Last modified: 2014-04-24 17:54:09 UTC
It's currently possible to search incategory:X or -incategory:X, where X is a category name, to include or exclude results categorised in Category:X. However, this does not cover subcategories. This would obviously be useful, particularly on Commons where search is an important way to find media.
This could be a separate keyword, say incategorysub:X. We could also, in addition, extend incategory to specify recursion levels, with incategory:X defaulting to incategory:0:X (just the category specified - no recursion), and incategory:5:X meaning that we want to traverse 5 levels deep, and perhaps incategory:-1:X meaning the same as incategorysub:X.
Obviously, the usefulness of this feature would be enhanced by also addressing Bug 21988 (basically, providing GUI access to advanced search features).
Well it's been a year. Is there any sign of ... anything?
If you ever tried to code a similar function, you will understand the flexible structure of mediawiki category makes it difficulty to implement.
One category can have multiple subcategories, and there may have a loop in a category tree(subsubsubcategory of a parent category may be the parent category).
As long as categories of mediawiki remain flexible, I belive this function will not be implemented in the near future.
Moving this feature request to CirrusSearch queue to be reassessed at a future date.
See also https://commons.wikimedia.org/wiki/Help:FastCCI which can do this (implemented as a separate program)
*** Bug 54643 has been marked as a duplicate of this bug. ***