Change incremental to perform an additional AST dirtyness check

* This avoids situations where no semantic change occured to trigger incremental selection.

lib/mutant.rb

@@ -246,6 +246,7 @@ module Mutant
  require 'mutant/repository'
  require 'mutant/repository/diff'
  require 'mutant/repository/diff/ranges'
+ require 'mutant/repository/file_revision'
  require 'mutant/zombifier'
  require 'mutant/range'
  require 'mutant/license'
@@ -319,6 +320,7 @@ module Mutant
  mutex: Mutex,
  object_space: ObjectSpace,
  open3: Open3,
+ parser: Parser.new,
  pathname: Pathname,
  process: Process,
  random: Random,

lib/mutant/cli/command/environment.rb

@@ -102,11 +102,13 @@ def add_matcher_options(parser)
  parser.on('--start-subject EXPRESSION', 'Start mutation testing at a specific subject') do |pattern|
  add_matcher(:start_expressions, @config.expression_parser.call(pattern).from_right)
  end
- parser.on('--since REVISION', 'Only select subjects touched since REVISION') do |revision|
+ parser.on('--since REVISION', 'Only select dirty subjects since REVISION') do |revision|
  add_matcher(
  :subject_filters,
  Repository::SubjectFilter.new(
- Repository::Diff.new(to: revision, world: world)
+ diff: Repository::Diff.new(to: revision, world: world),
+ revision: revision,
+ world: world
  )
  )
  end

lib/mutant/env.rb

@@ -9,7 +9,6 @@ class Env
  :integration,
  :matchable_scopes,
  :mutations,
- :parser,
  :selector,
  :subjects,
  :world
@@ -37,7 +36,6 @@ def self.empty(world, config)
  ),
  matchable_scopes: EMPTY_ARRAY,
  mutations: EMPTY_ARRAY,
- parser: Parser.new,
  selector: Selector::Null.new,
  subjects: EMPTY_ARRAY,
  world: world
@@ -64,6 +62,13 @@ def cover_index(mutation_index)
  )
  end
 
+ # The parser
+ #
+ # @return [Parser]
+ def parser
+ world.parser
+ end
+
  # The test selections
  #
  # @return Hash{Mutation => Enumerable<Test>}

lib/mutant/repository.rb

@@ -4,7 +4,7 @@ module Mutant
  module Repository
  # Subject filter based on repository diff
  class SubjectFilter
- include Adamantium, Concord.new(:diff)
+ include Adamantium, Anima.new(:diff, :revision, :world)
 
  # Test if subject was touched in diff
  #

lib/mutant/repository/file_revision.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module Mutant
+ module Repository
+ class FileRevision
+ def self.read(world:, revision:, file_name:)
+ world
+ .capture_stdout(%w[git show #{revision}:#{file_name}])
+ end
+ end # FileRevision
+ end # Repository
+end # Mutant

lib/mutant/world.rb

@@ -16,6 +16,7 @@ class World
  :mutex,
  :object_space,
  :open3,
+ :parser,
  :pathname,
  :process,
  :random,

spec/spec_helper.rb

@@ -114,6 +114,7 @@ def fake_world
  mutex: class_double(Mutex),
  object_space: class_double(ObjectSpace),
  open3: class_double(Open3),
+ parser: class_double(Mutant::Parser),
  pathname: class_double(Pathname),
  process: class_double(Process),
  random: class_double(Random),

spec/unit/mutant/bootstrap_spec.rb

@@ -56,6 +56,7 @@ def require(_); end
  kernel: kernel,
  load_path: load_path,
  object_space: object_space,
+ parser: Mutant::Parser.new,
  pathname: Pathname,
  recorder: instance_double(Mutant::Segment::Recorder),
  timer: timer

spec/unit/mutant/cli_spec.rb

@@ -301,7 +301,7 @@ def self.main_body
  Matcher:
  --ignore-subject EXPRESSION Ignore subjects that match EXPRESSION as prefix
  --start-subject EXPRESSION Start mutation testing at a specific subject
- --since REVISION Only select subjects touched since REVISION
+ --since REVISION Only select dirty subjects since REVISION
  MESSAGE
 
  {
@@ -348,7 +348,7 @@ def self.main_body
  Matcher:
  --ignore-subject EXPRESSION Ignore subjects that match EXPRESSION as prefix
  --start-subject EXPRESSION Start mutation testing at a specific subject
- --since REVISION Only select subjects touched since REVISION
+ --since REVISION Only select dirty subjects since REVISION
  MESSAGE
 
  {
@@ -395,7 +395,7 @@ def self.main_body
  Matcher:
  --ignore-subject EXPRESSION Ignore subjects that match EXPRESSION as prefix
  --start-subject EXPRESSION Start mutation testing at a specific subject
- --since REVISION Only select subjects touched since REVISION
+ --since REVISION Only select dirty subjects since REVISION
  MESSAGE
 
  {
@@ -1290,10 +1290,12 @@ def self.main_body
  matcher: file_config.matcher.with(
  subject_filters: [
  Mutant::Repository::SubjectFilter.new(
- Mutant::Repository::Diff.new(
+ diff: Mutant::Repository::Diff.new(
  to: 'reference',
  world: world
- )
+ ),
+ revision: 'reference',
+ world: world
  )
  ]
  )
@@ -1305,10 +1307,12 @@ def self.main_body
  matcher: file_config.matcher.with(
  subject_filters: [
  Mutant::Repository::SubjectFilter.new(
- Mutant::Repository::Diff.new(
+ diff: Mutant::Repository::Diff.new(
  to: 'reference',
  world: world
- )
+ ),
+ revision: 'reference',
+ world: world
  )
  ]
  )

spec/unit/mutant/env_spec.rb

@@ -8,7 +8,6 @@
  integration: integration,
  matchable_scopes: [],
  mutations: [mutation],
- parser: Mutant::Parser.new,
  selector: selector,
  subjects: subjects,
  world: world
@@ -239,7 +238,6 @@ def apply
  integration: integration,
  matchable_scopes: Mutant::EMPTY_ARRAY,
  mutations: Mutant::EMPTY_ARRAY,
- parser: Mutant::Parser.new,
  selector: Mutant::Selector::Null.new,
  subjects: Mutant::EMPTY_ARRAY,
  world: world
@@ -268,4 +266,10 @@ def apply
  expect(events).to eql([%i[test_segment value]])
  end
  end
+
+ describe '#parser' do
+ it 'returns the world parser' do
+ expect(subject.parser).to be(world.parser)
+ end
+ end
 end

spec/unit/mutant/repository/subject_filter_spec.rb

@@ -2,11 +2,19 @@
 
 RSpec.describe Mutant::Repository::SubjectFilter do
  context '#call' do
- subject { object.call(mutant_subject) }
+ def apply
+ subject.call(mutant_subject)
+ end
 
- let(:object) { described_class.new(diff) }
- let(:diff) { instance_double(Mutant::Repository::Diff) }
- let(:value) { instance_double(Object, 'value') }
+ subject do
+ described_class.new(
+ diff: diff,
+ revision: 'revision',
+ world: fake_world
+ )
+ end
+
+ let(:diff) { instance_double(Mutant::Repository::Diff) }
 
  let(:mutant_subject) do
  double(
@@ -20,11 +28,15 @@
  expect(diff).to receive(:touches?).with(
  mutant_subject.source_path,
  mutant_subject.source_lines
- ).and_return(value)
+ ).and_return(touches?)
  end
 
- it 'connects return value to repository diff API' do
- expect(subject).to be(value)
+ context 'when subject lines are not touched' do
+ let(:touches?) { false }
+
+ it 'returns false' do
+ expect(apply).to be(false)
+ end
  end
  end
 end