Using HTTP PUT method for binary StringIO body fails with ruby 3.4.x

[jarl-dk]

There is a difference in StringIO#read behaviour between ruby 3.3.x and 3.4.x.

The difference is illustrated by this:

Ruby 3.3.7:

irb(main):001> RUBY_VERSION
=> "3.3.7"
irb(main):002> binary_io = StringIO.new("\x00".b)
=> #<StringIO:0x00007f50541b8518>
irb(main):003> buf = ''
=> ""
irb(main):004> buf.encoding
=> #<Encoding:UTF-8>
irb(main):005> binary_io.read(1, buf)
=> "\x00"
irb(main):006> buf.encoding
=> #<Encoding:ASCII-8BIT>

Ruby 3.4.0:

irb(main):001> RUBY_VERSION
=> "3.4.0"
irb(main):002> binary_io = StringIO.new("\x00".b)
=> #<StringIO:0x000071c808fafab8>
irb(main):003> buf = ''
=> ""
irb(main):004> buf.encoding
=> #<Encoding:UTF-8>
irb(main):005> binary_io.read(1, buf)
=> "\u0000"
irb(main):006> buf.encoding
=> #<Encoding:UTF-8>

I experience that this new beahaviour affects httpclient when using StringIO as body on PUT requests:

httpclient/lib/httpclient/http.rb

Line 580 in d57cc6d

n = io.read([rest, @chunk_size].min, buf)

This may very well also affect other http methods. I have not tried.

The workaround is not to upgrade ruby to 3.4.x