Extension:QrCode/Impersonation

= Problem Description =

Editing a page and uploading a file (thus creating a new page) at the same time causes the parser object that was responsible for editing the page to be replaced by the new file's parser object after its upload. Thus all the linking happens on the file and not the page and the page displays the file's title.

1. QrCodes are generated for pages that do not have or transclude a function call, in this case properties [2,3,4].

2. These uploaded files have properties [5] and they belong to a category, which means they get linked in the categorylinks table. A common result of this is that qrcode images turn up in i.e. semantic queries [9,10].

3. Qrcodes are even generated for existing qrcodes [6,7]. One way to trigger than behaviour is to visit a File's page and click on the Delete link, without actually deleting the file. This leads to situations such as [8].

4. The files get linked from several pages as this example shows [11]. None of the pages said to link to the file actually do include that file, also those pages vary (2 days ago, 14 pages linked, today only 7 link)

5. Browsing the properties of the above file [12], you can see that it got somehow mixed up with a completely different event.

[0] http://www.mediawiki.org/wiki/Extension:QrCode [1] http://svn.wikimedia.org/doc/classLocalFile.html#4b626952ae0390a7fa453a4bfece8252 [2] https://www.hackerspace.lu/wiki/File:QR-Is_U19.png [3] https://www.hackerspace.lu/wiki/File:QR-Has_SingleIssuePrice.png [4] https://www.hackerspace.lu/wiki/File:QR-Has_Issues.png [5] https://www.hackerspace.lu/wiki/Property:Has_SingleIssuePrice [6] https://www.hackerspace.lu/wiki/File:QR-QR-Location.png.png [7] https://www.hackerspace.lu/w/index.php?title=Special:RecentChanges&hidebots=0 [8] https://www.hackerspace.lu/wiki/File:QR-QR-QR-QR-Location.png.png.png.png [9] https://www.hackerspace.lu/wiki/Projects#Concluded_Projects [10] https://www.hackerspace.lu/wiki/Special:BrowseData#Q [11] https://www.hackerspace.lu/wiki/File:QR-Syn2cat.png [12] https://www.hackerspace.lu/wiki/Special:Browse/File:QR-2DSyn2cat.png

= possible causes = It's possible that the internal uploading process interferes with global parsing state when it generates and saves the description page for the wiki; if so, fixing that may require jumping through some interesting hoops. :)

-- brion