Item10789: foswiki.org/Extensions/WebChanges can be crashed by a topic that fails to load completely

http://foswiki.org/Extensions/WebChanges will fail with a lenghty message.

-- ModAcOst - 25 May 2011

In trying to see what might be causing the issue, I was comparing bin/changes script with WebRss and WebChanges. Item8570 contained an ampersand in the Summary and had broken WebRss, After editing that topic and substituting "and", WebChanges seems to be working. I have no idea if this is actually related, and unfortunately I didn't record the traceback first. Failure was calling InfoCache with an unblessed reference.

-- GeorgeClark - 25 May 2011

Raised to urgent, if we're getting it on foswiki.org, others probably are too. I saw an error like this on trunk and found that we weren't handling bad/missing topicinfo metadata very well.

-- PaulHarvey - 26 May 2011

Found the following error repeatedly in the error_log from the 25th.

[Wed May 25 21:29:50 2011] [error] [client 62.243.208.118] [Wed May 25 21:29:50 2011] view: Deep recursion on subroutine "Foswiki::Query::Node::toString" at /usr/home/foswiki.org/public_html/lib/Foswiki/Query/Node.pm line 94., referer: http://foswiki.org/Tasks/WebChanges

However I can't correlate this with the save of this task, so may be unrelated.

-- GeorgeClark - 27 May 2011

WARNING: this is temporarily hacked on foswiki.org. refer to http://trunk.foswiki.org/Extensions/WebChanges to see the evil disease!

I can confirm that without the hack, it fails on f.o as well.

Index: InfoCache.pm
===================================================================
--- InfoCache.pm   (revision 11876)
+++ InfoCache.pm   (working copy)
@@ -325,6 +325,7 @@
             my $info = $metacache->get($webtopic);
             if ( !defined( $info->{$sortfield} ) ) {
                 if ( $sortfield eq 'modified' ) {
+$info = $info->{tom} unless UNIVERSAL::can($info, "getRevisionInfo");
                     my $ri = $info->getRevisionInfo();
                     $info->{$sortfield} = $ri->{date};
                 }

Same hack worked on t.f.o. Really needs Sven to look at this, as he understands InfoCache.

-- CrawfordCurrie - 08 Jun 2011

thankyou for the hack diff here.

I am looking into this, though only as I find brain time - InfoCache was written by a crazy person, and every time i touch it, weird things happen :/

-- SvenDowideit - 09 Jun 2011

really fascinating. - its still only the VarNEXUSTREES topic - so I need to make a unit test that mimics that case.

-- SvenDowideit - 09 Jun 2011

fixed in 1.1 - i think.

-- SvenDowideit - 12 Jun 2011

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