Engine: Add helpers to compare compiled/rendered outputs of the Engine

.rubocop.yml

@@ -12,6 +12,12 @@ Style/StringLiterals:
   Enabled: true
   EnforcedStyle: double_quotes
 
+Style/MixinUsage:
+  Exclude:
+    - bin/compare
+    - bin/compare-render
+    - bin/compare-compile
+
 Style/ClassAndModuleChildren:
   Enabled: false
 
@@ -94,6 +100,7 @@ Metrics/ModuleLength:
   Exclude:
     - test/**/*.rb
     - templates/**/*.rb
+    - bin/lib/compare_helpers.rb
 
 Metrics/BlockLength:
   Max: 30
@@ -160,6 +167,8 @@ Security/Eval:
     - lib/herb/cli.rb
     - test/**/*.rb
     - bin/erubi-render
+    - bin/compare-render
+    - bin/compare-render
 
 Security/MarshalLoad:
   Exclude:

Gemfile

@@ -7,6 +7,8 @@ gemspec
 gem "prism", github: "ruby/prism", tag: "v1.6.0"
 
 gem "actionview", "~> 8.0"
+gem "difftastic", "~> 0.7"
+gem "erubi"
 gem "lz_string"
 gem "maxitest"
 gem "minitest-difftastic", "~> 0.2"

Gemfile.lock

@@ -183,6 +183,8 @@ PLATFORMS
 
 DEPENDENCIES
   actionview (~> 8.0)
+  difftastic (~> 0.7)
+  erubi
   herb!
   lz_string
   maxitest

bin/compare

@@ -0,0 +1,100 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "pathname"
+require "optparse"
+
+require_relative "lib/compare_helpers"
+
+include CompareHelpers
+
+def usage
+  puts "Usage: #{$PROGRAM_NAME} [options] <file>"
+  puts ""
+  puts "Compares an ERB template with both Herb and Erubi (compile and render)."
+  puts ""
+  puts "Options:"
+  puts "  --no-escape              Disable HTML escaping"
+  puts "  --escape                 Enable HTML escaping (default: false)"
+  puts "  -h, --help               Show this help message"
+  exit(1)
+end
+
+options = {}
+options[:escape] = false
+
+OptionParser.new do |opts|
+  opts.banner = "Usage: #{$PROGRAM_NAME} [options] <file>"
+
+  opts.on("--no-escape", "Disable HTML escaping") do
+    options[:escape] = false
+  end
+
+  opts.on("--escape", "Enable HTML escaping") do
+    options[:escape] = true
+  end
+
+  opts.on("-h", "--help", "Show this help message") do
+    usage
+  end
+end.parse!
+
+file_path = ARGV[0]
+
+unless file_path
+  puts "Error: No file specified"
+  usage
+end
+
+unless File.exist?(file_path)
+  puts "Error: File '#{file_path}' not found"
+  exit(1)
+end
+
+bin_dir = File.expand_path(__dir__)
+
+template = File.read(file_path)
+show_template(file_path, template)
+
+args = []
+args << "--escape" if options[:escape]
+args << "--no-escape" unless options[:escape]
+args << "--no-template"
+args << file_path
+
+box_header("Compiled HTML+ERB Template Output")
+puts ""
+
+compile_result = system(File.join(bin_dir, "compare-compile"), *args)
+
+puts ""
+box_header("Rendered HTML+ERB Template Output")
+puts ""
+
+render_result = system(File.join(bin_dir, "compare-render"), *args)
+
+puts ""
+box_header("Summary")
+
+if render_result && compile_result
+  puts "✓ All comparisons passed!"
+  puts ""
+  puts "  • Rendered outputs match"
+  puts "  • Compiled sources match"
+  exit(0)
+elsif render_result
+  puts "⚠ Rendered outputs match, but compiled sources differ"
+  puts ""
+  puts "  • ✓ Rendered outputs match (what matters!)"
+  puts "  • ✗ Compiled sources differ (different formatting is OK)"
+  puts ""
+  puts "This is usually fine. Herb and Erubi format generated code differently,"
+  puts "but produce the same final output."
+  exit(0)
+else
+  puts "✗ Comparisons failed"
+  puts ""
+  puts "  • Rendered output: #{render_result ? "✓ Match" : "✗ Differ"}"
+  puts "  • Compiled source: #{compile_result ? "✓ Match" : "✗ Differ"}"
+  exit(1)
+end

bin/compare-compile

@@ -0,0 +1,89 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "pathname"
+require "optparse"
+require_relative "lib/compare_helpers"
+
+include CompareHelpers
+
+def usage
+  puts "Usage: #{$PROGRAM_NAME} [options] <file>"
+  puts ""
+  puts "Compiles an ERB template with both Erubi::Engine and Herb::Engine and shows the diff."
+  puts ""
+  puts "Options:"
+  puts "  --no-escape              Disable HTML escaping"
+  puts "  --escape                 Enable HTML escaping (default: false)"
+  puts "  -h, --help               Show this help message"
+  exit(1)
+end
+
+options = {}
+options[:escape] = false
+
+OptionParser.new do |opts|
+  opts.banner = "Usage: #{$PROGRAM_NAME} [options] <file>"
+  parse_common_options(opts, options) { usage }
+end.parse!
+
+options[:show_template] = true unless options.key?(:show_template)
+
+file_path = ARGV[0]
+
+unless file_path
+  puts "Error: No file specified"
+  usage
+end
+
+unless File.exist?(file_path)
+  puts "Error: File '#{file_path}' not found"
+  exit(1)
+end
+
+load_dependencies
+
+template = File.read(file_path)
+show_template(file_path, template) if options[:show_template]
+
+begin
+  herb_engine = Herb::Engine.new(template, options)
+  herb_src = herb_engine.src
+rescue StandardError => e
+  puts "Herb compile error: #{e.message}"
+  exit(1)
+end
+
+begin
+  erubi_engine = Erubi::Engine.new(template, options)
+  erubi_src = erubi_engine.src
+rescue StandardError => e
+  puts "Erubi compile error: #{e.message}"
+  exit(1)
+end
+
+herb_normalized = herb_src.gsub("__herb", "__engine")
+erubi_normalized = erubi_src.gsub("__erubi", "__engine")
+
+if herb_normalized == erubi_normalized
+  puts "✓ Compiled sources match (after normalization)!"
+  puts ""
+  puts "Herb output:"
+  puts herb_src
+  exit(0)
+elsif herb_src == erubi_src
+  puts "✓ Compiled sources match exactly!"
+  puts ""
+  puts "Output:"
+  puts herb_src
+  exit(0)
+else
+  puts "✗ Compiled sources differ!"
+  puts ""
+  puts ""
+
+  diff_output = diff_compiled_sources(erubi_src, herb_src)
+  puts diff_output if diff_output
+
+  exit(1)
+end

bin/compare-render

@@ -0,0 +1,80 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+require "pathname"
+require "optparse"
+require_relative "lib/compare_helpers"
+
+include CompareHelpers
+
+def usage
+  puts "Usage: #{$PROGRAM_NAME} [options] <file>"
+  puts ""
+  puts "Renders an ERB template with both Erubi::Engine and Herb::Engine and shows the diff."
+  puts ""
+  puts "Options:"
+  puts "  --no-escape              Disable HTML escaping"
+  puts "  --escape                 Enable HTML escaping (default: false)"
+  puts "  -h, --help               Show this help message"
+  exit(1)
+end
+
+options = {}
+options[:escape] = false
+
+OptionParser.new do |opts|
+  opts.banner = "Usage: #{$PROGRAM_NAME} [options] <file>"
+  parse_common_options(opts, options) { usage }
+end.parse!
+
+options[:show_template] = true unless options.key?(:show_template)
+
+file_path = ARGV[0]
+
+unless file_path
+  puts "Error: No file specified"
+  usage
+end
+
+unless File.exist?(file_path)
+  puts "Error: File '#{file_path}' not found"
+  exit(1)
+end
+
+load_dependencies
+
+template = File.read(file_path)
+show_template(file_path, template) if options[:show_template]
+
+begin
+  herb_engine = Herb::Engine.new(template, options)
+  herb_output = eval(herb_engine.src)
+rescue StandardError => e
+  puts "Herb render error: #{e.message}"
+  exit(1)
+end
+
+begin
+  erubi_engine = Erubi::Engine.new(template, options)
+  erubi_output = eval(erubi_engine.src)
+rescue StandardError => e
+  puts "Erubi render error: #{e.message}"
+  exit(1)
+end
+
+if herb_output == erubi_output
+  puts "✓ Outputs match!"
+  puts ""
+  puts "Output:"
+  puts herb_output
+  exit(0)
+else
+  puts "✗ Outputs differ!"
+  puts ""
+  puts ""
+
+  diff_output = diff_rendered_outputs(erubi_output, herb_output)
+  puts diff_output if diff_output
+
+  exit(1)
+end