I've made some changes promoting better coding patterns in some contexts.
These are for MediaWiki 1.18, extensions can keep their old patterns till they drop support for pre-1.18. I'd like to consider dropping the rewriting of $wgTitle and $wgOut inside of SpecialPage::capturePath around MediaWiki 1.20. This means that after that release includable special pages in extensions will have to use the new patterns instead of relying on the $wg replacement hack.
When working on special pages (ESPECIALLY includable special pages): - Use $this->getOutput() instead of the $wgOut global. - Use $this->getUser() instead of the $wgUser global. - Use $this->getSkin() instead of using $wgUser->getSkin();
In contexts where you are working with $wgOut or another OutputPage instance and using $wgUser and skin instances fetched from it to render stuff being passed back to output: - Use $out->getUser() instead of the $wgUser gobal. - Use $out->getSkin() instead of using $wgUser->getSkin();
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I have some thought to go through on what to do about the Linker in some contexts, but I have some plans I'm thinking of regarding Skin: - I'm thinking of making $out->getSkin(); the primary point for getting a skin instead of $wgUser->getSkin(); (I'll still keep BC), making OutputPage the focal point for things related to the output of the page. Having OutputPage track and manage skins also avoids some special case bugs, it's actually more sane for OutputPage to manage the skin when you examine various branches of code. - Along with making OutputPage track the skin I'm planning on dropping support for getSkin( $t ); examining the code it's not actually even used, and the only code using it actually shouldn't be playing with a full skin at all anyways, and making Skin defer to OutputPage for most of it's title information. Instead of having 3 near-global copies of the Title floating around ($wgTitle, $wgOut->mTitle, $wgUser->getSkin()->mTitle).
I haven't decided what do about the linker yet. But I'm considering making the Parser get it's linker via $po->getLinker(); (either ParserOutput or ParserOptions, I need another look) and getting a plain linker instance instead of a skin. Skin will define a getLinker() which will replace it's subclassing of Linker (there will be some bc). To allow for the overloading of parts of the linker, which was sorta possible already, but making it more reliable, getLinker would be overridable by a skin that wanted to make linker changes so it could return a subclass of the linker. The getLinker in Parser context will take that into account, if a subclass of Linker is being used instead of the normal linker the parsercache key will change, as a result we will both make overriding linker methods reliable and usable, while also avoiding any unnecessary parser cache fragmentation which would happen if we went and included the skin name into the pcache key.