Last modified: 2005-08-20 15:46:16 UTC
Certain parts of the code, notably "transclusion", use a leading colon to indicate the main namespace, since they would otherwise refer to something else. e.g. {{Foo}} transcludes the content of "Template:Foo"; {{:Foo}} transcludes the content of "Foo" The check for this initial colon is inside Title::secureAndSplit(), and before the namespace recognition function; only a dodgy detection of ":Image:" (which doesn't take account of canonical names for namespaces, and is anyway unnecessary since the Title object doesn't need to know about this, Parser.php deals with it, along with similar cases such as ":Category:") is performed before it. Thus, a title which also has a real namespace will produce an illegal Title object (namespace 0, but named e.g. "Project:About") On [[meta:]] {{Project:About}} and {{Meta:About}} both work correctly. {{:Meta:About}} renders as either a red (edit) link, a blue (normal local) link, or a correct transclusion, depending what other related transclusions appear on the page; {{:Project:About}} seems similar, but I haven't managed to get it to transclude correctly, only display as a red or blue link. There seems to be some odd effect of ¿caching?, since "{{:Meta:About}} {{Meta:About}}" produces two redlinks, whereas "{{Meta:About}} {{:Meta:About}}" produces two transclusions. The check in Title.php can be moved to *after* other namespace recognition (by first removing the : but setting a variable if we do so), but there may be other bugs in transclusion that this bug reveals. Also, is there anywhere other than Parser::replaceInternalLinks() which needs to 'know about' ":Image:", ":Category:" et al?
I've committed a fix to this in both HEAD and 1.5, such that Titles with a leading colon still get examined to see if there's a namespace in there - Titles with {ns, title} like {0, Project:Foo} should never exist.
