Bug #19235: StringIO.new(encoding: "ext_enc:int_enc") doesn't set external encoding

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: 3.1.2
• Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN

[andrykonchin (Andrew Konchin)]

I noticed a divergence between IO :encoding option documentation and StringIO's behaviour:

io = StringIO.new('', 'w', encoding: 'utf-8:ISO-8859-1')
io.external_encoding # => #<Encoding:ISO-8859-1>

According to the documentation:

:encoding: Specifies external and internal encodings as 'extern:intern'.

The IO class behaves in expected way:

f = File.open("test.txt", 'w', encoding: 'UTF-8:ISO-8859-1')
f.external_encoding # => #<Encoding:UTF-8>

[zverok (Victor Shepelev)]

• Related to Bug #16497: StringIO#internal_encoding is broken (more severely in 2.7) added

[zverok (Victor Shepelev)]

The StringIO doesn't have a proper concept of two encodings implemented :(
Also reported here #16497 but still not fixed completely.

I'll try to look into it this weekend.

[zverok (Victor Shepelev)]

Though it is kinda specified in README :)))

encoding conversion is not implemented, and ignored silently.

[andrykonchin (Andrew Konchin)]

• Description updated (diff)

[andrykonchin (Andrew Konchin)]

Yeah, so this issue is a duplicate. My bad (.

So this issue probably should be closed. I don't have permissions to close it myself. Could anybody close it?

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed