Item12843: Renaming a topic results in broken links sometimes

This is a weird one and I'm not sure it is caused by this extension - it's just a guess. Please re-categorize as needed.

The problem I'm seeing - and I've reproduced it both on my 1.1.9 site and Michael's demo site but not on foswiki.org - is that sometimes when I rename a topic it doesn't find all the links to that topic and rename them.

Here are the steps I used to reproduce this:

1. Create a topic - for example TestTopic70
2. Inside TestTopic70 type the text "TestTopic71" and save.
3. Click on the TestTopic71 link to create a new TestTopic71 topic in the same web.
4. Save the new TestTopic71 topic.
5. Move/Rename TestTopic71 to TestTopic72

Expected behavior:

• TestTopic70 should be listed on the move/rename page in the list of pages to be updated with the new link, and when you confirm the rename that page should be updated to with a link to TestTopic72.

Actual behavior:

• (sometimes) TestTopic70 is not listed as a page with links to be updated, and if you go ahead with the rename and then view TestTopic70 you'll see the link to TestTopic71 is still there but is now broken since TestTopic71 has been renamed to TestTopic72.

As mentioned, I've reproduced this numerous times on both my Foswiki 1.1.9 site and Michael's demo site. I might do this 5 times in a row, but then I go back and repeat the same set of steps again and it doesn't happen the next 5 times in a row.

I consider this problem to be fairly serious because it results in broken links.

-- LeilaPearson - 03 Apr 2014

Did some digging. Reclassifying this a SolrPlugin issue since it is using SOLRSEARCH to find the outgoing links.

I think I've figured out the cause and also why it isn't 100% reproducible.

In SolrPlugin/Index.pm the _addLink function will not add an outgoing link to a topic's search index info if the destination topic doesn't exist. The problem is the topic may be created later and when it is, the topics that refer to it won't have their index info updated with the now-valid link - at least not until they get reindexed for some reason.

Why isn't this 100% reproducible? I think it's because the original topic isn't indexed immediately. Sometimes it happens to get indexed after the topic it refers to is created, and other times it gets indexed before the topic it refers to is created.

-- LeilaPearson - 07 Apr 2014

Unfortunately this doesn't seem to fully fix the problem. Just created a group, used the group on on of my WebPreferences pages, and then reanmed the group. The WebPreferences page wasn't found or updated. Doing a Solr search, it seems that the WebPreferences pages aren't indexed.

-- LeilaPearson - 08 Apr 2014

So it seems that by default SolrPlugin is configured with a long list of topics to skip:

• WebRss, WebSearch, WebStatistics, WebTopicList, WebLeftBar, WebPreferences, WebSearchAdvanced, WebIndex, WebAtom, WebChanges, WebCreateNewTopic, WebNotify

Removing WebPreferences from the above list should fix the issue I was seeing with links in WebPreferences not being updated.

Revisiting the whole list with the following two questions in mind seems like a good idea:

• Is the topic likely to contain any outgoing links that should be updated when the destination topic is renamed?
• Would indexing this topic have any undesired effects?

-- LeilaPearson - 09 Apr 2014

You are absolutely right in both respects.

As far as I see _addLink could easily add non-existing topics as outgoing links as well.

Indexing those Webxxx topics does not harm the system either besides. I'll remove them from the defaults as you supposed.

-- MichaelDaum - 24 Dec 2014

Seems to be fixed in latest release.

-- Main.MichaelDaum - 18 Sep 2017

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