stream_input: read with zero length returns ''

Any calls to read with an explicit zero length now returns an
empty string.  While not explicitly specified by Rack::Lint,
this is for compatibility with StringIO and IO methods which
are common in other web servers.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/unicorn/stream_input.rb b/lib/unicorn/stream_input.rb
index 2c8e40a..ef8997e 100644
--- a/lib/unicorn/stream_input.rb
+++ b/lib/unicorn/stream_input.rb
@@ -60,7 +60,7 @@ class Unicorn::StreamInput
           @rbuf.replace('')
         end
       end
-      rv = nil if rv.empty?
+      rv = nil if rv.empty? && length != 0
     end
     rv
   end