From: Run Paint Run Run <runrun@...>
Date: 2010-09-02T15:32:36+09:00
Subject: [ruby-core:32007] Re: not use system for default encoding

> $ cat test.rb
> p File.read('other_file_unknown_encoding').encoding
> p 'abc'.encoding
>
> $ ruby test.rb
> #<Encoding:IBM437>
> #<Encoding:US-ASCII>
>
> for better or worse, even though 'other_file_unknown_encoding' has
> only ASCII characters, its encoding is set to my system default. ��This
> means that if I package up the file "other_file_unknown_encoding" in
> my gem, and read it later, I *must* specify its encoding when I read
> it. ��So it will succeed locally and *fail* on another box, which to me
> adds extra confusion.

No. You can show this is not the case yourself by specifying a different
default external encoding, then reading in a file. If the file is ASCII-only,
it can be read under any ASCII-compatible external encoding without you having
to specify a thing. Your file is valid, and identical, in any of these
encodings, so the precise one chosen is immaterial.

  run@paint:/tmp ���  echo "aheh&^^Gah*" >ascii
  run@paint:/tmp ���  irb
  >> File.read('ascii').hash
  => -971653016
  >> File.read('ascii', encoding: 'ibm437').hash
  => -971653016
  >> File.read('ascii', encoding: 'utf-8').hash
  => -971653016
  >> File.read('ascii', encoding: 'big5').hash
  => -971653016
  >> Encoding.default_external='shift_jis'
  => "shift_jis"
  >> File.read('ascii').encoding
  => #<Encoding:Shift_JIS>
  >> File.read('ascii').hash
  => -971653016

> The other surprising thing to me is that it assigns IBM437 not only to
> terminal input but also to file input. ��*Nobody* edits files in
> IBM437. ��It feels inappropriate to use that for the encoding, or,
> really, to have a default for file encoding.

I know little of Windows matters, but surely if that���s your system locale, it
is indeed the default encoding for editing files. Certainly, your text editor
has presumably been configured to use something more sensible, but if not
wouldn���t it fallback to IBM437?