very sorry, my finger slipped onto the over-sized "Enter" button on this funky keyboard. tried to cancel but it was too late.
Intended message follows:
As Simetrical explained: "linktrail characters should be those that should *always* be included in the trail." http://lists.wikimedia.org/pipermail/wikitech-l/2008-June/038326.html
I don't think a feature intended for easy creation of plural links (or for changing nouns into verbs, adjectives, etc by adding a few extra letters) should automatically create potentially confusing possessive forms ("[[Foobar]]'s", etc.)
If I wanted [[Foobar]]'s to look like [[Foobar's]] I'd pipe it manually as [[Foobar|Foobar's]] but this would be a rare case in itself (like a restaurant named after a person, where only the person has an article, maybe??? but even that would be on the outer edge of likelihood).
moreover if this is not fixed would I have to do some ugly code like [[Foobar]]<span/>'s to keep the "apostrophe ess" from being sucked into the link, or is there a better way?
I agree with Charlotte, on reflection. This is a bad change. The target of the link should be described by the link text if not specifically overridden. If I write [[spider]]s, then including the "s" would be correct, because the [[spider]] article is indeed about "spiders". If I write [[spider]]ing, then the [[spider]] article would indeed be about "spidering", since that's what spiders do. (Yes, it's a stupid example; pretend [[spider]] is about web spiders or something.) But if I write [[spider]]'s, the [[spider]] article is not about "spider's". Indeed, having an article about a possessive is silly, unless it's about the word itself or a proper noun, and in that case the title of the article should be [[spider's]] to begin with.
CC'ing Dantman, since he introduced this change.
I don't understand the logic of your example, Simetrical. "X is about Y" sentences turn ungrammatical if you use genitives for Y, but I don't see the point, why linking the word turns bad cause of this. The purpose of linktrails is not, that the linked article should be about the whole word, but cause words linked only partially are "ugly". It's "style guide" reasons, not semantic ones. And genitive suffixes are part of words just like plural suffixes are.
Perhaps someone could start a discussion on mediawiki-l to discuss the usefulness of including 's vs. excluding it.
Then we could get feedback from more than just a select few devs and a user or two. This is something I've heard complaints on that [[Foo]]'s is not linked in the past. So perhaps a wide group discussion would be best for determining. But the main complaint I hear is that [[Foo|Foo's]] when linking 's is correct is quite ugly and most wiki like to avoid doing unnecessary things like that.