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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Style/ClassAndModuleChildren not safe within module or class","articleBody":"The Style/ClassAndModuleChildren cop is not safe to correct when the code occurs within another scope. This led to a bug in JRuby's build when using automated corrections.\n\nNested module access will not walk up to the toplevel to look for modules or classes to open, while path-based access does do this.\n\n--------\n\n## Expected behavior\n\nCode below should behave this way before or after correction, or else it should be considered an unsafe correction.\n\nOriginal code:\n\n```ruby\nmodule X\n  module Y\n    puts object_id\n  end\nend\nmodule Z\n  module X::Y\n    puts object_id\n  end\nend\n# prints same object id for Y, because path-based access uses the toplevel X\n# and reopens the existing modules\n```\n\n## Actual behavior\n\nWhen corrected to nested modules, the reopen of X creates a new module tree rather than accessing the toplevel X.\n\nCorrected code:\n\n```ruby\n...\nmodule Z\n  module X\n    module Y\n      puts object_id\n    end\n  end\nend\n# Reopen of X is a new module and Y is also new with a different object_id\n```\n\nFull script example of the behavior:\n\n```ruby\nmodule X\n  module Y\n    puts object_id\n  end\nend\nmodule Z\n  module X::Y\n    puts object_id\n  end\nend\nmodule Q\n  module X\n    module Y\n      puts object_id\n    end\n  end\nend\n```\n\nOutput from example, showing that the correction is not safe:\n\n```\n$ cx 3.4 ruby -v blah.rb\nruby 3.4.5 (2025-07-16 revision 20cda200d3) +PRISM [arm64-darwin24]\n16\n16\n24\n```\n\n## RuboCop version\n\n```\n$ rubocop -V\n1.80.0 (using Parser 3.3.9.0, rubocop-ast 1.46.0, analyzing as Ruby 2.7, running on jruby 3.1.7) [java]\n```","author":{"url":"https://github.com/headius","@type":"Person","name":"headius"},"datePublished":"2025-08-25T18:12:52.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/14476/rubocop/issues/14476"}