At first I wasn't sure if a question on how to do something advanced in MediaWiki belonged here, but upon reading the faq and thinking about it, I decided that wiki markup is as much its own language as HTML and CSS, and if those questions are welcome here, then hopefully this is too! If I am wrong feel free to flag this question. Update: Well as evidenced by the 3 views this question got, I suppose that while perhaps it's within the rules of Stackoverflow, there might not be much expertise on the subject! I suppose I will need to take this question to the official forums (shudder)
The problem
On a wiki I am setting up powered my MediaWiki, I have a Template that outputs among other things dynamically created categories. This means that the page that invokes the template will be categorized based on some of the variables passed to the template. The dynamically generated categories are inside <includeonly> blocks to prevent the template page itself from getting the categories.
The problem is that I then transclude that page on to other pages, which causes the categories to be transcluded as well, and now that third page has all of the categories of all of the pages it transcluded.
I want to somehow format the template such that the page that invokes the template will make use of the categories but any pages that transclude the invoking page will not inherit the categories.
Example
Here's my best shot at an example of the setup. If this is inadequate I can provide links to my real-world example.
Template:Food
A page that takes a couple variables and outputs a highly formatted block that explains the food, including outputting a category based on the "type" variable.
Banana
This page invokes the Template:Food template with a few variables, including type set to "fruit". The result is when the user views the "Banana" page they get a nicely formatted page with some basic information about the fruit. Furthermore, if the user goes to the Category:Fruit page, they will see the Banana page listed.
Banana Nut Bread Recipe
This is the problem page. On this recipe page, the author wants to transclude all of the pages for ingredients so that each ingredient is listed in its nicely formatted block. However, when he transcludes the Banana page using {{:Banana}}, the Fruit category is transcluded along with it and now the Banana Nut Bread Recipe page is listed as being in the Fruit category which is wrong.