When you type a command in pdb that happens to print something, the
output goes to sys.stdout, even if self.stdout references another file.
 This makes it hard to debug code running inside a web server where
sys.stdout/stdout are connected to a socket (or a WSGI wrapper file);
the output "disappears" and ends up messing up the response.

Attached is a fix that temporarily changes sys.stdin/stdout to the
debugger's input and output.  What do people think of this?