puma: Error in reactor loop escaped: System error: Undefined error: 0 - 0 (Puma::MiniSSL::SSLError)

I am setting up capybara to use SSL through puma. It all works in terms of connectivity, but this gets putsed out to STDOUT and I can find no way to fix it or silence it. I’m ok with either as a solution.

Steps to reproduce

1. Setup SSL as such:

# https://gist.github.com/tadast/9932075
if Rails.env.test?
  unless File.exist?(Rails.root.join('config', 'ssl', 'localhost.test.key'))
    def generate_root_cert(root_key)
      root_ca = OpenSSL::X509::Certificate.new
      root_ca.version = 2 # cf. RFC 5280 - to make it a "v3" certificate
      root_ca.serial = 0x0
      root_ca.subject = OpenSSL::X509::Name.parse "/C=BE/O=A1/OU=A/CN=localhost.test"
      root_ca.issuer = root_ca.subject # root CA's are "self-signed"
      root_ca.public_key = root_key.public_key
      root_ca.not_before = Time.now
      root_ca.not_after = root_ca.not_before + 2 * 365 * 24 * 60 * 60 # 2 years validity
      root_ca.sign(root_key, OpenSSL::Digest::SHA256.new)
      root_ca
    end

    root_key = OpenSSL::PKey::RSA.new(2048)
    file = File.new( Rails.root.join('config', 'ssl', 'localhost.test.key'), "wb")
    file.write(root_key)
    file.close

    root_cert = generate_root_cert(root_key)

    file = File.new( Rails.root.join('config','ssl', 'localhost.test.crt'), "wb")
    file.write(root_cert)
    file.close
  end
    
  ssl_bind 'localhost.test', 3000, {
    key: Rails.root.join('config','ssl', 'localhost.test.key'),
    cert: Rails.root.join('config','ssl', 'localhost.test.crt'),
    verify_mode: 'none'
  }
end

1. Run Rspec feature specs using capybara, headless chrome, and puma

# https://robots.thoughtbot.com/headless-feature-specs-with-chrome
Capybara.register_driver :chrome do |app|
  Capybara::Selenium::Driver.new(app, browser: :chrome)
end

Capybara.register_driver :headless_chrome do |app|
  capabilities = Selenium::WebDriver::Remote::Capabilities.chrome(
    chromeOptions: {
      args: %w(headless disable-gpu),
      'profile.managed_default_content_settings.notifications': 2,
    }
  )
  
  profile = Selenium::WebDriver::Chrome::Profile.new
  profile["profile.default_content_settings"] = { images: '2' }

  options = Selenium::WebDriver::Chrome::Options.new(args: ['headless', '--blink-settings=imagesEnabled=false'])

  Capybara::Selenium::Driver.new app,
    browser: :chrome,
    desired_capabilities: capabilities,
    profile: profile,
    options: options
end

Capybara.javascript_driver = :headless_chrome
# If you’d like to watch the tests execute while debugging, you can change the driver to chrome.
# Capybara.javascript_driver = :chrome
# Screenshot with save_and_open_screenshot





key_file = Rails.root.join('config', 'ssl', 'localhost.test.key')
cert_file = Rails.root.join('config', 'ssl', 'localhost.test.crt')

Capybara.server = :puma, {
  Silent: true,
  Host: "ssl://#{Capybara.server_host}:#{Capybara.server_port}?key=#{key_file}&cert=#{cert_file}"
}

Expected behavior

I would expect Silent: true to actually keep things silent.

Actual behavior

I get the following puts on every run:

Error in reactor loop escaped: System error: Undefined error: 0 - 0 (Puma::MiniSSL::SSLError)
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/minissl.rb:41:in `read'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/minissl.rb:41:in `engine_read_all'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/minissl.rb:52:in `read_nonblock'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/minissl.rb:127:in `read_and_drop'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/minissl.rb:144:in `close'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/client.rb:123:in `close'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/reactor.rb:212:in `rescue in block in run_internal'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/reactor.rb:170:in `block in run_internal'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/reactor.rb:140:in `each'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/reactor.rb:140:in `run_internal'
/Users/[REDACTED]/.rvm/gems/ruby-2.5.3@[REDACTED]/gems/puma-3.12.0/lib/puma/reactor.rb:251:in `block in run_in_thread'

System configuration

Ruby version: 2.5.3 Rails version: 5.2.2 Puma version: 3.12.0