[ruby-core:115751] [Ruby master Bug#20067] IO.pipe `int_enc` and `ext_enc` not working as documented?

Issue #20067 has been reported by byroot (Jean Boussier).

----------------------------------------
Bug #20067: IO.pipe `int_enc` and `ext_enc` not working as documented?
https://bugs.ruby-lang.org/issues/20067

* Author: byroot (Jean Boussier)
* Status: Open
* Priority: Normal
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN
----------------------------------------
>From the documentation:

> pipe(ext_enc, int_enc, **opts)

> If argument int_enc is given, it must be an Encoding object or encoding name string that specifies the internal encoding to be used; if argument ext_enc is also given, it must be an Encoding object or encoding name string that specifies the external encoding to be used.

Test script:

```ruby
ios = IO.pipe(Encoding::BINARY, Encoding::BINARY)

p [:internal, *ios.map(&:internal_encoding)]
p [:external, *ios.map(&:external_encoding)]

Encoding.default_internal = Encoding::UTF_8
Encoding.default_external = Encoding::UTF_8

ios = IO.pipe(Encoding::BINARY, Encoding::BINARY)

p [:internal, *ios.map(&:internal_encoding)]
p [:external, *ios.map(&:external_encoding)]
```

Actual output:

```
[:internal, nil, nil]
[:external, #<Encoding:ASCII-8BIT>, nil]
[:internal, nil, nil]
[:external, #<Encoding:ASCII-8BIT>, #<Encoding:UTF-8>]
```

Expected output:


```
[:internal, #<Encoding:ASCII-8BIT>, #<Encoding:ASCII-8BIT>]
[:external, #<Encoding:ASCII-8BIT>, #<Encoding:ASCII-8BIT>]
[:internal, #<Encoding:ASCII-8BIT>, #<Encoding:ASCII-8BIT>]
[:external, #<Encoding:ASCII-8BIT>, #<Encoding:ASCII-8BIT>]
```

Am I reading the documentation incorrectly, or is it just not working as claimed?

I tried on older versions, and it seems to have been like that all the way down to Ruby 1.9.

The only reliable way I found to have a "binary" pipe is to call `IO#binmode`. 



-- 
https://bugs.ruby-lang.org/
 ______________________________________________
 ruby-core mailing list -- [e-mail]
 To unsubscribe send an email to [e-mail]
 ruby-core info -- https://ml.ruby-lang.org/mailman3/postorius/lists/ruby-core.ml.ruby-lang.org/