From: "Eregon (Benoit Daloze) via ruby-core" Date: 2023-08-24T15:08:28+00:00 Subject: [ruby-core:114494] [Ruby master Bug#19784] String#delete_prefix! problem Issue #19784 has been updated by Eregon (Benoit Daloze). mame (Yusuke Endoh) wrote in #note-5: > Note that encoding validity is checked on a position-by-position basis: That's not clear to me. Do you mean that if the argument or if the receiver String is not `String#valid_encoding?`, then we compare byte-by-byte, and otherwise we compare character-by-character ? I think we should not consider whether a given substring is valid, that would be very expensive to check. I wonder if always comparing byte-by-byte for both is not a lot simpler, faster, and also what most users expect. And of course still have the encoding check to ensure both strings have a compatible encoding. ---------------------------------------- Bug #19784: String#delete_prefix! problem https://bugs.ruby-lang.org/issues/19784#change-104279 * Author: inversion (Yura Babak) * Status: Open * Priority: Normal * ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux] * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Here is the snipped and the question is in the comments: ``` ruby fp = 'with_BOM_16.txt' body = File.read(fp).force_encoding('UTF-8') p body # "\xFF\xFE1\u00001\u0000" p body.start_with?("\xFF\xFE") # true body.delete_prefix!("\xFF\xFE") # !!! why doesn't work? p body # "\xFF\xFE1\u00001\u0000" p body.start_with?("\xFF\xFE") # true body[0, 2] = '' p body # "1\u00001\u0000" p body.start_with?("\xFF\xFE") # false ``` Works same on Linux (ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-linux]) and Windows (ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x64-mingw-ucrt]) -- https://bugs.ruby-lang.org/ ______________________________________________ ruby-core mailing list -- ruby-core@ml.ruby-lang.org To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/