I an attempt to use non-blocking IO to work around the same issue for IO#gets, I discovered that IO.select cannot be interrupted by Timeout::timeout.

I expected the following to work:

read, write = IO.pipe
Timeout::timeout(1) do
  IO.select([read])
end

So long as the read end of the pipe receives no data, and is not closed, this will block forever.

I found that the following results in the desired behavior:

read, write = IO.pipe
Timeout::timeout(1) do
  Thread.new { IO.select([read]) }.join
end

Ideally, Timeout::timeout would not block for IO#gets or IO.select. I've implemented this workaround in capybara-webkit but would prefer a proper solution.