From: "leocassarani (Leo Cassarani)" <leo.cassarani@...>
Date: 2013-05-02T23:12:24+09:00
Subject: [ruby-core:54746] [ruby-trunk - Bug #8342] IO.readlines ignores Encoding.default_internal if Encoding.default_external is ASCII-8BIT


Issue #8342 has been updated by leocassarani (Leo Cassarani).


Thanks naruse. However, this seems inconsistent with the way encodings are handled for individual IO instances. For example:

io = File.open('hi', :encoding => "ascii-8bit:utf-16")
puts io.gets.encoding
# => UTF-16

This happens even if Encoding.default_external is set to ASCII-8BIT before opening the file.
----------------------------------------
Bug #8342: IO.readlines ignores Encoding.default_internal if Encoding.default_external is ASCII-8BIT
https://bugs.ruby-lang.org/issues/8342#change-39086

Author: leocassarani (Leo Cassarani)
Status: Rejected
Priority: Normal
Assignee: naruse (Yui NARUSE)
Category: M17N
Target version: current: 2.1.0
ruby -v: 1.9.3
Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN


Under normal circumstances, IO.readlines will transcode from Encoding.default_external to Encoding.default_internal:

File.open('hi', 'w') { |f| f.puts "hello\n" }
Encoding.default_external = Encoding::US_ASCII
Encoding.default_internal = Encoding::UTF_8
puts IO.readlines('hi').first.encoding
#=> UTF-8

However, when Encoding.default_external is set to ASCII-8BIT, IO.readlines will always use ASCII-8BIT, regardless of what Encoding.default_internal is set to:

File.open('hi', 'w') { |f| f.puts "hello\n" }
Encoding.default_external = Encoding::ASCII_8BIT
Encoding.default_internal = Encoding::UTF_8
puts IO.readlines('hi').first.encoding
#=> ASCII-8BIT

Using IO#gets instead of IO.readlines will produce the same behaviour.


-- 
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