Upgrade to unparser 0.7.x interface

Author: mbj

Changelog.md

@@ -1,3 +1,26 @@
+# v0.13.0 unreleased
+
+  Significant unparser upgrade. Mutant now:
+
+  Avoids emitting mutations that do not round trip against unparsers API.
+
+  This change generates less mutations, and currently slightly increases boot time.
+  But the number of mutations that are hitting the test suite is much lower so it
+  should balance.
+
+  Also its a good step towards parallel mutation generation reducing boot times.
+
+  Also mutations that are currently not creating round trippable ASTS are removed:
+
+  * Negation of `if` conditions, as negating these needs operator precendence sensitive AST
+    mutations mutant does not have the infrastructure for right now. The mutation to `unless` is
+    still present so there is no real reduction of semantic coverage.
+
+  * All mutations that modify the local variable scope are removed. These generated ASTs that would
+    not round trip and are thus likely to be covered, execution wise these would move lvar reads to
+    implicit self receivers in the past. But this was not intended by these mutations, at least not
+    without explicitly changing the reads to send nodes explicitly.
+
 # v0.12.5 unreleased
 
 * [#1458](https://github.com/mbj/mutant/pull/1458)

Gemfile.lock

@@ -1,3 +1,10 @@
+PATH
+  remote: ../unparser
+  specs:
+    unparser (0.7.0)
+      diff-lcs (~> 1.3)
+      parser (>= 3.3.0)
+
 PATH
   remote: .
   specs:
@@ -6,60 +13,53 @@ PATH
       parser (~> 3.3.0)
       regexp_parser (~> 2.9.0)
       sorbet-runtime (~> 0.5.0)
-      unparser (~> 0.6.14)
+      unparser (~> 0.7.0)
 
 GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.2)
     diff-lcs (1.5.1)
-    json (2.7.2)
+    json (2.7.5)
     language_server-protocol (3.17.0.3)
-    parallel (1.25.1)
-    parser (3.3.2.0)
+    parallel (1.26.3)
+    parser (3.3.6.0)
       ast (~> 2.4.1)
       racc
-    racc (1.8.0)
+    racc (1.8.1)
     rainbow (3.1.1)
     regexp_parser (2.9.2)
-    rexml (3.2.9)
-      strscan
     rspec (3.13.0)
       rspec-core (~> 3.13.0)
       rspec-expectations (~> 3.13.0)
       rspec-mocks (~> 3.13.0)
-    rspec-core (3.13.0)
+    rspec-core (3.13.2)
       rspec-support (~> 3.13.0)
-    rspec-expectations (3.13.0)
+    rspec-expectations (3.13.3)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
-    rspec-its (1.3.0)
+    rspec-its (1.3.1)
       rspec-core (>= 3.0.0)
       rspec-expectations (>= 3.0.0)
-    rspec-mocks (3.13.1)
+    rspec-mocks (3.13.2)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.13.0)
     rspec-support (3.13.1)
-    rubocop (1.64.1)
+    rubocop (1.67.0)
       json (~> 2.3)
       language_server-protocol (>= 3.17.0)
       parallel (~> 1.10)
       parser (>= 3.3.0.2)
       rainbow (>= 2.2.2, < 4.0)
-      regexp_parser (>= 1.8, < 3.0)
-      rexml (>= 3.2.5, < 4.0)
-      rubocop-ast (>= 1.31.1, < 2.0)
+      regexp_parser (>= 2.4, < 3.0)
+      rubocop-ast (>= 1.32.2, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.31.3)
+    rubocop-ast (1.33.0)
       parser (>= 3.3.1.0)
     ruby-progressbar (1.13.0)
-    sorbet-runtime (0.5.11422)
-    strscan (3.1.0)
-    unicode-display_width (2.5.0)
-    unparser (0.6.14)
-      diff-lcs (~> 1.3)
-      parser (>= 3.3.0)
+    sorbet-runtime (0.5.11625)
+    unicode-display_width (2.6.0)
 
 PLATFORMS
   ruby
@@ -70,6 +70,7 @@ DEPENDENCIES
   rspec-core (~> 3.10)
   rspec-its (~> 1.3.0)
   rubocop (~> 1.7)
+  unparser!
 
 BUNDLED WITH
    2.5.6

Gemfile.shared

@@ -0,0 +1 @@
+gem 'unparser', path: '../unparser'

lib/mutant/cli/command/util.rb

@@ -20,8 +20,11 @@ def action
               end
             end
 
-            @targets.each(&method(:print_mutations))
-            Either::Right.new(nil)
+            if @targets.map(&method(:print_mutations)).all?
+              Either::Right.new(nil)
+            else
+              Either::Left.new('Invalid mutation detected!')
+            end
           end
 
         private
@@ -73,15 +76,24 @@ def add_target_options(parser)
           def print_mutations(target)
             world.stdout.puts(target.identification)
 
+            success = true
+
             Mutator::Node.mutate(
               config: Mutant::Mutation::Config::DEFAULT.with(ignore_patterns: @ignore_patterns),
               node:   target.node
             ).each do |mutation|
-              Reporter::CLI::Printer::Mutation.call(
-                object: Mutant::Mutation::Evil.new(subject: target, node: mutation),
-                output: world.stdout
+              Mutant::Mutation::Evil.from_node(subject: target, node: mutation).either(
+                ->(violation) { world.stdout.puts(violation.report); success = false },
+                ->(object) {
+                  Reporter::CLI::Printer::Mutation.call(
+                    object:,
+                    output: world.stdout
+                  )
+                }
               )
             end
+
+            success
           end
 
           def parse_remaining_arguments(arguments)

lib/mutant/meta/example.rb

@@ -23,7 +23,7 @@ class Expected
       #
       # @return [Verification]
       def verification
-        Verification.new(example: self, mutations: generated)
+        Verification.from_mutations(example: self, mutations: generated)
       end
       memoize :verification
 
@@ -61,7 +61,7 @@ def generated
           config: Mutation::Config::DEFAULT.with(operators:),
           node:
         ).map do |node|
-          Mutation::Evil.new(subject: self, node:)
+          Mutation::Evil.from_node(subject: self, node:)
         end
       end
       memoize :generated

lib/mutant/meta/example/verification.rb

@@ -5,14 +5,24 @@ module Meta
     class Example
       # Example verification
       class Verification
-        include Adamantium, Anima.new(:example, :mutations)
+        include Adamantium, Anima.new(:example, :invalid, :valid)
+
+        def self.from_mutations(example:, mutations:)
+          valid, invalid = [], []
+
+          mutations.each do |mutation|
+            mutation.either(invalid.public_method(:<<), valid.public_method(:<<))
+          end
+
+          new(example:, invalid:, valid:)
+        end
 
         # Test if mutation was verified successfully
         #
         # @return [Boolean]
         def success?
           [
-            original_verification,
+            original_verification_report,
             invalid,
             missing,
             no_diffs,
@@ -29,12 +39,12 @@ def error_report
 
         def reports
           reports = [example.location]
-          reports.concat(original)
-          reports.concat(original_verification)
+          reports.concat(original_report)
+          reports.concat(original_verification_report)
           reports.concat(make_report('Missing mutations:', missing))
           reports.concat(make_report('Unexpected mutations:', unexpected))
           reports.concat(make_report('No-Diff mutations:', no_diffs))
-          reports.concat(invalid)
+          reports.concat(invalid_report)
         end
 
         def make_report(label, mutations)
@@ -52,15 +62,15 @@ def report_mutation(mutation)
           ]
         end
 
-        def original
+        def original_report
           [
             "Original: (operators: #{example.operators.class.operators_name})",
             example.node,
             example.original_source
           ]
         end
 
-        def original_verification
+        def original_verification_report
           validation = Unparser::Validation.from_string(example.original_source)
           if validation.success?
             []
@@ -77,30 +87,34 @@ def prefix(prefix, string)
           end.join
         end
 
-        def invalid
-          mutations.each_with_object([]) do |mutation, aggregate|
-            validation = Unparser::Validation.from_node(mutation.node)
-            aggregate << prefix('[invalid-mutation]', validation.report) unless validation.success?
+        def invalid_report
+          invalid.map do |validation|
+            prefix('[invalid-mutation]', validation.report)
           end
         end
-        memoize :invalid
+        memoize :invalid_report
 
         def unexpected
-          mutations.reject do |mutation|
+          valid.reject do |mutation|
             example.expected.any? { |expected| expected.node.eql?(mutation.node) }
           end
         end
         memoize :unexpected
 
         def missing
-          (example.expected.map(&:node) - mutations.map(&:node)).map do |node|
-            Mutation::Evil.new(subject: example, node:)
+          example.expected.each_with_object([]) do |expected, aggregate|
+            next if valid.any? { |mutation| expected.node.eql?(mutation.node) }
+            aggregate << Mutation::Evil.new(
+              node:    expected.node,
+              source:  expected.original_source,
+              subject: example
+            )
           end
         end
         memoize :missing
 
         def no_diffs
-          mutations.select { |mutation| mutation.source.eql?(example.original_source_generated) }
+          valid.select { |mutation| mutation.source.eql?(example.original_source_generated) }
         end
         memoize :no_diffs
 

lib/mutant/mutation.rb

@@ -4,11 +4,69 @@ module Mutant
   # Represent a mutated node with its subject
   class Mutation
     include AbstractType, Adamantium
-    include Anima.new(:subject, :node)
+    include Anima.new(:subject, :node, :source)
 
     CODE_DELIMITER = "\0"
     CODE_RANGE     = (..4)
 
+    class GenerationError
+      include Anima.new(:subject, :node, :unparser_violation)
+
+      MESSAGE = <<~'MESSAGE'
+        === Mutation-Generation-Error ===
+        This is a mutant internal issue detected by a mutant internal cross check.
+        Please report an issue with the details below.
+
+        Subject: %<subject_identification>s.
+
+        Mutation-Source-Diff:
+        %<mutation_source_diff>s
+
+        Mutation-Node-Diff:
+        %<mutation_node_diff>s
+
+        Unparser-Violation:
+        %<unparser_violation>s
+      MESSAGE
+
+      def report
+        MESSAGE % {
+          mutation_source_diff:,
+          mutation_node_diff:,
+          subject_identification: subject.identification,
+          unparser_violation: unparser_violation.report
+        }
+      end
+
+    private
+
+      def mutation_source_diff
+        mutation = Mutation::Evil.new(
+          subject:,
+          node:,
+          source: unparser_violation.original_source.from_right
+        )
+
+        mutation.diff.colorized_diff
+      end
+
+      def mutation_node_diff
+        Unparser::Diff.new(
+          subject.node.to_s.lines.map(&:chomp),
+          node.to_s.lines.map(&:chomp)
+        ).colorized_diff
+      end
+    end # GenerationError
+
+    def self.from_node(subject:, node:)
+      ast = Unparser::AST.from_node(node:)
+
+      Unparser
+        .unparse_validate_ast_either(ast:)
+        .lmap { |unparser_violation| GenerationError.new(subject:, node:, unparser_violation:) }
+        .fmap { |source| new(node:, source:, subject:) }
+    end
+
     # Mutation identification code
     #
     # @return [String]
@@ -17,14 +75,6 @@ def code
     end
     memoize :code
 
-    # Normalized mutation source
-    #
-    # @return [String]
-    def source
-      Unparser.unparse(node)
-    end
-    memoize :source
-
     # Identification string
     #
     # @return [String]
@@ -75,10 +125,6 @@ def insert(kernel)
       end
     end
 
-    # Rendered mutation diff
-    #
-    # @return [String, nil]
-    #   the diff, if present
     def diff
       Unparser::Diff.build(original_source, source)
     end

lib/mutant/mutator/node/and_asgn.rb

@@ -14,7 +14,6 @@ class AndAsgn < self
       private
 
         def dispatch
-          emit_singletons
           emit_left_mutations do |node|
             !n_self?(node)
           end