I found an interesting bug today. When sending a form multipart > 112KB, I noticed that Rack::Request#params was empty. This only occurs when using Unicorn, and does not occur when using Thin.
I dug into Rack source and noticed that any EOFError raised while reading the body input stream will cause the post body input stream to be ignored: https://github.com/rack/rack/blob/cabaa58fe6ac355623746e287475af88c9395d66/lib/rack/request.rb#L357 When multipart > 112KB, I noticed that Unicorn tees the input stream to a temporary file. I was wondering: might Unicorn::TeeInput raise an EOFError as part of normal operation when reaching the end of the input stream? If so, this would break the Rack spec. I only tested this on Darwin, still working on a self-contained repro. I ended up raising client_body_buffer_size to 1MB as a work-around. I'm wondering if this is a bug?
