Async::HTTP causes error with io-stream 0.8.0

[Watson1978]

After updating io-stream to the latest version, Async::HTTP causes errors on Windows platform.
We met this problem with Ruby 3.3 and 3.4 on Windows.

Reproduce

require 'bundler/inline'
gemfile do
  source 'https://rubygems.org'
#  gem 'io-stream', '= 0.7.0'
  gem 'io-stream', '= 0.8.0'
  gem 'async'
  gem 'async-http'
end

require 'net/http'
require 'uri'

endpoint = Async::HTTP::Endpoint.parse('http://127.0.0.1:8080/hello')

Thread.new do
  Sync do |task|
    Async do
      server = Async::HTTP::Server.for(endpoint) do |request|
        ::Protocol::HTTP::Response[200, {}, ["Hello World"]]
      end

      server.run
    end
  end
end

sleep 1

url = URI.parse("http://127.0.0.1:8080/hello")
req = Net::HTTP::Get.new(url)
Net::HTTP.start(url.host, url.port) do |http|
  puts "-" * 80
  puts "[debug] Requesting #{url}"
  puts http.request(req).body
end

sleep 1

• Result with io-stream v0.8.0

PS C:\src\sandbox\ruby> ruby net.rb
C:/Ruby34-x64/lib/ruby/3.4.0/win32/registry.rb:2: warning: fiddle/import is found in fiddle, which will no longer be part of the default gems starting from Ruby 3.5.0.
You can add fiddle to your Gemfile or gemspec to silence this warning.
--------------------------------------------------------------------------------
[debug] Requesting http://127.0.0.1:8080/hello
  0.0s     warn: Async::Task: Reading HTTP/1.1 requests for Async::HTTP::Protocol::HTTP1::Server. [oid=0x318] [ec=0x320] [pid=9604] [2025-06-24 17:03:08 +0900]
               | Task may have ended with unhandled exception.
               |   Errno::EBADF: Bad file descriptor
               |   → C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/buffered.rb 111:in 'IO#write'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/buffered.rb 111:in 'IO::Stream::Buffered#syswrite'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 85:in 'IO::Stream::Writable#drain'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 33:in 'block in IO::Stream::Writable#flush'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 32:in 'Thread::Mutex#synchronize'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 32:in 'IO::Stream::Writable#flush'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb 623:in 'Protocol::HTTP1::Connection#write_fixed_length_body'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb 751:in 'Protocol::HTTP1::Connection#write_body'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/protocol/http1/server.rb 134:in 'block in Async::HTTP::Protocol::HTTP1::Server#each'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 331:in 'Async::Task#defer_stop'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/protocol/http1/server.rb 81:in 'Async::HTTP::Protocol::HTTP1::Server#each'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/server.rb 50:in 'Async::HTTP::Server#accept'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-endpoint-0.15.2/lib/io/endpoint/wrapper.rb 216:in 'block (2 levels) in IO::Endpoint::Wrapper#accept'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 201:in 'block in Async::Task#run'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 439:in 'block in Async::Task#schedule'
 0.03s     warn: Async::Task: Reading HTTP/1.1 requests for Async::HTTP::Protocol::HTTP1::Server. [oid=0x328] [ec=0x330] [pid=9604] [2025-06-24 17:03:08 +0900]
               | Task may have ended with unhandled exception.
               |   Errno::EBADF: Bad file descriptor
               |   → C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/buffered.rb 111:in 'IO#write'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/buffered.rb 111:in 'IO::Stream::Buffered#syswrite'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 85:in 'IO::Stream::Writable#drain'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 33:in 'block in IO::Stream::Writable#flush'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 32:in 'Thread::Mutex#synchronize'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-stream-0.8.0/lib/io/stream/writable.rb 32:in 'IO::Stream::Writable#flush'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb 623:in 'Protocol::HTTP1::Connection#write_fixed_length_body'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/protocol-http1-0.34.0/lib/protocol/http1/connection.rb 751:in 'Protocol::HTTP1::Connection#write_body'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/protocol/http1/server.rb 134:in 'block in Async::HTTP::Protocol::HTTP1::Server#each'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 331:in 'Async::Task#defer_stop'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/protocol/http1/server.rb 81:in 'Async::HTTP::Protocol::HTTP1::Server#each'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-http-0.89.0/lib/async/http/server.rb 50:in 'Async::HTTP::Server#accept'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/io-endpoint-0.15.2/lib/io/endpoint/wrapper.rb 216:in 'block (2 levels) in IO::Endpoint::Wrapper#accept'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 201:in 'block in Async::Task#run'
               |     C:/Ruby34-x64/lib/ruby/gems/3.4.0/gems/async-2.25.0/lib/async/task.rb 439:in 'block in Async::Task#schedule'
C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:237:in 'Net::BufferedIO#rbuf_fill': end of file reached (EOFError)
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:199:in 'Net::BufferedIO#readuntil'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/protocol.rb:209:in 'Net::BufferedIO#readline'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http/response.rb:158:in 'Net::HTTPResponse.read_status_line'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http/response.rb:147:in 'Net::HTTPResponse.read_new'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2414:in 'block in Net::HTTP#transport_request'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2405:in 'Kernel#catch'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2405:in 'Net::HTTP#transport_request'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:2378:in 'Net::HTTP#request'
	from net.rb:32:in 'block in <main>'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:1626:in 'Net::HTTP#start'
	from C:/Ruby34-x64/lib/ruby/3.4.0/net/http.rb:1064:in 'Net::HTTP.start'
	from net.rb:29:in '<main>'

it causes error with same net/http stacktrace.

• Result with io-stream v0.7.0

PS C:\src\sandbox\ruby> ruby net.rb
C:/Ruby34-x64/lib/ruby/3.4.0/win32/registry.rb:2: warning: fiddle/import is found in fiddle, which will no longer be part of the default gems starting from Ruby 3.5.0.
You can add fiddle to your Gemfile or gemspec to silence this warning.
--------------------------------------------------------------------------------
[debug] Requesting http://127.0.0.1:8080/hello
Hello World

it works well

Related to fluent/fluentd#5009

[ioquatix]

Thanks for the report I will check it tonight.

[Watson1978]

The latest version works well.
Thanks!!

[ioquatix]

I am so happy to hear that, I did not specifically set out to address this issue but worked at the foundation to try and improve Windows testing and fixed the bugs that showed up. I'm glad this is now resolved.

Windows IO semantics is extremely frustrating at times.

Please keep an eye out for issues or regressions and report them if you find them :) We will try to make things better. My longer term plan is to use IOCP but it will take a year or two to prioritise it.

[daipom]

@ioquatix
Thanks so much for your kind response!
Fluentd team has found that this issue has been fixed by io-event >= 1.12.0.

• If io-stream <= 0.7, this issue does not occur.
• If io-stream >= 0.8, needs io-event >= 1.12.0 to avoid this issue.

It is important to note that simply upgrading the version of io-stream will not solve the issue.

[ioquatix]

It is likely to be this change: fb9f443

And the fix is likely to be this change: socketry/io-event@a33306a

[daipom]

Thanks!