Last modified: 2008-11-21 09:02:13 UTC
There is a magic word REVISIONTIMESTAMP, which contains something like 20081120190615. Now suppose I set the property Time Stamp to be the revision time stamp: 20081120190615. then after editing and saving the page, I again click on the edit button followed by Save page, this time without making any changes. Then I find that the Time Stamp property contains two values, which should not be the case. On the other hand, if during the last edit, a change was made, then (most of the time) the property only contains a single value, as indeed it should. In the exmple page ( http://gingerwiki.com/wiki/Property_Bug_Example ) the Time Stamp property currently contains: 20081120190643, 20081120190615 This definitely seems like a bug to me. The problem does not seem to be with the magic word REVISIONTIMESTAMP as I have found it to be consistently single valued. The problem seem to be with the current sematic property data-base. In particular after an edit and Save Page with no changes, the properties are being updated but the previous value is not deleted, and so we end up with double valued properties. I have also found that sometimes when I click edit, make some changes and then Save page, I find that the Time Stamp property contains two values, one second apart. I guess this is effectively the same bug as mentioned above.
This would indeed be a bug, but I cannot reproduce it on our current version (using the most current MediaWiki from SVN). You are running an early development prototype of SMW 1.4. Please update to the current SVN (doing this, besides installing the files, requires to press the button on Special:SMWAdmin again, there now is also a second button for refreshing all data which would be a good idea too). Please report back if the bug still occurs (I am optimistic and close this bug in the meantime; feel free to reopen it). Also note that SMW 1.4 now offers a built-in property "Modification date" that automatically holds the date of the last revision (at least after your data was refreshed for all pages). This might be helpful to achieve what you try to do here.