| Subject: | pipelined response deadlock |
| Date: | Fri, 4 Jan 2013 16:27:07 +0000 |
| To: | bug-mod_perl [...] rt.cpan.org |
| From: | Zefram <zefram [...] fysh.org> |
There's a race condition that can cause mod_perl's test suite to hang
in t/filter/in_str_declined.t. The problem is that the response handler
starts generating response body, and so triggers header output, before
it reads the request body. If LWP::Protocol::http, which is the client
for this test, receives a complete set of response headers, it will stop
sending the request body. (However, if the request body is no more than
8192 octets then it will send the whole body before it starts looking
for a response. The failure only shows up with an appreciably large
request body.)
RFC 2616 doesn't explicitly address this sort of pipelining, but the
start of section 6 does say "After receiving and interpreting a request
message, a server responds with an HTTP response message.", which can be
read as prohibiting sending any part of the response before the entire
request has been received.
The attached patch fixes this issue by making all the POST handlers in
the test suite read the body before doing anything that generates output
(specifically plan()).
-zefram
Message body is not shown because sender requested not to inline it.