =~ Syntax
-        @left = parse_expression(Regexp.last_match(1))
-      else
-        raise SyntaxError, options[:locale].t("errors.syntax.case")
-      end
+      parse_with_selected_parser(markup)
     end
 
     def parse(tokens)
@@ -91,9 +86,50 @@ module Liquid
 
     private
 
+    def strict2_parse(markup)
+      parser = @parse_context.new_parser(markup)
+      @left = safe_parse_expression(parser)
+      parser.consume(:end_of_string)
+    end
+
+    def strict_parse(markup)
+      lax_parse(markup)
+    end
+
+    def lax_parse(markup)
+      if markup =~ Syntax
+        @left = parse_expression(Regexp.last_match(1))
+      else
+        raise SyntaxError, options[:locale].t("errors.syntax.case")
+      end
+    end
+
     def record_when_condition(markup)
       body = new_body
 
+      if strict2_mode?
+        parse_strict2_when(markup, body)
+      else
+        parse_lax_when(markup, body)
+      end
+    end
+
+    def parse_strict2_when(markup, body)
+      parser = @parse_context.new_parser(markup)
+
+      loop do
+        expr = Condition.parse_expression(parse_context, parser.expression, safe: true)
+        block = Condition.new(@left, '==', expr)
+        block.attach(body)
+        @blocks << block
+
+        break unless parser.id?('or') || parser.consume?(:comma)
+      end
+
+      parser.consume(:end_of_string)
+    end
+
+    def parse_lax_when(markup, body)
       while markup
         unless markup =~ WhenSyntax
           raise SyntaxError, options[:locale].t("errors.syntax.case_invalid_when")

lib/liquid/tags/cycle.rb

@@ -17,23 +17,13 @@ module Liquid
   class Cycle < Tag
     SimpleSyntax = /\A#{QuotedFragment}+/o
     NamedSyntax  = /\A(#{QuotedFragment})\s*\:\s*(.*)/om
+    UNNAMED_CYCLE_PATTERN = /\w+:0x\h{8}/
 
     attr_reader :variables
 
     def initialize(tag_name, markup, options)
       super
-      case markup
-      when NamedSyntax
-        @variables = variables_from_string(Regexp.last_match(2))
-        @name      = parse_expression(Regexp.last_match(1))
-        @is_named = true
-      when SimpleSyntax
-        @variables = variables_from_string(markup)
-        @name      = @variables.to_s
-        @is_named = !@name.match?(/\w+:0x\h{8}/)
-      else
-        raise SyntaxError, options[:locale].t("errors.syntax.cycle")
-      end
+      parse_with_selected_parser(markup)
     end
 
     def named?
@@ -65,19 +55,82 @@ module Liquid
 
     private
 
+    # cycle [name:] expression(, expression)*
+    def strict2_parse(markup)
+      p = @parse_context.new_parser(markup)
+
+      @variables = []
+
+      raise SyntaxError, options[:locale].t("errors.syntax.cycle") if p.look(:end_of_string)
+
+      first_expression = safe_parse_expression(p)
+      if p.look(:colon)
+        # cycle name: expr1, expr2, ...
+        @name = first_expression
+        @is_named = true
+        p.consume(:colon)
+        # After the colon, parse the first variable (required for named cycles)
+        @variables << maybe_dup_lookup(safe_parse_expression(p))
+      else
+        # cycle expr1, expr2, ...
+        @variables << maybe_dup_lookup(first_expression)
+      end
+
+      # Parse remaining comma-separated expressions
+      while p.consume?(:comma)
+        break if p.look(:end_of_string)
+
+        @variables << maybe_dup_lookup(safe_parse_expression(p))
+      end
+
+      p.consume(:end_of_string)
+
+      unless @is_named
+        @name = @variables.to_s
+        @is_named = !@name.match?(UNNAMED_CYCLE_PATTERN)
+      end
+    end
+
+    def strict_parse(markup)
+      lax_parse(markup)
+    end
+
+    def lax_parse(markup)
+      case markup
+      when NamedSyntax
+        @variables = variables_from_string(Regexp.last_match(2))
+        @name      = parse_expression(Regexp.last_match(1))
+        @is_named = true
+      when SimpleSyntax
+        @variables = variables_from_string(markup)
+        @name      = @variables.to_s
+        @is_named = !@name.match?(UNNAMED_CYCLE_PATTERN)
+      else
+        raise SyntaxError, options[:locale].t("errors.syntax.cycle")
+      end
+    end
+
     def variables_from_string(markup)
       markup.split(',').collect do |var|
         var =~ /\s*(#{QuotedFragment})\s*/o
         next unless Regexp.last_match(1)
 
-        # Expression Parser returns cached objects, and we need to dup them to
-        # start the cycle over for each new cycle call.
-        # Liquid-C does not have a cache, so we don't need to dup the object.
         var = parse_expression(Regexp.last_match(1))
-        var.is_a?(VariableLookup) ? var.dup : var
+        maybe_dup_lookup(var)
       end.compact
     end
 
+    # For backwards compatibility, whenever a lookup is used in an unnamed cycle,
+    # we make it so that the @variables.to_s produces different strings for cycles
+    # called with the same arguments (since @variables.to_s is used as the cycle counter key)
+    # This makes it so {% cycle a, b %} and {% cycle a, b %} have independent counters even if a and b share value.
+    # This is not true for literal values, {% cycle "a", "b" %} and {% cycle "a", "b" %} share the same counter.
+    # I was really scratching my head about this one, but migrating away from this would be more headache
+    # than it's worth. So we're keeping this quirk for now.
+    def maybe_dup_lookup(var)
+      var.is_a?(VariableLookup) ? var.dup : var
+    end
+
     class ParseTreeVisitor < Liquid::ParseTreeVisitor
       def children
         Array(@node.variables)

lib/liquid/tags/decrement.rb

@@ -7,6 +7,10 @@ module Liquid
   # @liquid_name decrement
   # @liquid_summary
   #   Creates a new variable, with a default value of -1, that's decreased by 1 with each subsequent call.
+  #
+  #   > Caution:
+  #   > Predefined Liquid objects can be overridden by variables with the same name.
+  #   > To make sure that you can access all Liquid objects, make sure that your variable name doesn't match a predefined object's name.
   # @liquid_description
   #   Variables that are declared with `decrement` are unique to the [layout](/themes/architecture/layouts), [template](/themes/architecture/templates),
   #   or [section](/themes/architecture/sections) file that they're created in. However, the variable is shared across

lib/liquid/tags/doc.rb

@@ -36,6 +36,8 @@ module Liquid
     end
 
     def parse(tokens)
+      @body = +""
+
       while (token = tokens.shift)
         tag_name = token =~ BlockBody::FullTokenPossiblyInvalid && Regexp.last_match(2)
 
@@ -43,8 +45,10 @@ module Liquid
 
         if tag_name == block_delimiter
           parse_context.trim_whitespace = (token[-3] == WhitespaceControl)
+          @body << Regexp.last_match(1) if Regexp.last_match(1) != ""
           return
         end
+        @body << token unless token.empty?
       end
 
       raise_tag_never_closed(block_name)
@@ -55,11 +59,11 @@ module Liquid
     end
 
     def blank?
-      true
+      @body.empty?
     end
 
     def nodelist
-      []
+      [@body]
     end
 
     private

lib/liquid/tags/for.rb

@@ -20,8 +20,8 @@ module Liquid
   # @liquid_syntax_keyword variable The current item in the array.
   # @liquid_syntax_keyword array The array to iterate over.
   # @liquid_syntax_keyword expression The expression to render for each iteration.
-  # @liquid_optional_param limit [number] The number of iterations to perform.
-  # @liquid_optional_param offset [number] The 1-based index to start iterating at.
+  # @liquid_optional_param limit: [number] The number of iterations to perform.
+  # @liquid_optional_param offset: [number] The 1-based index to start iterating at.
   # @liquid_optional_param range [untyped] A custom numeric range to iterate over.
   # @liquid_optional_param reversed [untyped] Iterate in reverse order.
   class For < Block
@@ -93,7 +93,7 @@ module Liquid
       raise SyntaxError, options[:locale].t("errors.syntax.for_invalid_in") unless p.id?('in')
 
       collection_name  = p.expression
-      @collection_name = parse_expression(collection_name)
+      @collection_name = parse_expression(collection_name, safe: true)
 
       @name     = "#{@variable_name}-#{collection_name}"
       @reversed = p.id?('reversed')
@@ -104,13 +104,17 @@ module Liquid
           raise SyntaxError, options[:locale].t("errors.syntax.for_invalid_attribute")
         end
         p.consume(:colon)
-        set_attribute(attribute, p.expression)
+        set_attribute(attribute, p.expression, safe: true)
       end
       p.consume(:end_of_string)
     end
 
     private
 
+    def strict2_parse(markup)
+      strict_parse(markup)
+    end
+
     def collection_segment(context)
       offsets = context.registers[:for] ||= {}
 
@@ -174,16 +178,16 @@ module Liquid
       output
     end
 
-    def set_attribute(key, expr)
+    def set_attribute(key, expr, safe: false)
       case key
       when 'offset'
         @from = if expr == 'continue'
           :continue
         else
-          parse_expression(expr)
+          parse_expression(expr, safe: safe)
         end
       when 'limit'
-        @limit = parse_expression(expr)
+        @limit = parse_expression(expr, safe: safe)
       end
     end
 

lib/liquid/tags/if.rb

@@ -66,6 +66,10 @@ module Liquid
 
     private
 
+    def strict2_parse(markup)
+      strict_parse(markup)
+    end
+
     def push_block(tag, markup)
       block = if tag == 'else'
         ElseCondition.new
@@ -77,8 +81,8 @@ module Liquid
       block.attach(new_body)
     end
 
-    def parse_expression(markup)
-      Condition.parse_expression(parse_context, markup)
+    def parse_expression(markup, safe: false)
+      Condition.parse_expression(parse_context, markup, safe: safe)
     end
 
     def lax_parse(markup)
@@ -120,9 +124,9 @@ module Liquid
     end
 
     def parse_comparison(p)
-      a = parse_expression(p.expression)
+      a = parse_expression(p.expression, safe: true)
       if (op = p.consume?(:comparison))
-        b = parse_expression(p.expression)
+        b = parse_expression(p.expression, safe: true)
         Condition.new(a, op, b)
       else
         Condition.new(a)

lib/liquid/tags/include.rb

@@ -27,24 +27,7 @@ module Liquid
 
     def initialize(tag_name, markup, options)
       super
-
-      if markup =~ SYNTAX
-
-        template_name = Regexp.last_match(1)
-        variable_name = Regexp.last_match(3)
-
-        @alias_name         = Regexp.last_match(5)
-        @variable_name_expr = variable_name ? parse_expression(variable_name) : nil
-        @template_name_expr = parse_expression(template_name)
-        @attributes         = {}
-
-        markup.scan(TagAttributes) do |key, value|
-          @attributes[key] = parse_expression(value)
-        end
-
-      else
-        raise SyntaxError, options[:locale].t("errors.syntax.include")
-      end
+      parse_with_selected_parser(markup)
     end
 
     def parse(_tokens)
@@ -101,6 +84,49 @@ module Liquid
     alias_method :parse_context, :options
     private :parse_context
 
+    def strict2_parse(markup)
+      p = @parse_context.new_parser(markup)
+
+      @template_name_expr = safe_parse_expression(p)
+      @variable_name_expr = safe_parse_expression(p) if p.id?("for") || p.id?("with")
+      @alias_name         = p.consume(:id) if p.id?("as")
+
+      p.consume?(:comma)
+
+      @attributes = {}
+      while p.look(:id)
+        key = p.consume
+        p.consume(:colon)
+        @attributes[key] = safe_parse_expression(p)
+        p.consume?(:comma)
+      end
+
+      p.consume(:end_of_string)
+    end
+
+    def strict_parse(markup)
+      lax_parse(markup)
+    end
+
+    def lax_parse(markup)
+      if markup =~ SYNTAX
+        template_name = Regexp.last_match(1)
+        variable_name = Regexp.last_match(3)
+
+        @alias_name         = Regexp.last_match(5)
+        @variable_name_expr = variable_name ? parse_expression(variable_name) : nil
+        @template_name_expr = parse_expression(template_name)
+        @attributes         = {}
+
+        markup.scan(TagAttributes) do |key, value|
+          @attributes[key] = parse_expression(value)
+        end
+
+      else
+        raise SyntaxError, options[:locale].t("errors.syntax.include")
+      end
+    end
+
     class ParseTreeVisitor < Liquid::ParseTreeVisitor
       def children
         [

lib/liquid/tags/increment.rb

@@ -7,6 +7,10 @@ module Liquid
   # @liquid_name increment
   # @liquid_summary
   #   Creates a new variable, with a default value of 0, that's increased by 1 with each subsequent call.
+  #
+  #   > Caution:
+  #   > Predefined Liquid objects can be overridden by variables with the same name.
+  #   > To make sure that you can access all Liquid objects, make sure that your variable name doesn't match a predefined object's name.
   # @liquid_description
   #   Variables that are declared with `increment` are unique to the [layout](/themes/architecture/layouts), [template](/themes/architecture/templates),
   #   or [section](/themes/architecture/sections) file that they're created in. However, the variable is shared across

lib/liquid/tags/render.rb

@@ -35,22 +35,7 @@ module Liquid
 
     def initialize(tag_name, markup, options)
       super
-
-      raise SyntaxError, options[:locale].t("errors.syntax.render") unless markup =~ SYNTAX
-
-      template_name = Regexp.last_match(1)
-      with_or_for = Regexp.last_match(3)
-      variable_name = Regexp.last_match(4)
-
-      @alias_name = Regexp.last_match(6)
-      @variable_name_expr = variable_name ? parse_expression(variable_name) : nil
-      @template_name_expr = parse_expression(template_name)
-      @is_for_loop = (with_or_for == FOR)
-
-      @attributes = {}
-      markup.scan(TagAttributes) do |key, value|
-        @attributes[key] = parse_expression(value)
-      end
+      parse_with_selected_parser(markup)
     end
 
     def for_loop?
@@ -99,6 +84,55 @@ module Liquid
       output
     end
 
+    # render (string) (with|for expression)? (as id)? (key: value)*
+    def strict2_parse(markup)
+      p = @parse_context.new_parser(markup)
+
+      @template_name_expr = parse_expression(strict2_template_name(p), safe: true)
+      with_or_for         = p.id?("for") || p.id?("with")
+      @variable_name_expr = safe_parse_expression(p) if with_or_for
+      @alias_name         = p.consume(:id) if p.id?("as")
+      @is_for_loop        = (with_or_for == FOR)
+
+      p.consume?(:comma)
+
+      @attributes = {}
+      while p.look(:id)
+        key = p.consume
+        p.consume(:colon)
+        @attributes[key] = safe_parse_expression(p)
+        p.consume?(:comma)
+      end
+
+      p.consume(:end_of_string)
+    end
+
+    def strict2_template_name(p)
+      p.consume(:string)
+    end
+
+    def strict_parse(markup)
+      lax_parse(markup)
+    end
+
+    def lax_parse(markup)
+      raise SyntaxError, options[:locale].t("errors.syntax.render") unless markup =~ SYNTAX
+
+      template_name = Regexp.last_match(1)
+      with_or_for = Regexp.last_match(3)
+      variable_name = Regexp.last_match(4)
+
+      @alias_name = Regexp.last_match(6)
+      @variable_name_expr = variable_name ? parse_expression(variable_name) : nil
+      @template_name_expr = parse_expression(template_name)
+      @is_for_loop = (with_or_for == FOR)
+
+      @attributes = {}
+      markup.scan(TagAttributes) do |key, value|
+        @attributes[key] = parse_expression(value)
+      end
+    end
+
     class ParseTreeVisitor < Liquid::ParseTreeVisitor
       def children
         [

lib/liquid/tags/table_row.rb

@@ -19,17 +19,54 @@ module Liquid
   # @liquid_syntax_keyword variable The current item in the array.
   # @liquid_syntax_keyword array The array to iterate over.
   # @liquid_syntax_keyword expression The expression to render.
-  # @liquid_optional_param cols [number] The number of columns that the table should have.
-  # @liquid_optional_param limit [number] The number of iterations to perform.
-  # @liquid_optional_param offset [number] The 1-based index to start iterating at.
+  # @liquid_optional_param cols: [number] The number of columns that the table should have.
+  # @liquid_optional_param limit: [number] The number of iterations to perform.
+  # @liquid_optional_param offset: [number] The 1-based index to start iterating at.
   # @liquid_optional_param range [untyped] A custom numeric range to iterate over.
   class TableRow < Block
     Syntax = /(\w+)\s+in\s+(#{QuotedFragment}+)/o
+    ALLOWED_ATTRIBUTES = ['cols', 'limit', 'offset', 'range'].freeze
 
     attr_reader :variable_name, :collection_name, :attributes
 
     def initialize(tag_name, markup, options)
       super
+      parse_with_selected_parser(markup)
+    end
+
+    def strict2_parse(markup)
+      p = @parse_context.new_parser(markup)
+
+      @variable_name = p.consume(:id)
+
+      unless p.id?("in")
+        raise SyntaxError, options[:locale].t("errors.syntax.for_invalid_in")
+      end
+
+      @collection_name = safe_parse_expression(p)
+
+      p.consume?(:comma)
+
+      @attributes = {}
+      while p.look(:id)
+        key = p.consume
+        unless ALLOWED_ATTRIBUTES.include?(key)
+          raise SyntaxError, options[:locale].t("errors.syntax.table_row_invalid_attribute", attribute: key)
+        end
+
+        p.consume(:colon)
+        @attributes[key] = safe_parse_expression(p)
+        p.consume?(:comma)
+      end
+
+      p.consume(:end_of_string)
+    end
+
+    def strict_parse(markup)
+      lax_parse(markup)
+    end
+
+    def lax_parse(markup)
       if markup =~ Syntax
         @variable_name   = Regexp.last_match(1)
         @collection_name = parse_expression(Regexp.last_match(2))

lib/liquid/template.rb

@@ -2,7 +2,7 @@
 
 module Liquid
   # Templates are central to liquid.
-  # Interpretating templates is a two step process. First you compile the
+  # Interpreting templates is a two step process. First you compile the
   # source code you got. During compile time some extensive error checking is performed.
   # your code should expect to get some SyntaxErrors.
   #
@@ -24,7 +24,8 @@ module Liquid
       # Sets how strict the parser should be.
       # :lax acts like liquid 2.5 and silently ignores malformed tags in most cases.
       # :warn is the default and will give deprecation warnings when invalid syntax is used.
-      # :strict will enforce correct syntax.
+      # :strict enforces correct syntax for most tags
+      # :strict2 enforces correct syntax for all tags
       def error_mode=(mode)
         Deprecations.warn("Template.error_mode=", "Environment#error_mode=")
         Environment.default.error_mode = mode

lib/liquid/tokenizer.rb

@@ -117,7 +117,7 @@ module Liquid
       byte_a = byte_b = @ss.scan_byte
 
       while byte_b
-        byte_a = @ss.scan_byte while byte_a && (byte_a != CLOSE_CURLEY && byte_a != OPEN_CURLEY)
+        byte_a = @ss.scan_byte while byte_a && byte_a != CLOSE_CURLEY && byte_a != OPEN_CURLEY
 
         break unless byte_a
 

lib/liquid/utils.rb

@@ -2,6 +2,9 @@
 
 module Liquid
   module Utils
+    DECIMAL_REGEX = /\A-?\d+\.\d+\z/
+    UNIX_TIMESTAMP_REGEX = /\A\d+\z/
+
     def self.slice_collection(collection, from, to)
       if (from != 0 || !to.nil?) && collection.respond_to?(:load_slice)
         collection.load_slice(from, to)
@@ -52,7 +55,7 @@ module Liquid
       when Numeric
         obj
       when String
-        /\A-?\d+\.\d+\z/.match?(obj.strip) ? BigDecimal(obj) : obj.to_i
+        DECIMAL_REGEX.match?(obj.strip) ? BigDecimal(obj) : obj.to_i
       else
         if obj.respond_to?(:to_number)
           obj.to_number
@@ -66,14 +69,14 @@ module Liquid
       return obj if obj.respond_to?(:strftime)
 
       if obj.is_a?(String)
-        return nil if obj.empty?
+        return if obj.empty?
         obj = obj.downcase
       end
 
       case obj
       when 'now', 'today'
         Time.now
-      when /\A\d+\z/, Integer
+      when UNIX_TIMESTAMP_REGEX, Integer
         Time.at(obj.to_i)
       when String
         Time.parse(obj)
@@ -92,6 +95,8 @@ module Liquid
 
     def self.to_s(obj, seen = {})
       case obj
+      when BigDecimal
+        obj.to_s("F")
       when Hash
         # If the custom hash implementation overrides `#to_s`, use their
         # custom implementation. Otherwise we use Liquid's default

lib/liquid/variable.rb

@@ -54,7 +54,7 @@ module Liquid
           next unless f =~ /\w+/
           filtername = Regexp.last_match(0)
           filterargs = f.scan(FilterArgsRegex).flatten
-          @filters << parse_filter_expressions(filtername, filterargs)
+          @filters << lax_parse_filter_expressions(filtername, filterargs)
         end
       end
     end
@@ -65,15 +65,26 @@ module Liquid
 
       return if p.look(:end_of_string)
 
-      @name = parse_context.parse_expression(p.expression)
+      @name = parse_context.safe_parse_expression(p)
       while p.consume?(:pipe)
         filtername = p.consume(:id)
         filterargs = p.consume?(:colon) ? parse_filterargs(p) : Const::EMPTY_ARRAY
-        @filters << parse_filter_expressions(filtername, filterargs)
+        @filters << lax_parse_filter_expressions(filtername, filterargs)
       end
       p.consume(:end_of_string)
     end
 
+    def strict2_parse(markup)
+      @filters = []
+      p = @parse_context.new_parser(markup)
+
+      return if p.look(:end_of_string)
+
+      @name = parse_context.safe_parse_expression(p)
+      @filters << strict2_parse_filter_expressions(p) while p.consume?(:pipe)
+      p.consume(:end_of_string)
+    end
+
     def parse_filterargs(p)
       # first argument
       filterargs = [p.argument]
@@ -122,7 +133,7 @@ module Liquid
 
     private
 
-    def parse_filter_expressions(filter_name, unparsed_args)
+    def lax_parse_filter_expressions(filter_name, unparsed_args)
       filter_args  = []
       keyword_args = nil
       unparsed_args.each do |a|
@@ -138,6 +149,46 @@ module Liquid
       result
     end
 
+    # Surprisingly, positional and keyword arguments can be mixed.
+    #
+    # filter = filtername [":" filterargs?]
+    # filterargs = argument ("," argument)*
+    # argument = (positional_argument | keyword_argument)
+    # positional_argument = expression
+    # keyword_argument = id ":" expression
+    def strict2_parse_filter_expressions(p)
+      filtername = p.consume(:id)
+      filter_args = []
+      keyword_args = {}
+
+      if p.consume?(:colon)
+        # Parse first argument (no leading comma)
+        argument(p, filter_args, keyword_args) unless end_of_arguments?(p)
+
+        # Parse remaining arguments (with leading commas) and optional trailing comma
+        argument(p, filter_args, keyword_args) while p.consume?(:comma) && !end_of_arguments?(p)
+      end
+
+      result = [filtername, filter_args]
+      result << keyword_args unless keyword_args.empty?
+      result
+    end
+
+    def argument(p, positional_arguments, keyword_arguments)
+      if p.look(:id) && p.look(:colon, 1)
+        key = p.consume(:id)
+        p.consume(:colon)
+        value = parse_context.safe_parse_expression(p)
+        keyword_arguments[key] = value
+      else
+        positional_arguments << parse_context.safe_parse_expression(p)
+      end
+    end
+
+    def end_of_arguments?(p)
+      p.look(:pipe) || p.look(:end_of_string)
+    end
+
     def evaluate_filter_expressions(context, filter_args, filter_kwargs)
       parsed_args = filter_args.map { |expr| context.evaluate(expr) }
       if filter_kwargs

lib/liquid/variable_lookup.rb

@@ -4,6 +4,25 @@ module Liquid
   class VariableLookup
     COMMAND_METHODS = ['size', 'first', 'last'].freeze
 
+    # Matches simple identifier chains: name(.name)* with no brackets/quotes
+    SIMPLE_LOOKUP_RE = /\A[\w-]+\??(?:\.[\w-]+\??)*\z/
+
+    # Returns true when markup is a simple dotted identifier chain that the
+    # fast path in initialize can handle. Accepts:
+    #   - Single names: "product", "item"
+    #   - Dotted chains: "product.title", "cart.items.first"
+    #   - Question-mark suffixes: "product.available?"
+    #   - Hyphens in names: "my-var.some-field"
+    # Rejects (falls through to VariableParser regex):
+    #   - Bracket lookups: "product[0]", "hash['key']"
+    #   - Quoted strings, empty input, leading/trailing dots
+    # Fallback: when this returns false, initialize uses the original
+    #   markup.scan(VariableParser) path — behavior is identical to
+    #   the pre-optimization code for any input the fast path rejects.
+    def self.simple_lookup?(markup)
+      markup.bytesize > 0 && markup.match?(SIMPLE_LOOKUP_RE)
+    end
+
     attr_reader :name, :lookups
 
     def self.parse(markup, string_scanner = StringScanner.new(""), cache = nil)
@@ -11,6 +30,31 @@ module Liquid
     end
 
     def initialize(markup, string_scanner = StringScanner.new(""), cache = nil)
+      if self.class.simple_lookup?(markup)
+        dot_pos = markup.index('.')
+        if dot_pos.nil?
+          @name = markup
+          @lookups = Const::EMPTY_ARRAY
+          @command_flags = 0
+          return
+        end
+
+        @name = markup.byteslice(0, dot_pos)
+        @lookups = []
+        @command_flags = 0
+        pos = dot_pos + 1
+        len = markup.bytesize
+        while pos < len
+          seg_start = pos
+          pos += 1 while pos < len && markup.getbyte(pos) != ByteTables::DOT
+          seg = markup.byteslice(seg_start, pos - seg_start)
+          @command_flags |= 1 << @lookups.length if COMMAND_METHODS.include?(seg)
+          @lookups << seg
+          pos += 1 # skip dot
+        end
+        return
+      end
+
       lookups = markup.scan(VariableParser)
 
       name = lookups.shift
@@ -70,6 +114,11 @@ module Liquid
         elsif lookup_command?(i) && object.respond_to?(key)
           object = object.send(key).to_liquid
 
+        # Handle string first/last like ActiveSupport does (returns first/last character)
+        # ActiveSupport returns "" for empty strings, not nil
+        elsif lookup_command?(i) && object.is_a?(String) && (key == "first" || key == "last")
+          object = key == "first" ? (object[0] || "") : (object[-1] || "")
+
           # No key was present with the desired value and it wasn't one of the directly supported
           # keywords either. The only thing we got left is to return nil or
           # raise an exception if `strict_variables` option is set to true

lib/liquid/version.rb

@@ -2,5 +2,5 @@
 # frozen_string_literal: true
 
 module Liquid
-  VERSION = "5.8.6"
+  VERSION = "5.12.0"
 end

performance/bench_quick.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+# Quick benchmark: measures parse µs, render µs, and object allocations
+# Outputs machine-readable metrics to stdout
+
+require_relative 'theme_runner'
+
+RubyVM::YJIT.enable if defined?(RubyVM::YJIT)
+
+runner = ThemeRunner.new
+
+# Warmup — enough iterations for YJIT to fully optimize hot paths
+20.times { runner.compile }
+20.times { runner.render }
+
+GC.start
+GC.compact if GC.respond_to?(:compact)
+
+# Measure parse
+parse_times = []
+10.times do
+  GC.disable
+  t0 = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+  runner.compile
+  t1 = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+  GC.enable
+  GC.start
+  parse_times << (t1 - t0) * 1_000_000 # µs
+end
+
+# Measure render
+render_times = []
+10.times do
+  GC.disable
+  t0 = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+  runner.render
+  t1 = Process.clock_gettime(Process::CLOCK_MONOTONIC)
+  GC.enable
+  GC.start
+  render_times << (t1 - t0) * 1_000_000 # µs
+end
+
+# Measure object allocations for one parse+render cycle
+require 'objspace'
+GC.start
+GC.disable
+before = ObjectSpace.count_objects.values_at(:TOTAL).first - ObjectSpace.count_objects.values_at(:FREE).first
+runner.compile
+runner.render
+after = ObjectSpace.count_objects.values_at(:TOTAL).first - ObjectSpace.count_objects.values_at(:FREE).first
+GC.enable
+allocations = after - before
+
+parse_us = parse_times.min.round(0)
+render_us = render_times.min.round(0)
+combined_us = parse_us + render_us
+
+puts "RESULTS"
+puts "parse_us=#{parse_us}"
+puts "render_us=#{render_us}"
+puts "combined_us=#{combined_us}"
+puts "allocations=#{allocations}"

spec/ruby_liquid.rb

@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# Liquid Spec Adapter for Shopify/liquid (Ruby reference implementation)
+#
+# Run with: bundle exec liquid-spec run spec/ruby_liquid.rb
+
+$LOAD_PATH.unshift(File.expand_path('../lib', __dir__))
+require 'liquid'
+
+LiquidSpec.configure do |config|
+  # Run core Liquid specs
+  config.features = [:core]
+end
+
+# Compile a template string into a Liquid::Template
+LiquidSpec.compile do |ctx, source, options|
+  ctx[:template] = Liquid::Template.parse(source, **options)
+end
+
+# Render a compiled template with the given context
+# @param ctx [Hash] adapter context containing :template
+# @param assigns [Hash] environment variables
+# @param options [Hash] :registers, :strict_errors, :exception_renderer
+LiquidSpec.render do |ctx, assigns, options|
+  registers = Liquid::Registers.new(options[:registers] || {})
+
+  context = Liquid::Context.build(
+    static_environments: assigns,
+    registers: registers,
+    rethrow_errors: options[:strict_errors],
+  )
+
+  context.exception_renderer = options[:exception_renderer] if options[:exception_renderer]
+
+  ctx[:template].render(context)
+end

spec/ruby_liquid_lax.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+# Liquid Spec Adapter for Shopify/liquid with lax parsing mode
+#
+# Run with: bundle exec liquid-spec run spec/ruby_liquid_lax.rb
+
+$LOAD_PATH.unshift(File.expand_path('../lib', __dir__))
+require 'liquid'
+
+LiquidSpec.configure do |config|
+  config.features = [:core, :lax_parsing]
+end
+
+# Compile a template string into a Liquid::Template
+LiquidSpec.compile do |ctx, source, options|
+  # Force lax mode
+  options = options.merge(error_mode: :lax)
+  ctx[:template] = Liquid::Template.parse(source, **options)
+end
+
+# Render a compiled template with the given context
+LiquidSpec.render do |ctx, assigns, options|
+  registers = Liquid::Registers.new(options[:registers] || {})
+
+  context = Liquid::Context.build(
+    static_environments: assigns,
+    registers: registers,
+    rethrow_errors: options[:strict_errors],
+  )
+
+  context.exception_renderer = options[:exception_renderer] if options[:exception_renderer]
+
+  ctx[:template].render(context)
+end

spec/ruby_liquid_with_active_support.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+# Liquid Spec Adapter for Shopify/liquid with ActiveSupport loaded
+#
+# Run with: bundle exec liquid-spec run spec/ruby_liquid_with_active_support.rb
+
+$LOAD_PATH.unshift(File.expand_path('../lib', __dir__))
+require 'active_support/all'
+require 'liquid'
+
+LiquidSpec.configure do |config|
+  # Run core Liquid specs plus ActiveSupport SafeBuffer tests
+  config.features = [:core, :activesupport]
+end
+
+# Compile a template string into a Liquid::Template
+LiquidSpec.compile do |ctx, source, options|
+  ctx[:template] = Liquid::Template.parse(source, **options)
+end
+
+# Render a compiled template with the given context
+# @param ctx [Hash] adapter context containing :template
+# @param assigns [Hash] environment variables
+# @param options [Hash] :registers, :strict_errors, :exception_renderer
+LiquidSpec.render do |ctx, assigns, options|
+  registers = Liquid::Registers.new(options[:registers] || {})
+
+  context = Liquid::Context.build(
+    static_environments: assigns,
+    registers: registers,
+    rethrow_errors: options[:strict_errors],
+  )
+
+  context.exception_renderer = options[:exception_renderer] if options[:exception_renderer]
+
+  ctx[:template].render(context)
+end

spec/ruby_liquid_yjit.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+# Liquid Spec Adapter for Shopify/liquid with YJIT + strict mode + ActiveSupport
+#
+# Run with: bundle exec liquid-spec run spec/ruby_liquid_yjit.rb
+
+$LOAD_PATH.unshift(File.expand_path('../lib', __dir__))
+
+# Enable YJIT if available
+if defined?(RubyVM::YJIT) && RubyVM::YJIT.respond_to?(:enable)
+  RubyVM::YJIT.enable
+end
+
+require 'active_support/all'
+require 'liquid'
+
+LiquidSpec.configure do |config|
+  config.features = [:core, :activesupport]
+end
+
+# Compile a template string into a Liquid::Template
+LiquidSpec.compile do |ctx, source, options|
+  # Force strict mode
+  options = { error_mode: :strict }.merge(options)
+  ctx[:template] = Liquid::Template.parse(source, **options)
+end
+
+# Render a compiled template with the given context
+LiquidSpec.render do |ctx, assigns, options|
+  registers = Liquid::Registers.new(options[:registers] || {})
+
+  context = Liquid::Context.build(
+    static_environments: assigns,
+    registers: registers,
+    rethrow_errors: options[:strict_errors],
+  )
+
+  context.exception_renderer = options[:exception_renderer] if options[:exception_renderer]
+
+  ctx[:template].render(context)
+end

test/integration/context_test.rb

@@ -632,13 +632,28 @@ class ContextTest < Minitest::Test
   end
 
   def test_has_key_will_not_add_an_error_for_missing_keys
-    with_error_mode(:strict) do
+    with_error_modes(:strict) do
       context = Context.new
       context.key?('unknown')
       assert_empty(context.errors)
     end
   end
 
+  def test_key_lookup_will_raise_for_missing_keys_when_strict_variables_is_enabled
+    context = Context.new
+    context.strict_variables = true
+    assert_raises(Liquid::UndefinedVariable) do
+      context['unknown']
+    end
+  end
+
+  def test_has_key_will_not_raise_for_missing_keys_when_strict_variables_is_enabled
+    context = Context.new
+    context.strict_variables = true
+    refute(context.key?('unknown'))
+    assert_empty(context.errors)
+  end
+
   def test_context_always_uses_static_registers
     registers = {
       my_register: :my_value,

test/integration/error_handling_test.rb

@@ -67,7 +67,7 @@ class ErrorHandlingTest < Minitest::Test
   end
 
   def test_unrecognized_operator
-    with_error_mode(:strict) do
+    with_error_modes(:strict) do
       assert_raises(SyntaxError) do
         Liquid::Template.parse(' {% if 1 =! 2 %}ok{% endif %} ')
       end

test/integration/expression_test.rb

@@ -26,8 +26,12 @@ class ExpressionTest < Minitest::Test
   def test_float
     assert_template_result("-17.42", "{{ -17.42 }}")
     assert_template_result("2.5", "{{ 2.5 }}")
-    assert_expression_result(0.0, "0.....5")
-    assert_expression_result(0.0, "-0..1")
+
+    with_error_modes(:lax) do
+      assert_expression_result(0.0, "0.....5")
+      assert_expression_result(0.0, "-0..1")
+    end
+
     assert_expression_result(1.5, "1.5")
 
     # this is a unfortunate quirky behavior of Liquid
@@ -61,6 +65,7 @@ class ExpressionTest < Minitest::Test
     assert_template_result(
       "",
       "{{ - 'theme.css' - }}",
+      error_mode: :lax,
     )
   end
 
@@ -147,6 +152,35 @@ class ExpressionTest < Minitest::Test
     assert(parse_context.instance_variable_get(:@expression_cache).nil?)
   end
 
+  def test_safe_parse_with_variable_lookup
+    parse_context = Liquid::ParseContext.new
+    parser = parse_context.new_parser('product.title')
+    result = Liquid::Expression.safe_parse(parser)
+
+    assert_instance_of(Liquid::VariableLookup, result)
+    assert_equal('product', result.name)
+    assert_equal(['title'], result.lookups)
+  end
+
+  def test_safe_parse_with_number
+    parse_context = Liquid::ParseContext.new
+    parser = parse_context.new_parser('42')
+    result = Liquid::Expression.safe_parse(parser)
+
+    assert_equal(42, result)
+  end
+
+  def test_safe_parse_raises_syntax_error_for_invalid_expression
+    parse_context = Liquid::ParseContext.new
+    parser = parse_context.new_parser('')
+
+    error = assert_raises(Liquid::SyntaxError) do
+      Liquid::Expression.safe_parse(parser)
+    end
+
+    assert_match(/is not a valid expression/, error.message)
+  end
+
   private
 
   def assert_expression_result(expect, markup, **assigns)

test/integration/hash_rendering_test.rb

@@ -88,17 +88,11 @@ class HashRenderingTest < Minitest::Test
   end
 
   def test_rendering_hash_with_custom_to_s_method_uses_custom_to_s
-    my_hash = Class.new(Hash) do
-      def to_s
-        "kewl"
-      end
-    end.new
-
-    assert_template_result("kewl", "{{ my_hash }}", { "my_hash" => my_hash })
+    assert_template_result("kewl", "{{ my_hash }}", { "my_hash" => HashWithCustomToS.new })
   end
 
   def test_rendering_hash_without_custom_to_s_uses_default_inspect
-    my_hash = Class.new(Hash).new
+    my_hash = HashWithoutCustomToS.new
     my_hash[:foo] = :bar
 
     assert_template_result("{:foo=>:bar}", "{{ my_hash }}", { "my_hash" => my_hash })

test/integration/parsing_quirks_test.rb

@@ -31,18 +31,18 @@ class ParsingQuirksTest < Minitest::Test
   def test_error_on_empty_filter
     assert(Template.parse("{{test}}"))
 
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       assert(Template.parse("{{|test}}"))
     end
 
-    with_error_mode(:strict) do
+    with_error_modes(:strict) do
       assert_raises(SyntaxError) { Template.parse("{{|test}}") }
       assert_raises(SyntaxError) { Template.parse("{{test |a|b|}}") }
     end
   end
 
   def test_meaningless_parens_error
-    with_error_mode(:strict) do
+    with_error_modes(:strict) do
       assert_raises(SyntaxError) do
         markup = "a == 'foo' or (b == 'bar' and c == 'baz') or false"
         Template.parse("{% if #{markup} %} YES {% endif %}")
@@ -51,7 +51,7 @@ class ParsingQuirksTest < Minitest::Test
   end
 
   def test_unexpected_characters_syntax_error
-    with_error_mode(:strict) do
+    with_error_modes(:strict) do
       assert_raises(SyntaxError) do
         markup = "true && false"
         Template.parse("{% if #{markup} %} YES {% endif %}")
@@ -70,7 +70,7 @@ class ParsingQuirksTest < Minitest::Test
   end
 
   def test_meaningless_parens_lax
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       assigns = { 'b' => 'bar', 'c' => 'baz' }
       markup  = "a == 'foo' or (b == 'bar' and c == 'baz') or false"
       assert_template_result(' YES ', "{% if #{markup} %} YES {% endif %}", assigns)
@@ -78,7 +78,7 @@ class ParsingQuirksTest < Minitest::Test
   end
 
   def test_unexpected_characters_silently_eat_logic_lax
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       markup = "true && false"
       assert_template_result(' YES ', "{% if #{markup} %} YES {% endif %}")
       markup = "false || true"
@@ -93,7 +93,7 @@ class ParsingQuirksTest < Minitest::Test
   end
 
   def test_unanchored_filter_arguments
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       assert_template_result('hi', "{{ 'hi there' | split$$$:' ' | first }}")
 
       assert_template_result('x', "{{ 'X' | downcase) }}")
@@ -106,14 +106,14 @@ class ParsingQuirksTest < Minitest::Test
   end
 
   def test_invalid_variables_work
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       assert_template_result('bar', "{% assign 123foo = 'bar' %}{{ 123foo }}")
       assert_template_result('123', "{% assign 123 = 'bar' %}{{ 123 }}")
     end
   end
 
   def test_extra_dots_in_ranges
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       assert_template_result('12345', "{% for i in (1...5) %}{{ i }}{% endfor %}")
     end
   end
@@ -133,7 +133,7 @@ class ParsingQuirksTest < Minitest::Test
   end
 
   def test_incomplete_expression
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       assert_template_result("false", "{{ false - }}")
       assert_template_result("false", "{{ false > }}")
       assert_template_result("false", "{{ false < }}")

test/integration/security_test.rb

@@ -44,33 +44,40 @@ class SecurityTest < Minitest::Test
   end
 
   def test_does_not_permanently_add_filters_to_symbol_table
-    current_symbols = Symbol.all_symbols
+    assert_no_new_symbols do
+      # MRI imprecisely marks objects found on the C stack, which can result
+      # in uninitialized memory being marked. This can even result in the test failing
+      # deterministically for a given compilation of ruby. Using a separate thread will
+      # keep these writes of the symbol pointer on a separate stack that will be garbage
+      # collected after Thread#join.
+      Thread.new do
+        test = %( {{ "some_string" | a_bad_filter }} )
+        Template.parse(test).render!
+        nil
+      end.join
 
-    # MRI imprecisely marks objects found on the C stack, which can result
-    # in uninitialized memory being marked. This can even result in the test failing
-    # deterministically for a given compilation of ruby. Using a separate thread will
-    # keep these writes of the symbol pointer on a separate stack that will be garbage
-    # collected after Thread#join.
-    Thread.new do
-      test = %( {{ "some_string" | a_bad_filter }} )
-      Template.parse(test).render!
-      nil
-    end.join
-
-    GC.start
-
-    assert_equal([], (Symbol.all_symbols - current_symbols))
+      GC.start
+    end
   end
 
   def test_does_not_add_drop_methods_to_symbol_table
+    assert_no_new_symbols do
+      assigns = { 'drop' => Drop.new }
+      assert_equal("", Template.parse("{{ drop.custom_method_1 }}", assigns).render!)
+      assert_equal("", Template.parse("{{ drop.custom_method_2 }}", assigns).render!)
+      assert_equal("", Template.parse("{{ drop.custom_method_3 }}", assigns).render!)
+    end
+  end
+
+  def assert_no_new_symbols
+    # Run once to trigger any first-time initialization which might create some symbols,
+    # for example autoload or lazy method parsing might create symbols on first execution.
+    yield
+
+    # Ensure no new symbols for further runs, i.e. the code does not leak symbols
     current_symbols = Symbol.all_symbols
-
-    assigns = { 'drop' => Drop.new }
-    assert_equal("", Template.parse("{{ drop.custom_method_1 }}", assigns).render!)
-    assert_equal("", Template.parse("{{ drop.custom_method_2 }}", assigns).render!)
-    assert_equal("", Template.parse("{{ drop.custom_method_3 }}", assigns).render!)
-
-    assert_equal([], (Symbol.all_symbols - current_symbols))
+    yield
+    assert_equal([], Symbol.all_symbols - current_symbols)
   end
 
   def test_max_depth_nested_blocks_does_not_raise_exception

test/integration/standard_filter_test.rb

@@ -116,7 +116,7 @@ class StandardFiltersTest < Minitest::Test
   end
 
   def test_slice_on_arrays
-    input = 'foobar'.split(//)
+    input = 'foobar'.split('')
     assert_equal(%w(o o b), @filters.slice(input, 1, 3))
     assert_equal(%w(o o b a r), @filters.slice(input, 1, 1000))
     assert_equal(%w(), @filters.slice(input, 1, 0))
@@ -164,6 +164,13 @@ class StandardFiltersTest < Minitest::Test
     assert_equal(['A', 'Z'], @filters.split('A1Z', 1))
   end
 
+  def test_squish_filter
+    assert_equal("foo bar boo", Liquid::Template.parse(%({{ " foo   bar
+\t   boo   " | squish }})).render)
+    assert_equal("", Liquid::Template.parse('{{ nil | squish }}').render)
+    assert_equal("", Liquid::Template.parse('{{ " " | squish }}').render)
+  end
+
   def test_escape
     assert_equal('&lt;strong&gt;', @filters.escape('<strong>'))
     assert_equal('1', @filters.escape(1))
@@ -294,13 +301,7 @@ class StandardFiltersTest < Minitest::Test
   end
 
   def test_join_calls_to_liquid_on_each_element
-    drop = Class.new(Liquid::Drop) do
-      def to_liquid
-        'i did it'
-      end
-    end
-
-    assert_equal('i did it, i did it', @filters.join([drop.new, drop.new], ", "))
+    assert_equal('i did it, i did it', @filters.join([CustomToLiquidDrop.new('i did it'), CustomToLiquidDrop.new('i did it')], ", "))
   end
 
   def test_sort
@@ -633,6 +634,40 @@ class StandardFiltersTest < Minitest::Test
     assert_nil(@filters.last([]))
   end
 
+  def test_first_last_on_strings
+    # Ruby's String class does not have first/last methods by default.
+    # ActiveSupport adds String#first and String#last to return the first/last character.
+    # Liquid must work without ActiveSupport, so the first/last filters handle strings specially.
+    #
+    # This enables template patterns like:
+    #   {{ product.title | first }}  => "S" (for "Snowboard")
+    #   {{ customer.name | last }}   => "h" (for "Smith")
+    #
+    # Note: ActiveSupport returns "" for empty strings, not nil.
+    assert_equal('f', @filters.first('foo'))
+    assert_equal('o', @filters.last('foo'))
+    assert_equal('', @filters.first(''))
+    assert_equal('', @filters.last(''))
+  end
+
+  def test_first_last_on_unicode_strings
+    # Unicode strings should return the first/last grapheme cluster (character),
+    # not the first/last byte. Ruby's String#[] handles this correctly with index 0/-1.
+    # This ensures international text works properly:
+    #   {{ korean_name | first }} => "고" (not a partial byte sequence)
+    assert_equal('고', @filters.first('고스트빈'))
+    assert_equal('빈', @filters.last('고스트빈'))
+  end
+
+  def test_first_last_on_strings_via_template
+    # Integration test to verify the filter works end-to-end in templates.
+    # Empty strings return empty output (nil renders as empty string).
+    assert_template_result('f', '{{ name | first }}', { 'name' => 'foo' })
+    assert_template_result('o', '{{ name | last }}', { 'name' => 'foo' })
+    assert_template_result('', '{{ name | first }}', { 'name' => '' })
+    assert_template_result('', '{{ name | last }}', { 'name' => '' })
+  end
+
   def test_replace
     assert_equal('b b b b', @filters.replace('a a a a', 'a', 'b'))
     assert_equal('2 2 2 2', @filters.replace('1 1 1 1', 1, 2))
@@ -1146,6 +1181,8 @@ class StandardFiltersTest < Minitest::Test
   end
 
   def test_all_filters_never_raise_non_liquid_exception
+    skip("too slow on non-CRuby due to many exceptions") unless RUBY_ENGINE == 'ruby'
+
     test_drop = TestDrop.new(value: "test")
     test_drop.context = Context.new
     test_enum = TestEnumerable.new
@@ -1302,7 +1339,7 @@ class StandardFiltersTest < Minitest::Test
     assert_equal(1, @filters.sum(input, true))
     assert_equal(0.2, @filters.sum(input, 1.0))
     assert_equal(-0.3, @filters.sum(input, 1))
-    assert_equal(0.4, @filters.sum(input, (1..5)))
+    assert_equal(0.4, @filters.sum(input, 1..5))
     assert_equal(0, @filters.sum(input, nil))
     assert_equal(0, @filters.sum(input, ""))
   end

test/integration/tags/cycle_tag_test.rb

@@ -3,20 +3,10 @@
 require 'test_helper'
 
 class CycleTagTest < Minitest::Test
-  def test_simple_cycle
-    template = <<~LIQUID
-      {%- cycle '1', '2', '3' -%}
-      {%- cycle '1', '2', '3' -%}
-      {%- cycle '1', '2', '3' -%}
-    LIQUID
-
-    assert_template_result("123", template)
-  end
-
   def test_simple_cycle_inside_for_loop
     template = <<~LIQUID
       {%- for i in (1..3) -%}
-        {% cycle '1', '2', '3' %}
+        {%- cycle '1', '2', '3' -%}
       {%- endfor -%}
     LIQUID
 
@@ -36,13 +26,157 @@ class CycleTagTest < Minitest::Test
     assert_template_result("123", template)
   end
 
-  def test_cycle_tag_always_resets_cycle
+  def test_cycle_named_groups_string
     template = <<~LIQUID
-      {%- assign a = "1" -%}
-      {%- cycle a, "2" -%}
-      {%- cycle a, "2" -%}
+      {%- for i in (1..3) -%}
+        {%- cycle 'placeholder1': 1, 2, 3 -%}
+        {%- cycle 'placeholder2': 1, 2, 3 -%}
+      {%- endfor -%}
     LIQUID
 
-    assert_template_result("11", template)
+    assert_template_result("112233", template)
+  end
+
+  def test_cycle_named_groups_vlookup
+    template = <<~LIQUID
+      {%- assign placeholder1 = 'placeholder1' -%}
+      {%- assign placeholder2 = 'placeholder2' -%}
+      {%- for i in (1..3) -%}
+        {%- cycle placeholder1: 1, 2, 3 -%}
+        {%- cycle placeholder2: 1, 2, 3 -%}
+      {%- endfor -%}
+    LIQUID
+
+    assert_template_result("112233", template)
+  end
+
+  def test_unnamed_cycle_have_independent_counters_when_used_with_lookups
+    template = <<~LIQUID
+      {%- assign a = "1" -%}
+      {%- for i in (1..3) -%}
+        {%- cycle a, "2" -%}
+        {%- cycle a, "2" -%}
+      {%- endfor -%}
+    LIQUID
+
+    assert_template_result("112211", template)
+  end
+
+  def test_unnamed_cycle_dependent_counter_when_used_with_literal_values
+    template = <<~LIQUID
+      {%- cycle "1", "2" -%}
+      {%- cycle "1", "2" -%}
+      {%- cycle "1", "2" -%}
+    LIQUID
+
+    assert_template_result("121", template)
+  end
+
+  def test_optional_trailing_comma
+    template = <<~LIQUID
+      {%- cycle "1", "2", -%}
+      {%- cycle "1", "2", -%}
+      {%- cycle "1", "2", -%}
+      {%- cycle "1", -%}
+    LIQUID
+
+    assert_template_result("1211", template)
+  end
+
+  def test_cycle_tag_without_arguments
+    error = assert_raises(Liquid::SyntaxError) do
+      Template.parse("{% cycle %}")
+    end
+
+    assert_match(/Syntax Error in 'cycle' - Valid syntax: cycle \[name :\] var/, error.message)
+  end
+
+  def test_cycle_tag_with_error_mode
+    # QuotedFragment is more permissive than what Parser#expression allows.
+    template1 = "{% assign 5 = 'b' %}{% cycle .5, .4 %}"
+    template2 = "{% cycle .5: 'a', 'b' %}"
+
+    with_error_modes(:lax, :strict) do
+      assert_template_result("b", template1)
+      assert_template_result("a", template2)
+    end
+
+    with_error_modes(:strict2) do
+      error1 = assert_raises(Liquid::SyntaxError) { Template.parse(template1) }
+      error2 = assert_raises(Liquid::SyntaxError) { Template.parse(template2) }
+
+      expected_error = /Liquid syntax error: \[:dot, "."\] is not a valid expression/
+
+      assert_match(expected_error, error1.message)
+      assert_match(expected_error, error2.message)
+    end
+  end
+
+  def test_cycle_with_trailing_elements
+    assignments = "{% assign a = 'A' %}{% assign n = 'N' %}"
+
+    template1 = "#{assignments}{% cycle       'a'  'b', 'c' %}"
+    template2 = "#{assignments}{% cycle name: 'a'  'b', 'c' %}"
+    template3 = "#{assignments}{% cycle name: 'a', 'b'  'c' %}"
+    template4 = "#{assignments}{% cycle n  e: 'a', 'b', 'c' %}"
+    template5 = "#{assignments}{% cycle n  e  'a', 'b', 'c' %}"
+
+    with_error_modes(:lax, :strict) do
+      assert_template_result("a", template1)
+      assert_template_result("a", template2)
+      assert_template_result("a", template3)
+      assert_template_result("N", template4)
+      assert_template_result("N", template5)
+    end
+
+    with_error_modes(:strict2) do
+      error1 = assert_raises(Liquid::SyntaxError) { Template.parse(template1) }
+      error2 = assert_raises(Liquid::SyntaxError) { Template.parse(template2) }
+      error3 = assert_raises(Liquid::SyntaxError) { Template.parse(template3) }
+      error4 = assert_raises(Liquid::SyntaxError) { Template.parse(template4) }
+      error5 = assert_raises(Liquid::SyntaxError) { Template.parse(template5) }
+
+      expected_error = /Expected end_of_string but found/
+
+      assert_match(expected_error, error1.message)
+      assert_match(expected_error, error2.message)
+      assert_match(expected_error, error3.message)
+      assert_match(expected_error, error4.message)
+      assert_match(expected_error, error5.message)
+    end
+  end
+
+  def test_cycle_name_with_invalid_expression
+    template = <<~LIQUID
+      {% for i in (1..3) %}
+        {% cycle foo=>bar: "a", "b" %}
+      {% endfor %}
+    LIQUID
+
+    with_error_modes(:lax, :strict) do
+      refute_nil(Template.parse(template))
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
+
+  def test_cycle_variable_with_invalid_expression
+    template = <<~LIQUID
+      {% for i in (1..3) %}
+        {% cycle foo=>bar, "a", "b" %}
+      {% endfor %}
+    LIQUID
+
+    with_error_modes(:lax, :strict) do
+      refute_nil(Template.parse(template))
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/Unexpected character =/, error.message)
+    end
   end
 end

test/integration/tags/include_tag_test.rb

@@ -204,6 +204,32 @@ class IncludeTagTest < Minitest::Test
     )
   end
 
+  def test_strict2_parsing_errors
+    with_error_modes(:lax, :strict) do
+      assert_template_result(
+        'hello value1 value2',
+        '{% include "snippet" !!! arg1: "value1" ~~~ arg2: "value2" %}',
+        partials: { 'snippet' => 'hello {{ arg1 }} {{ arg2 }}' },
+      )
+    end
+
+    with_error_modes(:strict2) do
+      assert_syntax_error(
+        '{% include "snippet" !!! arg1: "value1" ~~~ arg2: "value2" %}',
+      )
+      assert_syntax_error(
+        '{% include "snippet" | filter %}',
+      )
+    end
+  end
+
+  def test_optional_commas
+    partials = { 'snippet' => 'hello {{ arg1 }} {{ arg2 }}' }
+    assert_template_result('hello value1 value2', '{% include "snippet", arg1: "value1", arg2: "value2" %}', partials: partials)
+    assert_template_result('hello value1 value2', '{% include "snippet"  arg1: "value1", arg2: "value2" %}', partials: partials)
+    assert_template_result('hello value1 value2', '{% include "snippet"  arg1: "value1"  arg2: "value2" %}', partials: partials)
+  end
+
   def test_include_tag_caches_second_read_of_same_partial
     file_system = CountingFileSystem.new
     environment = Liquid::Environment.build(file_system: file_system)
@@ -277,13 +303,13 @@ class IncludeTagTest < Minitest::Test
     assert_raises(Liquid::SyntaxError) do
       Template.parse("{% include template %}", error_mode: :strict, environment: env).render!("template" => '{{ "X" || downcase }}')
     end
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       assert_equal('x', Template.parse("{% include template %}", error_mode: :strict, include_options_blacklist: true, environment: env).render!("template" => '{{ "X" || downcase }}'))
     end
     assert_raises(Liquid::SyntaxError) do
       Template.parse("{% include template %}", error_mode: :strict, include_options_blacklist: [:locale], environment: env).render!("template" => '{{ "X" || downcase }}')
     end
-    with_error_mode(:lax) do
+    with_error_modes(:lax) do
       assert_equal('x', Template.parse("{% include template %}", error_mode: :strict, include_options_blacklist: [:error_mode], environment: env).render!("template" => '{{ "X" || downcase }}'))
     end
   end
@@ -374,4 +400,43 @@ class IncludeTagTest < Minitest::Test
       render_errors: true,
     )
   end
+
+  def test_include_template_with_invalid_expression
+    template = "{% include foo=>bar %}"
+
+    with_error_modes(:lax, :strict) do
+      refute_nil(Template.parse(template))
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
+
+  def test_include_with_invalid_expression
+    template = '{% include "snippet" with foo=>bar %}'
+
+    with_error_modes(:lax, :strict) do
+      refute_nil(Template.parse(template))
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
+
+  def test_include_attribute_with_invalid_expression
+    template = '{% include "snippet", key: foo=>bar %}'
+
+    with_error_modes(:lax, :strict) do
+      refute_nil(Template.parse(template))
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
 end # IncludeTagTest

test/integration/tags/render_tag_test.rb

@@ -105,7 +105,33 @@ class RenderTagTest < Minitest::Test
     assert_syntax_error("{% assign name = 'snippet' %}{% render name %}")
   end
 
-  def test_include_tag_caches_second_read_of_same_partial
+  def test_strict2_parsing_errors
+    with_error_modes(:lax, :strict) do
+      assert_template_result(
+        'hello value1 value2',
+        '{% render "snippet" !!! arg1: "value1" ~~~ arg2: "value2" %}',
+        partials: { 'snippet' => 'hello {{ arg1 }} {{ arg2 }}' },
+      )
+    end
+
+    with_error_modes(:strict2) do
+      assert_syntax_error(
+        '{% render "snippet" !!! arg1: "value1" ~~~ arg2: "value2" %}',
+      )
+      assert_syntax_error(
+        '{% render "snippet" | filter %}',
+      )
+    end
+  end
+
+  def test_optional_commas
+    partials = { 'snippet' => 'hello {{ arg1 }} {{ arg2 }}' }
+    assert_template_result('hello value1 value2', '{% render "snippet", arg1: "value1", arg2: "value2" %}', partials: partials)
+    assert_template_result('hello value1 value2', '{% render "snippet"  arg1: "value1", arg2: "value2" %}', partials: partials)
+    assert_template_result('hello value1 value2', '{% render "snippet"  arg1: "value1"  arg2: "value2" %}', partials: partials)
+  end
+
+  def test_render_tag_caches_second_read_of_same_partial
     file_system = StubFileSystem.new('snippet' => 'echo')
     assert_equal(
       'echoecho',
@@ -288,4 +314,30 @@ class RenderTagTest < Minitest::Test
       render_errors: true,
     )
   end
+
+  def test_render_with_invalid_expression
+    template = '{% render "snippet" with foo=>bar %}'
+
+    with_error_modes(:lax, :strict) do
+      refute_nil(Template.parse(template))
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
+
+  def test_render_attribute_with_invalid_expression
+    template = '{% render "snippet", key: foo=>bar %}'
+
+    with_error_modes(:lax, :strict) do
+      refute_nil(Template.parse(template))
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
 end

test/integration/tags/standard_tag_test.rb

@@ -117,7 +117,7 @@ class StandardTagTest < Minitest::Test
     assigns = { 'condition' => "bad string here" }
     assert_template_result(
       '',
-      '{% case condition %}{% when "string here" %} hit {% endcase %}',\
+      '{% case condition %}{% when "string here" %} hit {% endcase %}',
       assigns,
     )
   end

test/integration/tags/table_row_test.rb

@@ -138,7 +138,7 @@ class TableRowTest < Minitest::Test
 
   def test_tablerow_loop_drop_attributes
     template = <<~LIQUID.chomp
-      {% tablerow i in (1...2) %}
+      {% tablerow i in (1..2) %}
       col: {{ tablerowloop.col }}
       col0: {{ tablerowloop.col0 }}
       col_first: {{ tablerowloop.col_first }}
@@ -192,12 +192,14 @@ class TableRowTest < Minitest::Test
     assert_template_result(
       "Liquid error (line 1): invalid integer",
       '{% tablerow n in (1...10) limit:true %} {{n}} {% endtablerow %}',
+      error_mode: :warn,
       render_errors: true,
     )
 
     assert_template_result(
       "Liquid error (line 1): invalid integer",
       '{% tablerow n in (1...10) offset:true %} {{n}} {% endtablerow %}',
+      error_mode: :warn,
       render_errors: true,
     )
 
@@ -205,18 +207,19 @@ class TableRowTest < Minitest::Test
       "Liquid error (line 1): invalid integer",
       '{% tablerow n in (1...10) cols:true %} {{n}} {% endtablerow %}',
       render_errors: true,
+      error_mode: :warn,
     )
   end
 
   def test_table_row_handles_interrupts
     assert_template_result(
       "<tr class=\"row1\">\n<td class=\"col1\"> 1 </td></tr>\n",
-      '{% tablerow n in (1...3) cols:2 %} {{n}} {% break %} {{n}} {% endtablerow %}',
+      '{% tablerow n in (1..3) cols:2 %} {{n}} {% break %} {{n}} {% endtablerow %}',
     )
 
     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\"> 3 </td></tr>\n",
-      '{% tablerow n in (1...3) cols:2 %} {{n}} {% continue %} {{n}} {% endtablerow %}',
+      '{% tablerow n in (1..3) cols:2 %} {{n}} {% continue %} {{n}} {% endtablerow %}',
     )
   end
 
@@ -255,4 +258,211 @@ class TableRowTest < Minitest::Test
       template,
     )
   end
+
+  def test_tablerow_with_cols_attribute_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow i in (1..6) cols: 3 %}{{ i }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">1</td><td class="col2">2</td><td class="col3">3</td></tr>
+      <tr class="row2"><td class="col1">4</td><td class="col2">5</td><td class="col3">6</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template)
+    end
+  end
+
+  def test_tablerow_with_limit_attribute_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow i in (1..10) limit: 3 %}{{ i }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">1</td><td class="col2">2</td><td class="col3">3</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template)
+    end
+  end
+
+  def test_tablerow_with_offset_attribute_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow i in (1..5) offset: 2 %}{{ i }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">3</td><td class="col2">4</td><td class="col3">5</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template)
+    end
+  end
+
+  def test_tablerow_with_range_attribute_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow i in (1..3) range: (1..10) %}{{ i }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">1</td><td class="col2">2</td><td class="col3">3</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template)
+    end
+  end
+
+  def test_tablerow_with_multiple_attributes_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow i in (1..10) cols: 2, limit: 4, offset: 1 %}{{ i }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">2</td><td class="col2">3</td></tr>
+      <tr class="row2"><td class="col1">4</td><td class="col2">5</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template)
+    end
+  end
+
+  def test_tablerow_with_variable_collection_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow n in numbers cols: 2 %}{{ n }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">1</td><td class="col2">2</td></tr>
+      <tr class="row2"><td class="col1">3</td><td class="col2">4</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template, { 'numbers' => [1, 2, 3, 4] })
+    end
+  end
+
+  def test_tablerow_with_dotted_access_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow n in obj.numbers cols: 2 %}{{ n }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">1</td><td class="col2">2</td></tr>
+      <tr class="row2"><td class="col1">3</td><td class="col2">4</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template, { 'obj' => { 'numbers' => [1, 2, 3, 4] } })
+    end
+  end
+
+  def test_tablerow_with_bracketed_access_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow n in obj["numbers"] cols: 2 %}{{ n }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">10</td><td class="col2">20</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template, { 'obj' => { 'numbers' => [10, 20] } })
+    end
+  end
+
+  def test_tablerow_without_attributes_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow i in (1..3) %}{{ i }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <td class="col1">1</td><td class="col2">2</td><td class="col3">3</td></tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template)
+    end
+  end
+
+  def test_tablerow_without_in_keyword_in_strict2_mode
+    template = '{% tablerow i (1..10) %}{{ i }}{% endtablerow %}'
+
+    with_error_modes(:strict2) do
+      error = assert_raises(SyntaxError) { Template.parse(template) }
+      assert_equal("Liquid syntax error: For loops require an 'in' clause in \"i (1..10)\"", error.message)
+    end
+  end
+
+  def test_tablerow_with_multiple_invalid_attributes_reports_first_in_strict2_mode
+    template = '{% tablerow i in (1..10) invalid1: 5, invalid2: 10 %}{{ i }}{% endtablerow %}'
+
+    with_error_modes(:strict2) do
+      error = assert_raises(SyntaxError) { Template.parse(template) }
+      assert_equal("Liquid syntax error: Invalid attribute 'invalid1' in tablerow loop. Valid attributes are cols, limit, offset, and range in \"i in (1..10) invalid1: 5, invalid2: 10\"", error.message)
+    end
+  end
+
+  def test_tablerow_with_empty_collection_in_strict2_mode
+    template = <<~LIQUID.chomp
+      {% tablerow i in empty_array cols: 2 %}{{ i }}{% endtablerow %}
+    LIQUID
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      </tr>
+    OUTPUT
+
+    with_error_modes(:strict2) do
+      assert_template_result(expected, template, { 'empty_array' => [] })
+    end
+  end
+
+  def test_tablerow_with_invalid_attribute_strict_vs_strict2
+    template = '{% tablerow i in (1..5) invalid_attr: 10 %}{{ i }}{% endtablerow %}'
+
+    expected = <<~OUTPUT
+      <tr class="row1">
+      <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>
+    OUTPUT
+
+    with_error_modes(:lax, :strict) do
+      assert_template_result(expected, template)
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(SyntaxError) { Template.parse(template) }
+      assert_match(/Invalid attribute 'invalid_attr'/, error.message)
+    end
+  end
+
+  def test_tablerow_with_invalid_expression_strict_vs_strict2
+    template = '{% tablerow i in (1..5) limit: foo=>bar %}{{ i }}{% endtablerow %}'
+
+    with_error_modes(:lax, :strict) do
+      expected = <<~OUTPUT
+        <tr class="row1">
+        </tr>
+      OUTPUT
+      assert_template_result(expected, template)
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(SyntaxError) { Template.parse(template) }
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
 end

test/integration/template_test.rb

@@ -133,7 +133,7 @@ class TemplateTest < Minitest::Test
     assert(t.resource_limits.reached?)
 
     t.resource_limits.render_score_limit = 200
-    assert_equal((" foo " * 100), t.render!)
+    assert_equal(" foo " * 100, t.render!)
     refute_nil(t.resource_limits.render_score)
   end
 
@@ -179,6 +179,86 @@ class TemplateTest < Minitest::Test
     assert_equal("すごい", t.render)
   end
 
+  def test_cumulative_render_score_limit_across_render_tags
+    file_system = StubFileSystem.new(
+      'loop' => '{% for a in (1..10) %} foo {% endfor %}',
+    )
+    environment = Liquid::Environment.build(file_system: file_system)
+
+    # Without cumulative limit, all 5 partials render successfully
+    t = Template.parse(
+      '{% render "loop" %}{% render "loop" %}{% render "loop" %}{% render "loop" %}{% render "loop" %}',
+      environment: environment,
+    )
+    unlimited_output = t.render!
+    total_cumulative = t.resource_limits.cumulative_render_score
+
+    # With cumulative limit set below the total, rendering stops early
+    t2 = Template.parse(
+      '{% render "loop" %}{% render "loop" %}{% render "loop" %}{% render "loop" %}{% render "loop" %}',
+      environment: environment,
+    )
+    t2.resource_limits.cumulative_render_score_limit = total_cumulative / 2
+    limited_output = t2.render
+    assert(t2.resource_limits.reached?)
+    assert_operator(limited_output.length, :<, unlimited_output.length)
+  end
+
+  def test_cumulative_render_score_limit_raises_on_render_bang
+    file_system = StubFileSystem.new(
+      'loop' => '{% for a in (1..10) %} foo {% endfor %}',
+    )
+    environment = Liquid::Environment.build(file_system: file_system)
+    t = Template.parse(
+      '{% render "loop" %}{% render "loop" %}{% render "loop" %}{% render "loop" %}{% render "loop" %}',
+      environment: environment,
+    )
+    t.resource_limits.cumulative_render_score_limit = 20
+    assert_raises(Liquid::MemoryError) do
+      t.render!
+    end
+  end
+
+  def test_cumulative_assign_score_limit_across_include_tags
+    file_system = StubFileSystem.new(
+      'assign_partial' => '{% assign x = "a long string value here" %}',
+    )
+    environment = Liquid::Environment.build(file_system: file_system)
+
+    # Without cumulative limit, all 5 partials render
+    t = Template.parse(
+      '{% include "assign_partial" %}{% include "assign_partial" %}{% include "assign_partial" %}{% include "assign_partial" %}{% include "assign_partial" %}',
+      environment: environment,
+    )
+    t.render!
+    total_cumulative = t.resource_limits.cumulative_assign_score
+
+    # With cumulative limit set below the total, rendering stops early
+    t2 = Template.parse(
+      '{% include "assign_partial" %}{% include "assign_partial" %}{% include "assign_partial" %}{% include "assign_partial" %}{% include "assign_partial" %}',
+      environment: environment,
+    )
+    t2.resource_limits.cumulative_assign_score_limit = total_cumulative / 2
+    t2.render
+    assert(t2.resource_limits.reached?)
+  end
+
+  def test_cumulative_render_score_tracks_across_partials_without_limit
+    file_system = StubFileSystem.new(
+      'loop' => '{% for a in (1..10) %} foo {% endfor %}',
+    )
+    environment = Liquid::Environment.build(file_system: file_system)
+    t = Template.parse(
+      '{% render "loop" %}{% render "loop" %}{% render "loop" %}',
+      environment: environment,
+    )
+    t.render!
+    assert(
+      t.resource_limits.cumulative_render_score > t.resource_limits.render_score,
+      "cumulative should exceed per-template score after multiple partials",
+    )
+  end
+
   def test_default_resource_limits_unaffected_by_render_with_context
     context = Context.new
     t = Template.parse("{% for a in (1..100) %}x{% assign foo = 1 %} {% endfor %}")

test/integration/variable_test.rb

@@ -209,4 +209,69 @@ class VariableTest < Minitest::Test
       end
     end
   end
+
+  def test_filter_with_single_trailing_comma
+    template = '{{ "hello" | append: "world", }}'
+
+    with_error_modes(:strict) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/is not a valid expression/, error.message)
+    end
+
+    with_error_modes(:strict2) do
+      assert_template_result('helloworld', template)
+    end
+  end
+
+  def test_multiple_filters_with_trailing_commas
+    template = '{{ "hello" | append: "1", | append: "2", }}'
+
+    with_error_modes(:strict) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/is not a valid expression/, error.message)
+    end
+
+    with_error_modes(:strict2) do
+      assert_template_result('hello12', template)
+    end
+  end
+
+  def test_filter_with_colon_but_no_arguments
+    template = '{{ "test" | upcase: }}'
+
+    with_error_modes(:strict) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/is not a valid expression/, error.message)
+    end
+
+    with_error_modes(:strict2) do
+      assert_template_result('TEST', template)
+    end
+  end
+
+  def test_filter_chain_with_colon_no_args
+    template = '{{ "test" | append: "x" | upcase: }}'
+
+    with_error_modes(:strict) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/is not a valid expression/, error.message)
+    end
+
+    with_error_modes(:strict2) do
+      assert_template_result('TESTX', template)
+    end
+  end
+
+  def test_combining_trailing_comma_and_empty_args
+    template = '{{ "test" | append: "x", | upcase: }}'
+
+    with_error_modes(:strict) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+      assert_match(/is not a valid expression/, error.message)
+    end
+
+    with_error_modes(:strict2) do
+      assert_template_result('TESTX', template)
+    end
+  end
 end

test/test_helper.rb

@@ -34,7 +34,7 @@ module Minitest
 
     def assert_template_result(
       expected, template, assigns = {},
-      message: nil, partials: nil, error_mode: nil, render_errors: false,
+      message: nil, partials: nil, error_mode: Liquid::Environment.default.error_mode, render_errors: false,
       template_factory: nil
     )
       file_system = StubFileSystem.new(partials || {})
@@ -82,10 +82,12 @@ module Minitest
       Environment.dangerously_override(environment, &blk)
     end
 
-    def with_error_mode(mode)
+    def with_error_modes(*modes)
       old_mode = Liquid::Environment.default.error_mode
-      Liquid::Environment.default.error_mode = mode
-      yield
+      modes.each do |mode|
+        Liquid::Environment.default.error_mode = mode
+        yield
+      end
     ensure
       Liquid::Environment.default.error_mode = old_mode
     end
@@ -197,6 +199,26 @@ class ErrorDrop < Liquid::Drop
   end
 end
 
+class CustomToLiquidDrop < Liquid::Drop
+  def initialize(value)
+    @value = value
+    super()
+  end
+
+  def to_liquid
+    @value
+  end
+end
+
+class HashWithCustomToS < Hash
+  def to_s
+    "kewl"
+  end
+end
+
+class HashWithoutCustomToS < Hash
+end
+
 class StubFileSystem
   attr_reader :file_read_count
 

test/unit/condition_unit_test.rb

@@ -161,11 +161,208 @@ class ConditionUnitTest < Minitest::Test
       assert_equal(true, Condition.new(1, '==', 1).evaluate)
     end
 
-    expected = "DEPRECATION WARNING: Condition#evaluate without a context argument is deprecated" \
-      " and will be removed from Liquid 6.0.0."
+    expected = "DEPRECATION WARNING: Condition#evaluate without a context argument is deprecated " \
+      "and will be removed from Liquid 6.0.0."
     assert_includes(err.lines.map(&:strip), expected)
   end
 
+  def test_parse_expression_in_strict_mode
+    environment = Environment.build(error_mode: :strict)
+    parse_context = ParseContext.new(environment: environment)
+    result = Condition.parse_expression(parse_context, 'product.title')
+
+    assert_instance_of(VariableLookup, result)
+    assert_equal('product', result.name)
+    assert_equal(['title'], result.lookups)
+  end
+
+  def test_parse_expression_in_strict2_mode_raises_internal_error
+    environment = Environment.build(error_mode: :strict2)
+    parse_context = ParseContext.new(environment: environment)
+
+    error = assert_raises(Liquid::InternalError) do
+      Condition.parse_expression(parse_context, 'product.title')
+    end
+
+    assert_match(/unsafe parse_expression cannot be used in strict2 mode/, error.message)
+  end
+
+  def test_parse_expression_with_safe_true_in_strict2_mode
+    environment = Environment.build(error_mode: :strict2)
+    parse_context = ParseContext.new(environment: environment)
+    result = Condition.parse_expression(parse_context, 'product.title', safe: true)
+
+    assert_instance_of(VariableLookup, result)
+    assert_equal('product', result.name)
+    assert_equal(['title'], result.lookups)
+  end
+
+  # Tests for blank? comparison without ActiveSupport
+  #
+  # Ruby's standard library does not include blank? on String, Array, Hash, etc.
+  # ActiveSupport adds blank? but Liquid must work without it. These tests verify
+  # that Liquid implements blank? semantics internally for use in templates like:
+  #   {% if x == blank %}...{% endif %}
+  #
+  # The blank? semantics match ActiveSupport's behavior:
+  # - nil and false are blank
+  # - Strings are blank if empty or contain only whitespace
+  # - Arrays and Hashes are blank if empty
+  # - true and numbers are never blank
+
+  def test_blank_with_whitespace_string
+    # Template authors expect "   " to be blank since it has no visible content.
+    # This matches ActiveSupport's String#blank? which returns true for whitespace-only strings.
+    @context['whitespace'] = '   '
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_true(VariableLookup.new('whitespace'), '==', blank_literal)
+  end
+
+  def test_blank_with_empty_string
+    # An empty string has no content, so it should be considered blank.
+    # This is the most basic case of a blank string.
+    @context['empty_string'] = ''
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_true(VariableLookup.new('empty_string'), '==', blank_literal)
+  end
+
+  def test_blank_with_empty_array
+    # Empty arrays have no elements, so they are blank.
+    # Useful for checking if a collection has items: {% if products == blank %}
+    @context['empty_array'] = []
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_true(VariableLookup.new('empty_array'), '==', blank_literal)
+  end
+
+  def test_blank_with_empty_hash
+    # Empty hashes have no key-value pairs, so they are blank.
+    # Useful for checking if settings/options exist: {% if settings == blank %}
+    @context['empty_hash'] = {}
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_true(VariableLookup.new('empty_hash'), '==', blank_literal)
+  end
+
+  def test_blank_with_nil
+    # nil represents "nothing" and is the canonical blank value.
+    # Unassigned variables resolve to nil, so this enables: {% if missing_var == blank %}
+    @context['nil_value'] = nil
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_true(VariableLookup.new('nil_value'), '==', blank_literal)
+  end
+
+  def test_blank_with_false
+    # false is considered blank to match ActiveSupport semantics.
+    # This allows {% if some_flag == blank %} to work when flag is false.
+    @context['false_value'] = false
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_true(VariableLookup.new('false_value'), '==', blank_literal)
+  end
+
+  def test_not_blank_with_true
+    # true is a definite value, not blank.
+    # Ensures {% if flag == blank %} works correctly for boolean flags.
+    @context['true_value'] = true
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_false(VariableLookup.new('true_value'), '==', blank_literal)
+  end
+
+  def test_not_blank_with_number
+    # Numbers (including zero) are never blank - they represent actual values.
+    # 0 is a valid quantity, not the absence of a value.
+    @context['number'] = 42
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_false(VariableLookup.new('number'), '==', blank_literal)
+  end
+
+  def test_not_blank_with_string_content
+    # A string with actual content is not blank.
+    # This is the expected behavior for most template string comparisons.
+    @context['string'] = 'hello'
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_false(VariableLookup.new('string'), '==', blank_literal)
+  end
+
+  def test_not_blank_with_non_empty_array
+    # An array with elements has content, so it's not blank.
+    # Enables patterns like {% unless products == blank %}Show products{% endunless %}
+    @context['array'] = [1, 2, 3]
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_false(VariableLookup.new('array'), '==', blank_literal)
+  end
+
+  def test_not_blank_with_non_empty_hash
+    # A hash with key-value pairs has content, so it's not blank.
+    # Useful for checking if configuration exists: {% if config != blank %}
+    @context['hash'] = { 'a' => 1 }
+    blank_literal = Condition.class_variable_get(:@@method_literals)['blank']
+
+    assert_evaluates_false(VariableLookup.new('hash'), '==', blank_literal)
+  end
+
+  # Tests for empty? comparison without ActiveSupport
+  #
+  # empty? is distinct from blank? - it only checks if a collection has zero elements.
+  # For strings, empty? checks length == 0, NOT whitespace content.
+  # Ruby's standard library has empty? on String, Array, and Hash, but Liquid
+  # provides a fallback implementation for consistency.
+
+  def test_empty_with_empty_string
+    # An empty string ("") has length 0, so it's empty.
+    # Different from blank - empty is a stricter check.
+    @context['empty_string'] = ''
+    empty_literal = Condition.class_variable_get(:@@method_literals)['empty']
+
+    assert_evaluates_true(VariableLookup.new('empty_string'), '==', empty_literal)
+  end
+
+  def test_empty_with_whitespace_string_not_empty
+    # Whitespace strings have length > 0, so they are NOT empty.
+    # This is the key difference between empty and blank:
+    # "   ".empty? => false, but "   ".blank? => true
+    @context['whitespace'] = '   '
+    empty_literal = Condition.class_variable_get(:@@method_literals)['empty']
+
+    assert_evaluates_false(VariableLookup.new('whitespace'), '==', empty_literal)
+  end
+
+  def test_empty_with_empty_array
+    # An array with no elements is empty.
+    # [].empty? => true
+    @context['empty_array'] = []
+    empty_literal = Condition.class_variable_get(:@@method_literals)['empty']
+
+    assert_evaluates_true(VariableLookup.new('empty_array'), '==', empty_literal)
+  end
+
+  def test_empty_with_empty_hash
+    # A hash with no key-value pairs is empty.
+    # {}.empty? => true
+    @context['empty_hash'] = {}
+    empty_literal = Condition.class_variable_get(:@@method_literals)['empty']
+
+    assert_evaluates_true(VariableLookup.new('empty_hash'), '==', empty_literal)
+  end
+
+  def test_nil_is_not_empty
+    # nil is NOT empty - empty? checks if a collection has zero elements.
+    # nil is not a collection, so it cannot be empty.
+    # This differs from blank: nil IS blank, but nil is NOT empty.
+    @context['nil_value'] = nil
+    empty_literal = Condition.class_variable_get(:@@method_literals)['empty']
+
+    assert_evaluates_false(VariableLookup.new('nil_value'), '==', empty_literal)
+  end
+
   private
 
   def assert_evaluates_true(left, op, right)

test/unit/environment_test.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class EnvironmentTest < Minitest::Test
+  include Liquid
+
+  class UnsubscribeFooter < Liquid::Tag
+    def render(_context)
+      'Unsubscribe Footer'
+    end
+  end
+
+  def test_custom_tag
+    email_environment = Liquid::Environment.build do |environment|
+      environment.register_tag("unsubscribe_footer", UnsubscribeFooter)
+    end
+
+    assert(email_environment.tags["unsubscribe_footer"])
+    assert(email_environment.tag_for_name("unsubscribe_footer"))
+    template = Liquid::Template.parse("{% unsubscribe_footer %}", environment: email_environment)
+
+    assert_equal('Unsubscribe Footer', template.render)
+  end
+end

test/unit/fast_path_unit_test.rb

@@ -0,0 +1,256 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+# Tests for the byte-walking fast paths introduced in the ByteTables optimization.
+# Each fast path is tested for equivalence with the original regex-based code path
+# it replaces, covering accepted inputs, rejected inputs, and boundary cases.
+class FastPathUnitTest < Minitest::Test
+  # ── Expression.parse_number ────────────────────────────────────────
+  # Fast path: byte-walk with ByteTables::DIGIT
+  # Replaces: INTEGER_REGEX, FLOAT_REGEX, StringScanner loop
+
+  def test_parse_number_simple_integers
+    assert_equal(42, Liquid::Expression.parse_number("42"))
+    assert_equal(0, Liquid::Expression.parse_number("0"))
+    assert_equal(999, Liquid::Expression.parse_number("999"))
+  end
+
+  def test_parse_number_negative_integers
+    assert_equal(-7, Liquid::Expression.parse_number("-7"))
+    assert_equal(-0, Liquid::Expression.parse_number("-0"))
+    assert_equal(-123, Liquid::Expression.parse_number("-123"))
+  end
+
+  def test_parse_number_simple_floats
+    assert_equal(3.14, Liquid::Expression.parse_number("3.14"))
+    assert_equal(0.5, Liquid::Expression.parse_number("0.5"))
+    assert_equal(-0.5, Liquid::Expression.parse_number("-0.5"))
+    assert_equal(100.0, Liquid::Expression.parse_number("100.0"))
+  end
+
+  def test_parse_number_trailing_dot
+    # "123." → 123.0 (truncate before dot)
+    assert_equal(123.0, Liquid::Expression.parse_number("123."))
+    assert_equal(0.0, Liquid::Expression.parse_number("0."))
+  end
+
+  def test_parse_number_multi_dot_floats
+    # "1.2.3" → 1.2 (truncate at second dot)
+    assert_equal(1.2, Liquid::Expression.parse_number("1.2.3"))
+    assert_equal(1.2, Liquid::Expression.parse_number("1.2.3.4"))
+    assert_equal(0.0, Liquid::Expression.parse_number("0.0.0"))
+  end
+
+  def test_parse_number_rejects_non_numeric
+    assert_nil(Liquid::Expression.parse_number("hello"))
+    assert_nil(Liquid::Expression.parse_number(""))
+    assert_nil(Liquid::Expression.parse_number("abc123"))
+    assert_nil(Liquid::Expression.parse_number(".5"))
+    assert_nil(Liquid::Expression.parse_number("-.5"))
+  end
+
+  def test_parse_number_rejects_trailing_alpha_after_multi_dot
+    # "1.2.3a" must be nil, not 1.2 — these are not valid numbers
+    assert_nil(Liquid::Expression.parse_number("1.2.3a"))
+    assert_nil(Liquid::Expression.parse_number("1.2.3.4a"))
+    assert_nil(Liquid::Expression.parse_number("1.2.34a"))
+    assert_nil(Liquid::Expression.parse_number("-1.2.3a"))
+  end
+
+  def test_parse_number_rejects_bare_dash
+    assert_nil(Liquid::Expression.parse_number("-"))
+    assert_nil(Liquid::Expression.parse_number("-a"))
+  end
+
+  # ── Expression.parse strip guard ───────────────────────────────────
+  # Fast path: skip String#strip when no leading/trailing whitespace
+  # Must produce identical results to unconditional .strip
+
+  def test_parse_strips_leading_whitespace
+    assert_equal(42, Liquid::Expression.parse("  42"))
+    assert_equal(42, Liquid::Expression.parse("\t42"))
+    assert_equal(42, Liquid::Expression.parse("\n42"))
+  end
+
+  def test_parse_strips_trailing_whitespace
+    assert_equal(42, Liquid::Expression.parse("42  "))
+    assert_equal(42, Liquid::Expression.parse("42\t"))
+    assert_equal(42, Liquid::Expression.parse("42\n"))
+  end
+
+  def test_parse_strips_both_sides
+    assert_equal(42, Liquid::Expression.parse("  42  "))
+    assert_equal("hello", Liquid::Expression.parse("  'hello'  "))
+  end
+
+  def test_parse_no_strip_needed
+    assert_equal(42, Liquid::Expression.parse("42"))
+    assert_equal("hello", Liquid::Expression.parse("'hello'"))
+    assert_equal(true, Liquid::Expression.parse("true"))
+  end
+
+  def test_parse_strips_null_bytes
+    # String#strip removes \x00 — the WHITESPACE table must match
+    assert_equal(true, Liquid::Expression.parse("\x00true"))
+    assert_equal(true, Liquid::Expression.parse("true\x00"))
+  end
+
+  # ── VariableLookup.simple_lookup? ──────────────────────────────────
+  # Fast path: regex gate for simple a.b.c chains
+  # Must accept only inputs the byte-walk can handle correctly
+
+  def test_simple_lookup_accepts_single_names
+    assert(Liquid::VariableLookup.simple_lookup?("product"))
+    assert(Liquid::VariableLookup.simple_lookup?("x"))
+    assert(Liquid::VariableLookup.simple_lookup?("_private"))
+  end
+
+  def test_simple_lookup_accepts_dotted_chains
+    assert(Liquid::VariableLookup.simple_lookup?("product.title"))
+    assert(Liquid::VariableLookup.simple_lookup?("a.b.c.d"))
+  end
+
+  def test_simple_lookup_accepts_question_marks
+    assert(Liquid::VariableLookup.simple_lookup?("product.available?"))
+    assert(Liquid::VariableLookup.simple_lookup?("empty?"))
+  end
+
+  def test_simple_lookup_accepts_hyphens
+    assert(Liquid::VariableLookup.simple_lookup?("my-var"))
+    assert(Liquid::VariableLookup.simple_lookup?("my-var.some-field"))
+  end
+
+  def test_simple_lookup_rejects_brackets
+    refute(Liquid::VariableLookup.simple_lookup?("product[0]"))
+    refute(Liquid::VariableLookup.simple_lookup?("hash['key']"))
+    refute(Liquid::VariableLookup.simple_lookup?("[0]"))
+  end
+
+  def test_simple_lookup_rejects_empty_and_malformed
+    refute(Liquid::VariableLookup.simple_lookup?(""))
+    refute(Liquid::VariableLookup.simple_lookup?(".leading"))
+    refute(Liquid::VariableLookup.simple_lookup?("trailing."))
+    refute(Liquid::VariableLookup.simple_lookup?("a..b"))
+  end
+
+  # ── VariableLookup fast path equivalence ───────────────────────────
+  # The fast path must produce identical name, lookups, and command_flags
+  # to the original VariableParser regex path
+
+  def test_fast_path_simple_name
+    vl = Liquid::VariableLookup.new("product")
+    assert_equal("product", vl.name)
+    assert_equal([], vl.lookups)
+  end
+
+  def test_fast_path_dotted_chain
+    vl = Liquid::VariableLookup.new("product.title")
+    assert_equal("product", vl.name)
+    assert_equal(["title"], vl.lookups)
+  end
+
+  def test_fast_path_deep_chain
+    vl = Liquid::VariableLookup.new("a.b.c.d")
+    assert_equal("a", vl.name)
+    assert_equal(["b", "c", "d"], vl.lookups)
+  end
+
+  def test_fast_path_command_methods
+    vl = Liquid::VariableLookup.new("items.size")
+    assert_equal("items", vl.name)
+    assert_equal(["size"], vl.lookups)
+    assert(vl.lookup_command?(0))
+
+    vl2 = Liquid::VariableLookup.new("items.first")
+    assert(vl2.lookup_command?(0))
+
+    vl3 = Liquid::VariableLookup.new("items.last")
+    assert(vl3.lookup_command?(0))
+  end
+
+  def test_fast_path_non_command_lookups
+    vl = Liquid::VariableLookup.new("product.title")
+    refute(vl.lookup_command?(0))
+  end
+
+  def test_fast_path_question_mark
+    vl = Liquid::VariableLookup.new("product.available?")
+    assert_equal("product", vl.name)
+    assert_equal(["available?"], vl.lookups)
+  end
+
+  def test_bracket_lookup_falls_to_regex_path
+    vl = Liquid::VariableLookup.new("product[0]")
+    assert_equal("product", vl.name)
+    assert_equal([0], vl.lookups)
+  end
+
+  # ── BlockBody.try_parse_tag_token ──────────────────────────────────
+  # Fast path: byte-walk tag tokens instead of FullToken regex
+  # Must produce identical [tag_name, markup, newline_count] or nil
+
+  def test_tag_token_simple
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{% if x %}")
+    assert_equal(["if", "x ", 0], result)
+  end
+
+  def test_tag_token_whitespace_control_leading
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{%- if x %}")
+    assert_equal(["if", "x ", 0], result)
+  end
+
+  def test_tag_token_whitespace_control_trailing
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{% if x -%}")
+    assert_equal(["if", "x ", 0], result)
+  end
+
+  def test_tag_token_whitespace_control_both
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{%- if x -%}")
+    assert_equal(["if", "x ", 0], result)
+  end
+
+  def test_tag_token_no_markup
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{% endif %}")
+    assert_equal(["endif", "", 0], result)
+  end
+
+  def test_tag_token_hash_comment
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{% # this is a comment %}")
+    assert_equal(["#", "this is a comment ", 0], result)
+  end
+
+  def test_tag_token_with_newlines
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{% \n if \n x %}")
+    assert_equal(["if", "x ", 2], result)
+  end
+
+  def test_tag_token_hyphenated_name_stops_at_hyphen
+    # TagName = /\w+/ does not include hyphens
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{% my-tag markup %}")
+    assert_equal("my", result[0])
+  end
+
+  def test_tag_token_complex_markup
+    body = Liquid::BlockBody.new
+    result = body.send(:try_parse_tag_token, "{% for item in collection reversed %}")
+    assert_equal("for", result[0])
+    assert_equal("item in collection reversed ", result[1])
+  end
+
+  def test_tag_token_malformed_returns_nil
+    body = Liquid::BlockBody.new
+    # Token too short
+    assert_nil(body.send(:try_parse_tag_token, "{%"))
+    # No valid tag name start (digit)
+    assert_nil(body.send(:try_parse_tag_token, "{% 123 %}"))
+  end
+end

test/unit/parse_context_unit_test.rb

@@ -0,0 +1,123 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class ParseContextUnitTest < Minitest::Test
+  include Liquid
+
+  def test_safe_parse_expression_with_variable_lookup
+    parser_strict = strict_parse_context.new_parser('product.title')
+    result_strict = strict_parse_context.safe_parse_expression(parser_strict)
+
+    parser_strict2 = strict2_parse_context.new_parser('product.title')
+    result_strict2 = strict2_parse_context.safe_parse_expression(parser_strict2)
+
+    assert_instance_of(VariableLookup, result_strict)
+    assert_equal('product', result_strict.name)
+    assert_equal(['title'], result_strict.lookups)
+
+    assert_instance_of(VariableLookup, result_strict2)
+    assert_equal('product', result_strict2.name)
+    assert_equal(['title'], result_strict2.lookups)
+  end
+
+  def test_safe_parse_expression_raises_syntax_error_for_invalid_expression
+    parser_strict = strict_parse_context.new_parser('')
+    parser_strict2 = strict2_parse_context.new_parser('')
+
+    error_strict = assert_raises(Liquid::SyntaxError) do
+      strict_parse_context.safe_parse_expression(parser_strict)
+    end
+    assert_match(/is not a valid expression/, error_strict.message)
+
+    error_strict2 = assert_raises(Liquid::SyntaxError) do
+      strict2_parse_context.safe_parse_expression(parser_strict2)
+    end
+
+    assert_match(/is not a valid expression/, error_strict2.message)
+  end
+
+  def test_parse_expression_with_variable_lookup
+    result_strict = strict_parse_context.parse_expression('product.title')
+
+    assert_instance_of(VariableLookup, result_strict)
+    assert_equal('product', result_strict.name)
+    assert_equal(['title'], result_strict.lookups)
+
+    error = assert_raises(Liquid::InternalError) do
+      strict2_parse_context.parse_expression('product.title')
+    end
+
+    assert_match(/unsafe parse_expression cannot be used in strict2 mode/, error.message)
+  end
+
+  def test_parse_expression_with_safe_true
+    result_strict = strict_parse_context.parse_expression('product.title', safe: true)
+
+    assert_instance_of(VariableLookup, result_strict)
+    assert_equal('product', result_strict.name)
+    assert_equal(['title'], result_strict.lookups)
+
+    result_strict2 = strict2_parse_context.parse_expression('product.title', safe: true)
+
+    assert_instance_of(VariableLookup, result_strict2)
+    assert_equal('product', result_strict2.name)
+    assert_equal(['title'], result_strict2.lookups)
+  end
+
+  def test_parse_expression_with_empty_string
+    result_strict = strict_parse_context.parse_expression('')
+    assert_nil(result_strict)
+
+    error = assert_raises(Liquid::InternalError) do
+      strict2_parse_context.parse_expression('')
+    end
+
+    assert_match(/unsafe parse_expression cannot be used in strict2 mode/, error.message)
+  end
+
+  def test_parse_expression_with_empty_string_and_safe_true
+    result_strict = strict_parse_context.parse_expression('', safe: true)
+    assert_nil(result_strict)
+
+    result_strict2 = strict2_parse_context.parse_expression('', safe: true)
+    assert_nil(result_strict2)
+  end
+
+  def test_safe_parse_expression_advances_parser_pointer
+    parser = strict2_parse_context.new_parser('foo, bar')
+
+    # safe_parse_expression consumes "foo"
+    first_result = strict2_parse_context.safe_parse_expression(parser)
+    assert_instance_of(VariableLookup, first_result)
+    assert_equal('foo', first_result.name)
+
+    parser.consume(:comma)
+
+    # safe_parse_expression consumes "bar"
+    second_result = strict2_parse_context.safe_parse_expression(parser)
+    assert_instance_of(VariableLookup, second_result)
+    assert_equal('bar', second_result.name)
+
+    parser.consume(:end_of_string)
+  end
+
+  def test_parse_expression_with_whitespace_in_strict2_mode
+    result = strict2_parse_context.parse_expression('   ', safe: true)
+    assert_nil(result)
+  end
+
+  private
+
+  def strict_parse_context
+    @strict_parse_context ||= ParseContext.new(
+      environment: Environment.build(error_mode: :strict),
+    )
+  end
+
+  def strict2_parse_context
+    @strict2_parse_context ||= ParseContext.new(
+      environment: Environment.build(error_mode: :strict2),
+    )
+  end
+end

test/unit/partial_cache_unit_test.rb

@@ -184,7 +184,7 @@ class PartialCacheUnitTest < Minitest::Test
       },
     )
 
-    [:lax, :warn, :strict].each do |error_mode|
+    [:lax, :warn, :strict, :strict2].each do |error_mode|
       Liquid::PartialCache.load(
         'my_partial',
         context: context,
@@ -193,7 +193,7 @@ class PartialCacheUnitTest < Minitest::Test
     end
 
     assert_equal(
-      ["my_partial:lax", "my_partial:warn", "my_partial:strict"],
+      ["my_partial:lax", "my_partial:warn", "my_partial:strict", "my_partial:strict2"],
       context.registers[:cached_partials].keys,
     )
   end

test/unit/resource_limits_unit_test.rb

@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+class ResourceLimitsUnitTest < Minitest::Test
+  def test_cumulative_scores_initialize_to_zero
+    limits = Liquid::ResourceLimits.new({})
+    assert_equal(0, limits.cumulative_render_score)
+    assert_equal(0, limits.cumulative_assign_score)
+  end
+
+  def test_cumulative_limits_default_to_nil
+    limits = Liquid::ResourceLimits.new({})
+    assert_nil(limits.cumulative_render_score_limit)
+    assert_nil(limits.cumulative_assign_score_limit)
+  end
+
+  def test_cumulative_limits_configurable_via_hash
+    limits = Liquid::ResourceLimits.new(
+      cumulative_render_score_limit: 500,
+      cumulative_assign_score_limit: 300,
+    )
+    assert_equal(500, limits.cumulative_render_score_limit)
+    assert_equal(300, limits.cumulative_assign_score_limit)
+  end
+
+  def test_cumulative_limits_configurable_via_accessor
+    limits = Liquid::ResourceLimits.new({})
+    limits.cumulative_render_score_limit = 500
+    assert_equal(500, limits.cumulative_render_score_limit)
+  end
+
+  def test_cumulative_scores_survive_reset
+    limits = Liquid::ResourceLimits.new({})
+    limits.increment_render_score(10)
+    limits.increment_assign_score(5)
+
+    limits.reset
+
+    assert_equal(0, limits.render_score)
+    assert_equal(0, limits.assign_score)
+    assert_equal(10, limits.cumulative_render_score)
+    assert_equal(5, limits.cumulative_assign_score)
+  end
+
+  def test_cumulative_scores_accumulate_across_resets
+    limits = Liquid::ResourceLimits.new({})
+    limits.increment_render_score(10)
+    limits.reset
+    limits.increment_render_score(20)
+    limits.reset
+    limits.increment_render_score(30)
+
+    assert_equal(30, limits.render_score)
+    assert_equal(60, limits.cumulative_render_score)
+  end
+
+  def test_cumulative_render_score_limit_raises
+    limits = Liquid::ResourceLimits.new(cumulative_render_score_limit: 25)
+    limits.increment_render_score(10)
+    limits.reset
+    limits.increment_render_score(10)
+    limits.reset
+
+    assert_raises(Liquid::MemoryError) do
+      limits.increment_render_score(10)
+    end
+    assert(limits.reached?)
+  end
+
+  def test_cumulative_assign_score_limit_raises
+    limits = Liquid::ResourceLimits.new(cumulative_assign_score_limit: 15)
+    limits.increment_assign_score(8)
+    limits.reset
+
+    assert_raises(Liquid::MemoryError) do
+      limits.increment_assign_score(8)
+    end
+    assert(limits.reached?)
+  end
+
+  def test_per_template_limits_still_work_with_cumulative
+    limits = Liquid::ResourceLimits.new(
+      render_score_limit: 50,
+      cumulative_render_score_limit: 1000,
+    )
+    assert_raises(Liquid::MemoryError) do
+      limits.increment_render_score(51)
+    end
+  end
+end

test/unit/strainer_template_unit_test.rb

@@ -8,7 +8,7 @@ class StrainerTemplateUnitTest < Minitest::Test
   def test_add_filter_when_wrong_filter_class
     c = Context.new
     s = c.strainer
-    wrong_filter = ->(v) { v.reverse }
+    wrong_filter = lambda(&:reverse)
 
     exception = assert_raises(TypeError) do
       s.class.add_filter(wrong_filter)

test/unit/tags/case_tag_unit_test.rb

@@ -9,4 +9,140 @@ class CaseTagUnitTest < Minitest::Test
     template = Liquid::Template.parse('{% case var %}{% when true %}WHEN{% else %}ELSE{% endcase %}')
     assert_equal(['WHEN', 'ELSE'], template.root.nodelist[0].nodelist.map(&:nodelist).flatten)
   end
+
+  def test_case_with_trailing_element
+    template = <<~LIQUID
+      {%- case 1 bar -%}
+        {%- when 1 -%}
+          one
+        {%- else -%}
+          two
+      {%- endcase -%}
+    LIQUID
+
+    with_error_modes(:lax, :strict) do
+      assert_template_result("one", template)
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+
+      assert_match(/Expected end_of_string but found/, error.message)
+    end
+  end
+
+  def test_case_when_with_trailing_element
+    template = <<~LIQUID
+      {%- case 1 -%}
+        {%- when 1 bar -%}
+          one
+        {%- else -%}
+          two
+      {%- endcase -%}
+    LIQUID
+
+    with_error_modes(:lax, :strict) do
+      assert_template_result("one", template)
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+
+      assert_match(/Expected end_of_string but found/, error.message)
+    end
+  end
+
+  def test_case_when_with_comma
+    template = <<~LIQUID
+      {%- case 1 -%}
+        {%- when 2, 1 -%}
+          one
+        {%- else -%}
+          two
+      {%- endcase -%}
+    LIQUID
+
+    with_error_modes(:lax, :strict, :strict2) do
+      assert_template_result("one", template)
+    end
+  end
+
+  def test_case_when_with_or
+    template = <<~LIQUID
+      {%- case 1 -%}
+        {%- when 2 or 1 -%}
+          one
+        {%- else -%}
+          two
+      {%- endcase -%}
+    LIQUID
+
+    with_error_modes(:lax, :strict, :strict2) do
+      assert_template_result("one", template)
+    end
+  end
+
+  def test_case_when_empty
+    template = <<~LIQUID
+      {%- case x -%}
+        {%- when 2 or empty -%}
+          2 or empty
+        {%- else -%}
+          not 2 or empty
+      {%- endcase -%}
+    LIQUID
+
+    with_error_modes(:lax, :strict, :strict2) do
+      assert_template_result("2 or empty", template, { 'x' => 2 })
+      assert_template_result("2 or empty", template, { 'x' => {} })
+      assert_template_result("2 or empty", template, { 'x' => [] })
+      assert_template_result("not 2 or empty", template, { 'x' => { 'a' => 'b' } })
+      assert_template_result("not 2 or empty", template, { 'x' => ['a'] })
+      assert_template_result("not 2 or empty", template, { 'x' => 4 })
+    end
+  end
+
+  def test_case_with_invalid_expression
+    template = <<~LIQUID
+      {%- case foo=>bar -%}
+        {%- when 'baz' -%}
+          one
+        {%- else -%}
+          two
+      {%- endcase -%}
+    LIQUID
+    assigns = { 'foo' => { 'bar' => 'baz' } }
+
+    with_error_modes(:lax, :strict) do
+      assert_template_result("one", template, assigns)
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
+
+  def test_case_when_with_invalid_expression
+    template = <<~LIQUID
+      {%- case 'baz' -%}
+        {%- when foo=>bar -%}
+          one
+        {%- else -%}
+          two
+      {%- endcase -%}
+    LIQUID
+    assigns = { 'foo' => { 'bar' => 'baz' } }
+
+    with_error_modes(:lax, :strict) do
+      assert_template_result("one", template, assigns)
+    end
+
+    with_error_modes(:strict2) do
+      error = assert_raises(Liquid::SyntaxError) { Template.parse(template) }
+
+      assert_match(/Unexpected character =/, error.message)
+    end
+  end
 end

test/unit/tags/doc_tag_unit_test.rb

@@ -20,6 +20,21 @@ class DocTagUnitTest < Minitest::Test
     assert_template_result('', template)
   end
 
+  def test_doc_tag_body_content
+    doc_content = "  Documentation content\n  @param {string} foo - test\n"
+    template_source = "{% doc %}#{doc_content}{% enddoc %}"
+
+    doc_tag = nil
+    ParseTreeVisitor
+      .for(Template.parse(template_source).root)
+      .add_callback_for(Liquid::Doc) do |tag|
+        doc_tag = tag
+      end
+      .visit
+
+    assert_equal(doc_content, doc_tag.nodelist.first.to_s)
+  end
+
   def test_doc_tag_does_not_support_extra_arguments
     error = assert_raises(Liquid::SyntaxError) do
       template = <<~LIQUID.chomp
@@ -116,6 +131,20 @@ class DocTagUnitTest < Minitest::Test
     assert_template_result('', template)
   end
 
+  def test_doc_tag_captures_token_before_enddoc
+    template_source = "{% doc %}{{ incomplete{% enddoc %}"
+
+    doc_tag = nil
+    ParseTreeVisitor
+      .for(Template.parse(template_source).root)
+      .add_callback_for(Liquid::Doc) do |tag|
+        doc_tag = tag
+      end
+      .visit
+
+    assert_equal("{{ incomplete", doc_tag.nodelist.first.to_s)
+  end
+
   def test_doc_tag_preserves_error_line_numbers
     template = Liquid::Template.parse(<<~LIQUID.chomp, line_numbers: true)
       {% doc %}
@@ -145,11 +174,11 @@ class DocTagUnitTest < Minitest::Test
 
   def test_doc_tag_delimiter_handling
     assert_template_result('', <<~LIQUID.chomp)
-      {% if true %}
-        {% doc %}
-          {% docEXTRA %}wut{% enddocEXTRA %}xyz
-        {% enddoc %}
-      {% endif %}
+      {%- if true -%}
+        {%- doc -%}
+          {%- docEXTRA -%}wut{% enddocEXTRA -%}xyz
+        {%- enddoc -%}
+      {%- endif -%}
     LIQUID
 
     assert_template_result('', "{% doc %}123{% enddoc xyz %}")
@@ -167,6 +196,80 @@ class DocTagUnitTest < Minitest::Test
     )
   end
 
+  def test_doc_tag_blank_with_empty_content
+    template_source = "{% doc %}{% enddoc %}"
+
+    doc_tag = nil
+    ParseTreeVisitor
+      .for(Template.parse(template_source).root)
+      .add_callback_for(Liquid::Doc) do |tag|
+        doc_tag = tag
+      end
+      .visit
+
+    assert_equal(true, doc_tag.blank?)
+  end
+
+  def test_doc_tag_blank_with_content
+    template_source = "{% doc %}Some documentation{% enddoc %}"
+
+    doc_tag = nil
+    ParseTreeVisitor
+      .for(Template.parse(template_source).root)
+      .add_callback_for(Liquid::Doc) do |tag|
+        doc_tag = tag
+      end
+      .visit
+
+    assert_equal(false, doc_tag.blank?)
+  end
+
+  def test_doc_tag_blank_with_whitespace_only
+    template_source = "{% doc %}    {% enddoc %}"
+
+    doc_tag = nil
+    ParseTreeVisitor
+      .for(Template.parse(template_source).root)
+      .add_callback_for(Liquid::Doc) do |tag|
+        doc_tag = tag
+      end
+      .visit
+
+    assert_equal(false, doc_tag.blank?)
+  end
+
+  def test_doc_tag_nodelist_returns_array_with_body
+    doc_content = "Documentation content\n@param {string} foo"
+    template_source = "{% doc %}#{doc_content}{% enddoc %}"
+
+    doc_tag = nil
+    ParseTreeVisitor
+      .for(Template.parse(template_source).root)
+      .add_callback_for(Liquid::Doc) do |tag|
+        doc_tag = tag
+      end
+      .visit
+
+    assert_equal([doc_content], doc_tag.nodelist)
+    assert_equal(1, doc_tag.nodelist.length)
+    assert_equal(doc_content, doc_tag.nodelist.first)
+  end
+
+  def test_doc_tag_nodelist_with_empty_content
+    template_source = "{% doc %}{% enddoc %}"
+
+    doc_tag = nil
+    ParseTreeVisitor
+      .for(Template.parse(template_source).root)
+      .add_callback_for(Liquid::Doc) do |tag|
+        doc_tag = tag
+      end
+      .visit
+
+    assert_equal([""], doc_tag.nodelist)
+    assert_equal(1, doc_tag.nodelist.length)
+  end
+
   private
 
   def traversal(template)

test/unit/variable_unit_test.rb

@@ -108,7 +108,7 @@ class VariableUnitTest < Minitest::Test
     assert_equal(VariableLookup.new('foo-bar'), create_variable('foo-bar').name)
     assert_equal(VariableLookup.new('foo-bar-2'), create_variable('foo-bar-2').name)
 
-    with_error_mode(:strict) do
+    with_error_modes(:strict) do
       assert_raises(Liquid::SyntaxError) { create_variable('foo - bar') }
       assert_raises(Liquid::SyntaxError) { create_variable('-foo') }
       assert_raises(Liquid::SyntaxError) { create_variable('2foo') }
@@ -135,16 +135,68 @@ class VariableUnitTest < Minitest::Test
     var = create_variable(%( number_of_comments | pluralize: 'comment': 'comments' ), error_mode: :lax)
     assert_equal(VariableLookup.new('number_of_comments'), var.name)
     assert_equal([['pluralize', ['comment', 'comments']]], var.filters)
+
+    # missing does not throws error
+    create_variable(%(n | f1: ,), error_mode: :lax)
+    create_variable(%(n | f1: ,| f2), error_mode: :lax)
+
+    # arg does not require colon, but ignores args :O, also ignores first kwarg since it splits on ':'
+    var = create_variable(%(n | f1 1 | f2 k1: v1), error_mode: :lax)
+    assert_equal([['f1', []], ['f2', [VariableLookup.new('v1')]]], var.filters)
+
+    # positional and kwargs parsing
+    var = create_variable(%(n | filter: 1, 2, 3 | filter2: k1: 1, k2: 2), error_mode: :lax)
+    assert_equal([['filter', [1, 2, 3]], ['filter2', [], { "k1" => 1, "k2" => 2 }]], var.filters)
+
+    # positional and kwargs intermixed (pos1, key1: val1, pos2)
+    var = create_variable(%(n | link_to: class: "black", "https://example.com", title: "title"), error_mode: :lax)
+    assert_equal([['link_to', ["https://example.com"], { "class" => "black", "title" => "title" }]], var.filters)
   end
 
   def test_strict_filter_argument_parsing
-    with_error_mode(:strict) do
+    with_error_modes(:strict) do
       assert_raises(SyntaxError) do
         create_variable(%( number_of_comments | pluralize: 'comment': 'comments' ))
       end
     end
   end
 
+  def test_strict2_filter_argument_parsing
+    with_error_modes(:strict2) do
+      # optional colon
+      var = create_variable(%(n | f1 | f2:))
+      assert_equal([['f1', []], ['f2', []]], var.filters)
+
+      # missing argument throws error
+      assert_raises(SyntaxError) { create_variable(%(n | f1: ,)) }
+      assert_raises(SyntaxError) { create_variable(%(n | f1: ,| f2)) }
+
+      # arg requires colon
+      assert_raises(SyntaxError) { create_variable(%(n | f1 1)) }
+
+      # trailing comma doesn't throw
+      create_variable(%(n | f1: 1, 2, 3, | f2:))
+
+      # missing comma throws error
+      assert_raises(SyntaxError) { create_variable(%(n | filter: 1 2, 3)) }
+
+      # positional and kwargs parsing
+      var = create_variable(%(n | filter: 1, 2, 3 | filter2: k1: 1, k2: 2))
+      assert_equal([['filter', [1, 2, 3]], ['filter2', [], { "k1" => 1, "k2" => 2 }]], var.filters)
+
+      # positional and kwargs mixed
+      var = create_variable(%(n | filter: 'a', 'b', key1: 1, key2: 2, 'c'))
+      assert_equal([["filter", ["a", "b", "c"], { "key1" => 1, "key2" => 2 }]], var.filters)
+
+      # positional and kwargs intermixed (pos1, key1: val1, pos2)
+      var = create_variable(%(n | link_to: class: "black", "https://example.com", title: "title"))
+      assert_equal([['link_to', ["https://example.com"], { "class" => "black", "title" => "title" }]], var.filters)
+
+      # string key throws
+      assert_raises(SyntaxError) { create_variable(%(n | pluralize: 'comment': 'comments')) }
+    end
+  end
+
   def test_output_raw_source_of_variable
     var = create_variable(%( name_of_variable | upcase ))
     assert_equal(" name_of_variable | upcase ", var.raw)