/\p{Latin}/ crashes mutator

[backus]

Versions:

$ ruby -v
ruby 2.6.7p197 (2021-04-05 revision 67941) [x86_64-darwin20]

$ bundle exec mutant run -v
mutant-0.10.30

$ bundle list
Gems included by the bundle:
  * ast (2.4.2)
  * diff-lcs (1.4.4)
  * mutant (0.10.30)
  * mutant-license (0.1.1.1.3319570810364303218730943090542303819067.3)
  * mutant-rspec (0.10.30)
  * parser (3.0.1.0)
  * regexp_parser (2.1.1)
  * rspec (3.10.0)
  * rspec-core (3.10.1)
  * rspec-expectations (3.10.1)
  * rspec-mocks (3.10.2)
  * rspec-support (3.10.2)
  * unparser (0.6.0)

Source triggering crash:

module MutantCrash
  def self.crash_the_mutant
    /\p{Latin}/
  end
end

Crash:

$ bundle exec mutant run --include lib --require example --use rspec 'MutantCrash*'
No examples found.
/dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/ast/regexp.rb:24:in `to_ast': undefined method `to_ast' for Mutant::Mutator::Node::Generic:Class (NoMethodError)
Did you mean?  to_s
	from /dev/.rvm/gems/ruby-2.6.7/gems/regexp_parser-2.1.1/lib/regexp_parser/expression/subexpression.rb:32:in `each'
	from /dev/.rvm/gems/ruby-2.6.7/gems/regexp_parser-2.1.1/lib/regexp_parser/expression/subexpression.rb:32:in `each'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/ast/regexp/transformer.rb:67:in `map'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/ast/regexp/transformer.rb:67:in `children'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/ast/regexp/transformer/recursive.rb:15:in `call'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/procto.rb:19:in `call'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/ast/regexp/transformer.rb:36:in `to_ast'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/ast/regexp.rb:24:in `to_ast'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/ast/regexp.rb:50:in `expand_regexp_ast'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator/node/literal/regex.rb:34:in `mutate_body'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator/node/literal/regex.rb:22:in `dispatch'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator.rb:47:in `initialize'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:78:in `new'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:78:in `new'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/abstract_type.rb:40:in `block in create_new_method'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/abstract_type.rb:40:in `block in create_new_method'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/abstract_type.rb:40:in `block in create_new_method'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/procto.rb:19:in `call'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator.rb:23:in `mutate'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator/node.rb:42:in `mutate_child'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator/node.rb:26:in `block in define_named_child'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator/node/define.rb:17:in `dispatch'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator.rb:47:in `initialize'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:78:in `new'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:78:in `new'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/abstract_type.rb:40:in `block in create_new_method'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/abstract_type.rb:40:in `block in create_new_method'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/procto.rb:19:in `call'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/mutator.rb:23:in `mutate'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/subject.rb:15:in `mutations'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium/method_builder.rb:91:in `call'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium/method_builder.rb:91:in `block (3 levels) in create_memoized_method'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:62:in `block (3 levels) in fetch'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:61:in `fetch'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:61:in `block (2 levels) in fetch'
	from /dev/.rvm/rubies/ruby-2.6.7/lib/ruby/2.6.0/monitor.rb:235:in `mon_synchronize'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:60:in `block in fetch'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:59:in `fetch'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium.rb:59:in `fetch'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/adamantium/method_builder.rb:90:in `block (2 levels) in create_memoized_method'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/bootstrap.rb:43:in `each'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/bootstrap.rb:43:in `flat_map'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/bootstrap.rb:43:in `block in call'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/either.rb:108:in `fmap'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/bootstrap.rb:40:in `call'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/cli/command/environment.rb:28:in `block in bootstrap'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/either.rb:115:in `bind'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/cli/command/environment.rb:28:in `bootstrap'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/cli/command/environment/run.rb:30:in `block in action'
	from /dev/.rvm/gems/ruby-2.6.7/gems/unparser-0.6.0/lib/unparser/either.rb:115:in `bind'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/cli/command/environment/run.rb:30:in `action'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/cli/command.rb:79:in `execute'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/lib/mutant/cli/command.rb:55:in `call'
	from /dev/.rvm/gems/ruby-2.6.7/gems/mutant-0.10.30/bin/mutant:47:in `<top (required)>'
	from /dev/.rvm/gems/ruby-2.6.7/bin/mutant:23:in `load'
	from /dev/.rvm/gems/ruby-2.6.7/bin/mutant:23:in `<main>'
	from /dev/.rvm/gems/ruby-2.6.7/bin/ruby_executable_hooks:22:in `eval'
	from /dev/.rvm/gems/ruby-2.6.7/bin/ruby_executable_hooks:22:in `<main>'

[mbj]

Very likely an incomplete Regexp -> AST mapper, or a regression on mutants regexp support.

I think we need a bigger corpus test for regexps. I'll try to hook up the regexp_parser tests.

Thanks for the report.

[mbj]

I have a potential fix, hope to be able to push it up tomorrow.

[mbj]

@backus Thanks for the report, released a fix and some improvements on the error reporting for similar cases with 0.10.31.

Happy mutating.