From: "naruse (Yui NARUSE)" Date: 2013-04-29T14:00:05+09:00 Subject: [ruby-core:54682] [ruby-trunk - Bug #8342][Rejected] IO.readlines ignores Encoding.default_internal if Encoding.default_external is ASCII-8BIT Issue #8342 has been updated by naruse (Yui NARUSE). Status changed from Assigned to Rejected If external encoding is ASCII-8BIT, the input content is considered as binary. It is out of text encoding conversion and its encoding kept as ASCII-8BIT even if default_internal is set. ---------------------------------------- Bug #8342: IO.readlines ignores Encoding.default_internal if Encoding.default_external is ASCII-8BIT https://bugs.ruby-lang.org/issues/8342#change-39028 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. -- http://bugs.ruby-lang.org/