[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?