Bug #5568: IO#set_encoding ignores internal when the same as external only when specified as "ext:int"

• Status: Closed
• Assignee: naruse (Yui NARUSE)
• Target version: -
• ruby -v: ruby 2.0.0dev (2011-10-26 trunk 33526) [x86_64-darwin10.8.0]

[brixen (Brian Shirai)]

When passing two encoding objects that are the same to IO#set_encoding, both external and internal encodings for the IO instance are set.

However, when passing "ext:int", the internal encoding is not set if the same as external, but a warning is issued. Further, when passing "ext", "int", the internal encoding is not set and no warning is issued.

sasha:rubinius brian$ ruby2.0 -v -e 'p STDOUT.set_encoding("utf-8:utf-8").internal_encoding'
ruby 2.0.0dev (2011-10-26 trunk 33526) [x86_64-darwin10.8.0]
-e:1: warning: Ignoring internal encoding utf-8: it is identical to external encoding utf-8
nil

sasha:rubinius brian$ ruby2.0 -v -e 'p STDOUT.set_encoding(Encoding::UTF_8, Encoding::UTF_8).internal_encoding'
ruby 2.0.0dev (2011-10-26 trunk 33526) [x86_64-darwin10.8.0]
#Encoding:UTF-8

sasha:rubinius brian$ ruby2.0 -v -e 'p STDOUT.set_encoding("utf-8", "utf-8").internal_encoding'
ruby 2.0.0dev (2011-10-26 trunk 33526) [x86_64-darwin10.8.0]
nil

Is there a reason for these differences?

Thanks,
Brian

[naruse (Yui NARUSE)]

• Category set to M17N
• Status changed from Open to Assigned
• Assignee set to naruse (Yui NARUSE)

[naruse (Yui NARUSE)]

• Status changed from Assigned to Rejected

Current behavior is correct.
It means the specifying internal encoding won't effect until external encoding is changed.

[brixen (Brian Shirai)]

Why is there a difference in behavior when the arguments are different? In other words, ("ext:int") and (ext, int) do not have the same behavior. That's really the point of this ticket.

[naruse (Yui NARUSE)]

• Status changed from Rejected to Assigned

[naruse (Yui NARUSE)]

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r34997.
Brian, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

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• io.c (io_encoding_set): always warn if external encoding and internal
  encoding are identical. [ruby-core:40727] [Bug #5568]