It may be that I'm simply misunderstanding something, but what is the rationale for having tagged() also match normal wikilinks?

It simply hasn't been implemented yet -- see the answer in tag pagespec function. Tags and wikilinks share the same underlying implementation, although ab reasonable expectation is that they are kept separate. --Ivan Z.

The following situation. I have tagbase => 'tag'. On some pages, scattered over the whole wiki, I use [[!tag open_issue_gdb]] to declare that this page contains information about an open issue with GDB. Then, I have a page /tag/open_issues_gdb.mdwn that essentially contains [[!map pages="tagged(open_issue_gdb)"]]. So far, so good: this page indeed does list all pages that are tagged like this. But now, when I add in /gdb.mdwn a link to this page, like [[Open Issues|tag/open_issue_gdb]], then /gdb.mdwn itself shows up in the map on tag/open_issues_gdb.mdwn. In my understanding this is due to the wikilink being equal to a [[!tag ...]]. What's the rationale on this, or what am I doing wrong, and how to achieve what I want?

--tschwinge

What you are doing "wrong" is putting non-tag pages (i.e. /tag/open_issues_gdb.mdwn) under your tagbase. The rationale for implementing tag as it has been, I think, is one of simplicity and conciseness. -- Jon

No, he has no pages under tagbase that aren't tags. This bug is valid. matching different kinds of links is probably how it will eventually be solved. --Joey

Done: tagged no longer matches other wikilinks. --smcv

And this is an illustration why a clean work-around (without changing the software) is not possible: while thinking about matching different kinds of links, I thought one could work around the problem by simply explicitly including the kind of the relation into the link target (like the tagbase in tags), and by having a separate page without the "tagbase" to link to when one wants simply to refer to the tag without tagging. But this won't work: one has to at least once refer to the real tag page if one wants to talk about it, and this reference will count as tagging (unwanted). --Ivan Z.

But well, perhaps there is a workaround without introducing different kinds of links. One could modify the tag plugin so that it adds 2 links to a page: for tagging -- tagbase/TAG, and for navigation -- tagdescription/TAG (displayed at the bottom). Then the tagdescription/TAG page would hold whatever list one wishes (with tagged(TAG) in the pagespec), and whenever one wants to merely refer to the tag, one should link to tagdescription/TAG--this link won't count as tagging. So, tagbase/TAG would become completely auxiliary (internal) link targets for ikiwiki, the users would edit or link to only tagdescription/TAG. --Ivan Z.