Change required Ruby version to >=2.3

* This commit does every 2.3 change required to get the build pass
* None of the changes can be extracted, without changing the build setup

.rubocop.yml

@@ -4,4 +4,4 @@ AllCops:
     - 'test_app/**/*'
     - 'tmp/**/*'
     - 'vendor/**/*'
-  TargetRubyVersion: 2.2
+  TargetRubyVersion: 2.3

Changelog.md

@@ -1,3 +1,8 @@
+# v0.8.17 2018-09-12
+
+* Drop support for Ruby < 2.3
+* Use frozen string literals globally
+
 # v0.8.16 2018-08-03
 
 * Support for rspec-3.x

Gemfile

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 source 'https://rubygems.org'
 
 gemspec name: 'mutant'

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    mutant (0.8.14)
+    mutant (0.8.16)
       abstract_type (~> 0.0.7)
       adamantium (~> 0.2.0)
       anima (~> 0.3.0)
@@ -17,9 +17,9 @@ PATH
       procto (~> 0.0.2)
       regexp_parser (~> 0.4.9)
       unparser (~> 0.2.5)
-    mutant-rspec (0.8.14)
-      mutant (~> 0.8.14)
-      rspec-core (>= 3.4.0, < 3.8.0)
+    mutant-rspec (0.8.16)
+      mutant (~> 0.8.16)
+      rspec-core (>= 3.4.0, < 4.0.0)
 
 GEM
   remote: https://rubygems.org/
@@ -105,7 +105,7 @@ GEM
       codeclimate-engine-rb (~> 0.4.0)
       parser (>= 2.4.0.0, < 2.5)
       rainbow (~> 2.0)
-    regexp_parser (0.4.9)
+    regexp_parser (0.4.13)
     rspec (3.5.0)
       rspec-core (~> 3.5.0)
       rspec-expectations (~> 3.5.0)
@@ -139,13 +139,13 @@ GEM
     simplecov-html (0.10.1)
     thread_safe (0.3.6)
     unicode-display_width (1.3.0)
-    unparser (0.2.6)
+    unparser (0.2.8)
       abstract_type (~> 0.0.7)
       adamantium (~> 0.2.0)
       concord (~> 0.1.5)
       diff-lcs (~> 1.3)
       equalizer (~> 0.0.9)
-      parser (>= 2.3.1.2, < 2.5)
+      parser (>= 2.3.1.2, < 2.6)
       procto (~> 0.0.2)
     virtus (1.0.5)
       axiom-types (~> 0.1)
@@ -166,4 +166,4 @@ DEPENDENCIES
   mutant!
 
 BUNDLED WITH
-   1.15.4
+   1.16.4

Rakefile

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'devtools'
 
 Devtools.init_rake_tasks

bin/mutant

@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
 trap('INT') do |status|
   effective_status = status ? status + 128 : 128

config/flay.yml

@@ -1,3 +1,3 @@
 ---
 threshold: 16
-total_score: 1316
+total_score: 1318

lib/mutant.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'abstract_type'
 require 'adamantium'
 require 'anima'

lib/mutant/actor.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # A minimal actor implementation
   module Actor

lib/mutant/actor/env.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module Actor
     # Actor root environment

lib/mutant/actor/mailbox.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module Actor
     # Unbound mailbox

lib/mutant/actor/receiver.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module Actor
     # Receiver side of an actor

lib/mutant/actor/sender.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module Actor
 

lib/mutant/ast.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # AST helpers
   module AST

lib/mutant/ast/meta.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Node meta information mixin

lib/mutant/ast/meta/const.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Node meta information mixin

lib/mutant/ast/meta/optarg.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Node meta information mixin

lib/mutant/ast/meta/resbody.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Node meta information mixin

lib/mutant/ast/meta/restarg.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Node meta information mixin

lib/mutant/ast/meta/send.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Node meta information mixin

lib/mutant/ast/meta/symbol.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Node meta information mixin

lib/mutant/ast/named_children.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
 

lib/mutant/ast/node_predicates.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Module for node predicates

lib/mutant/ast/nodes.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Singleton nodes

lib/mutant/ast/regexp.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Regexp source mapper

lib/mutant/ast/regexp/transformer.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp

lib/mutant/ast/regexp/transformer/alternative.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp

lib/mutant/ast/regexp/transformer/character_set.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp

lib/mutant/ast/regexp/transformer/direct.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp

lib/mutant/ast/regexp/transformer/options_group.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp

lib/mutant/ast/regexp/transformer/quantifier.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp
@@ -99,7 +100,7 @@ def quantifier
             #
             # @return [String]
             def interval_text
-              interval = [min, max].map { |num| num if num > 0 }.uniq
+              interval = [min, max].map { |num| num if num.positive? }.uniq
               "{#{interval.join(',')}}"
             end
           end # ASTToExpression

lib/mutant/ast/regexp/transformer/recursive.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp

lib/mutant/ast/regexp/transformer/root.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp

lib/mutant/ast/regexp/transformer/text.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     module Regexp

lib/mutant/ast/sexp.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Mixin for node sexp syntax

lib/mutant/ast/types.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   module AST
     # Groups of node types

lib/mutant/cli.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # Commandline parser / runner
   class CLI

lib/mutant/color.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # Class to colorize strings
   class Color

lib/mutant/config.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # Standalone configuration of a mutant execution.
   #

lib/mutant/context.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # An abstract context where mutations can be applied to.
   class Context

lib/mutant/diff.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # Class to create diffs from source code
   class Diff
@@ -17,7 +18,7 @@ class Diff
     def diff
       return if diffs.empty?
 
-      minimized_hunk.diff(:unified) << NEWLINE
+      minimized_hunk.diff(:unified) + NEWLINE
     end
     memoize :diff
 
@@ -68,7 +69,7 @@ def diffs
     # @return [Array<Diff::LCS::Hunk>]
     def hunks
       diffs.map do |diff|
-        ::Diff::LCS::Hunk.new(old, new, diff, max_length, 0)
+        ::Diff::LCS::Hunk.new(old.map(&:dup), new, diff, max_length, 0)
       end
     end
 

lib/mutant/env.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # Abstract base class for mutant environments
   class Env

lib/mutant/env/bootstrap.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Env
     # Bootstrap environment

lib/mutant/expression.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
 
   # Abstract base class for match expression

lib/mutant/expression/method.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Expression
 

lib/mutant/expression/methods.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Expression
 

lib/mutant/expression/namespace.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Expression
     # Abstract base class for expressions matching namespaces

lib/mutant/expression/parser.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Expression
     class Parser

lib/mutant/integration.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
 
   # Abstract base class mutant test framework integrations

lib/mutant/integration/rspec.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require 'rspec/core'
 
 module Mutant

lib/mutant/isolation.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Isolation
     include AbstractType

lib/mutant/isolation/fork.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Isolation
     # Isolation via the fork(2) systemcall.

lib/mutant/isolation/none.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # Module providing isolation
   class Isolation

lib/mutant/loader.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # Base class for code loaders
   class Loader

lib/mutant/matcher.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   # Abstract matcher to find subjects to mutate
   class Matcher

lib/mutant/matcher/chain.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Matcher
     # Matcher chaining results of other matchers together

lib/mutant/matcher/compiler.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Matcher
 

lib/mutant/matcher/config.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Matcher
     # Subject matcher configuration

lib/mutant/matcher/filter.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Matcher
     # Matcher filter

lib/mutant/matcher/method.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Matcher
     # Abstract base class for method matchers

lib/mutant/matcher/method/instance.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Matcher
     class Method

lib/mutant/matcher/method/singleton.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Matcher
     class Method

lib/mutant/matcher/methods.rb

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Mutant
   class Matcher
     # Abstract base class for matcher that returns method subjects from scope