From: "andrykonchin (Andrew Konchin) via ruby-core" <ruby-core@...>
Date: 2024-01-14T23:15:32+00:00
Subject: [ruby-core:116210] [Ruby master Bug#20185] String#ascii_only? buggy in ruby 3.3

Issue #20185 has been updated by andrykonchin (Andrew Konchin).





I cannot reproduce the issue with plain String (without StringIO) on Ruby 3.2, 3.1 and 3.0. `ascii_only?` reports `false` for "����������":



```

ruby -e 'p "����������".ascii_only?'

false

```



I believe in the examples involving StringIO the observed behaviour is caused by preserving `StringIO#string`'s encoding. StringIO instance is initialised with a String literal in `binary` encoding. And any modification like writing doesn't change encoding even when a UTF-8 String is written:



```ruby

io = StringIO.new "".b

io.string.encoding # => #<Encoding:ASCII-8BIT>



io.write "���"

io.string.encoding # => #<Encoding:ASCII-8BIT>

```



----------------------------------------

Bug #20185: String#ascii_only? buggy in ruby 3.3

https://bugs.ruby-lang.org/issues/20185#change-106230



* Author: chucke (Tiago Cardoso)

* Status: Open

* Priority: Normal

* ruby -v: 3.3.0

* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN

----------------------------------------

This was the smallest reduction of the bug I could come up with:



    require "stringio"



    puts StringIO::VERSION



    def is_ascii(buffer)

      str = buffer.string

      puts "\"#{str}\" is ascii: #{str.ascii_only?}"

    end



    buffer = StringIO.new("".b)



    buffer.write("a=b&c=d")

    buffer.rewind

    is_ascii(buffer)

    buffer.write "����������"

    is_ascii(buffer)



    # in ruby 3.3

    #=> 3.1.0

    #=> "a=b&c=d" is ascii: true

    #=> "����������" is ascii: true



    # in ruby 3.2

    #=> 3.0.4

    #=> "a=b&c=d" is ascii: true

    #=> "����������" is ascii: true



    # in ruby 3.1

    #=> 3.0.1

    #=> "a=b&c=d" is ascii: true

    #=> "����������" is ascii: false



I believe that only the 3.1 result is correct, as "����������" first character is not ascii.







-- 

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/