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RubyParser: slice comments by byte offset - #4376
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kddnewton merged 1 commit intoNov 14, 2026
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attach_comments used prism's byte offsets to index the source string with String#[], which counts characters. With multibyte characters before a def, the slice was taken at the wrong place: the comments could include the code after them, be dropped entirely, or raise NoMethodError when the slice ran past the end of the string. Use String#byteslice instead. Fixes ruby#4369
kddnewton
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Nov 14, 2026
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Fixes #4369.
attach_commentsslicedsource_stringwithString#[]using prism's byte offsets, butString#[]counts characters. With multibyte characters in the comments before adef, the slice landed in the wrong place:"# ああああああ\ndef x; end\n": the comments includeddef x; end"# あああああああ\ndef x; end\n": NoMethodError (undefined method 'match?' for nil)"# é\n# 日本語\n\n# ü\ndef x; end\n": the comments were dropped (nil)This uses
String#byteslicefor both slices. The new test compares the comments withruby_parserfor those three sources. It fails without the change.bundle exec rake testpasses.