Frozen string literal changes (#967)

* Frozen string

* Revert changes that are slower

* Add object to map conversion for temple engine

* Revert more frozen strings

* Get rid of unnecessary extra array

* Revert this change because it's slower in benchmarks

* parser

* true for filters

* compiler

* temple

* finalize

lib/haml/compiler.rb

@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'haml/attribute_builder'
 require 'haml/attribute_compiler'
 require 'haml/temple_line_counter'
@@ -315,7 +315,7 @@ def rstrip_buffer!(index = -1)
 
       case last.first
       when :text
-        last[1].rstrip!
+        last[1] = last[1].rstrip
         if last[1].empty?
           @to_merge.slice! index
           rstrip_buffer! index

lib/haml/engine.rb

@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'forwardable'
 
 require 'haml/parser'
@@ -166,8 +166,13 @@ def render_proc(scope = Object.new, *local_names)
       end
 
       begin
-        eval("Proc.new { |*_haml_locals| _haml_locals = _haml_locals[0] || {};" <<
-             @temple_engine.precompiled_with_ambles(local_names) << "}\n", scope, @options.filename, @options.line)
+        str = @temple_engine.precompiled_with_ambles(local_names)
+        eval(
+          "Proc.new { |*_haml_locals| _haml_locals = _haml_locals[0] || {}; #{str}}\n",
+          scope,
+          @options.filename,
+          @options.line
+        )
       rescue ::SyntaxError => e
         raise SyntaxError, e.message
       end

lib/haml/filters.rb

@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require "tilt"
 
 module Haml
@@ -183,8 +183,7 @@ def compile(compiler, text)
           end
 
           rendered = Haml::Helpers::find_and_preserve(filter.render_with_options(text, compiler.options), compiler.options[:preserve])
-          rendered.rstrip!
-          push_text("#{rendered}\n")
+          push_text("#{rendered.rstrip}\n")
         end
       end
     end
@@ -247,10 +246,7 @@ module Cdata
 
       # @see Base#render
       def render(text)
-        text = "\n#{text}"
-        text.rstrip!
-        text.gsub!("\n", "\n    ")
-        "<![CDATA[#{text}\n]]>"
+        "<![CDATA[#{"\n#{text.rstrip}".gsub("\n", "\n    ")}\n]]>"
       end
     end
 

lib/haml/generator.rb

@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 module Haml
   # Ruby code generator, which is a limited version of Temple::Generator.
   # Limit methods since Haml doesn't need most of them.

lib/haml/helpers.rb

@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'erb'
 
 module Haml
@@ -109,10 +109,7 @@ def non_haml
     #   @yield The block within which to escape newlines
     def find_and_preserve(input = nil, tags = haml_buffer.options[:preserve], &block)
       return find_and_preserve(capture_haml(&block), input || tags) if block
-      tags = tags.each_with_object('') do |t, s|
-        s << '|' unless s.empty?
-        s << Regexp.escape(t)
-      end
+      tags = tags.map { |tag| Regexp.escape(tag) }.join('|')
       re = /<(#{tags})([^>]*)>(.*?)(<\/\1>)/im
       input.to_s.gsub(re) do |s|
         s =~ re # Can't rely on $1, etc. existing since Rails' SafeBuffer#gsub is incompatible
@@ -200,8 +197,8 @@ def preserve(input = nil, &block)
     # @yield [item] A block which contains Haml code that goes within list items
     # @yieldparam item An element of `enum`
     def list_of(enum, opts={}, &block)
-      opts_attributes = opts.each_with_object('') {|(k, v), s| s << " #{k}='#{v}'"}
-      enum.each_with_object('') do |i, ret|
+      opts_attributes = opts.map { |k, v| " #{k}='#{v}'" }.join
+      enum.map do |i|
         result = capture_haml(i, &block)
 
         if result.count("\n") > 1
@@ -211,9 +208,8 @@ def list_of(enum, opts={}, &block)
           result.strip!
         end
 
-        ret << "\n" unless ret.empty?
-        ret << %Q!<li#{opts_attributes}>#{result}</li>!
-      end
+        %Q!<li#{opts_attributes}>#{result}</li>!
+      end.join("\n")
     end
 
     # Returns a hash containing default assignments for the `xmlns`, `lang`, and `xml:lang`
@@ -704,4 +700,3 @@ def is_haml?
     false
   end
 end
-

lib/haml/parser.rb

@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'strscan'
 
 module Haml
@@ -698,7 +698,7 @@ def parse_new_attributes(text)
       end
 
       static_attributes = {}
-      dynamic_attributes = "{"
+      dynamic_attributes = "{".dup
       attributes.each do |name, (type, val)|
         if type == :static
           static_attributes[name] = val
@@ -738,7 +738,7 @@ def parse_new_attribute(scanner)
 
       return name, [:static, content.first[1]] if content.size == 1
       return name, [:dynamic,
-        %!"#{content.each_with_object('') {|(t, v), s| s << (t == :str ? inspect_obj(v)[1...-1] : "\#{#{v}}")}}"!]
+        %!"#{content.each_with_object(''.dup) {|(t, v), s| s << (t == :str ? inspect_obj(v)[1...-1] : "\#{#{v}}")}}"!]
     end
 
     def next_line

lib/haml/temple_engine.rb

@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 require 'temple'
 require 'haml/escapable'
 require 'haml/generator'
@@ -49,7 +49,7 @@ def compile(template)
     # @return [String]
     def precompiled
       encoding = Encoding.find(@encoding || '')
-      return @precompiled.force_encoding(encoding) if encoding == Encoding::ASCII_8BIT
+      return @precompiled.dup.force_encoding(encoding) if encoding == Encoding::ASCII_8BIT
       return @precompiled.encode(encoding)
     end
 
@@ -64,14 +64,14 @@ def precompiled_with_return_value
     #
     # @return [String]
     def precompiled_with_ambles(local_names, after_preamble: '')
-      preamble = <<END.tr!("\n", ';')
+      preamble = <<END.tr("\n", ';')
 begin
 extend Haml::Helpers
 _hamlout = @haml_buffer = Haml::Buffer.new(haml_buffer, #{Options.new(options).for_buffer.inspect})
 _erbout = _hamlout.buffer
 #{after_preamble}
 END
-      postamble = <<END.tr!("\n", ';')
+      postamble = <<END.tr("\n", ';')
 #{precompiled_method_return_value}
 ensure
 @haml_buffer = @haml_buffer.upper if @haml_buffer
@@ -99,12 +99,12 @@ def precompiled_method_return_value
     def locals_code(names)
       names = names.keys if Hash === names
 
-      names.each_with_object('') do |name, code|
+      names.map do |name|
         # Can't use || because someone might explicitly pass in false with a symbol
         sym_local = "_haml_locals[#{inspect_obj(name.to_sym)}]"
         str_local = "_haml_locals[#{inspect_obj(name.to_s)}]"
-        code << "#{name} = #{sym_local}.nil? ? #{str_local} : #{sym_local};"
-      end
+        "#{name} = #{sym_local}.nil? ? #{str_local} : #{sym_local};"
+      end.join
     end
 
     def inspect_obj(obj)

lib/haml/util.rb

@@ -1,4 +1,4 @@
-# frozen_string_literal: false
+# frozen_string_literal: true
 
 begin
   require 'erubis/tiny'
@@ -166,7 +166,7 @@ def handle_interpolation(str)
     #   and the rest of the string.
     #   `["Foo (Bar (Baz bang) bop)", " (Bang (bop bip))"]` in the example above.
     def balance(scanner, start, finish, count = 0)
-      str = ''
+      str = ''.dup
       scanner = StringScanner.new(scanner) unless scanner.is_a? StringScanner
       regexp = Regexp.new("(.*?)[\\#{start.chr}\\#{finish.chr}]", Regexp::MULTILINE)
       while scanner.scan(regexp)
@@ -199,7 +199,7 @@ def contains_interpolation?(str)
     end
 
     def unescape_interpolation(str, escape_html = nil)
-      res = ''
+      res = ''.dup
       rest = Haml::Util.handle_interpolation str.dump do |scan|
         escapes = (scan[2].size - 1) / 2
         char = scan[3] # '{', '@' or '$'

test/attribute_parser_test.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'test_helper'
 
 class AttributeParserTeset < Haml::TestCase

test/filters_test.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'test_helper'
 
 class FiltersTest < Haml::TestCase

test/helper_test.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'test_helper'
 require "active_model/naming"
 

test/options_test.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'test_helper'
 
 module Haml

test/parser_test.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'test_helper'
 
 module Haml
@@ -66,7 +67,7 @@ class ParserTest < Haml::TestCase
         flunk 'else clause after if containing unless should be accepted'
       end
     end
-    
+
     test "loud script with else is accepted" do
       begin
         parse "= if true\n  - 'A'\n-else\n  - 'B'"

test/template_test_helper.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module TemplateTestHelper
   TEMPLATE_PATH = File.join(__dir__, "templates")
 end

test/temple_line_counter_test.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'test_helper'
 
 class TempleLineCounterTest < Haml::TestCase

test/util_test.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'test_helper'
 
 class UtilTest < Haml::TestCase