Validation of atom feeds via rawdata fails

Hi all,

I've received a recent report that the "direct input" interface to  
the feed validator at http://validator.w3.org/feed/, which uses the  
rawdata feature of the feedvalidator, was failing for a number of  
atom feeds, but working just fine with other types of feed.

Steps to reproduce:
1) go to http://validator.w3.org/feed/
2) paste in the "direct input" box the content of an atom feed, e.g  
http://validator.w3.org/whatsnew.atom
3) Submit the form

Result: validation fails, no error given


Note that the service is using the latest svn code (as of Aug 18,  
2006), but the problem has been present at least since the last  
codebase sync, at the end of July.


I have managed to tweak check.cgi a little to get a full trace of the  
problem (attached).

The trace, to my untrained eye, does not seem to reveal anything  
particular other than the involvement of a few libraries other than  
the feedvalidator itself.


My suspicion of a library incompatibility is further justified by the  
fact that my test service, running the exact same code for the  
feedvalidator but on an unstable debian distribution, returns  
(almost) correct validation results.

(check by going to http://qa-dev.w3.org/feed/ and reproducing steps  
2, 3)

Any idea what could be causing this issue? I believe that the "direct  
input" validation, however flawed (the document location and most  
relative links obviously get screwed), is useful, and I'd like to  
continue providing it.

Thanks.
-- 
olivier