Available in a git repository branch.
Branch: GiuseppeBilotta/scanif
Author: GiuseppeBilotta

When a directive that should be run during scan preprocessing is inside an if directive, it doesn't get called because the if preprocessing does not run during scan.

I've written a simple patch to fix the issue, currently hosted on the scanif branch of my repository. The patch also passes the preview option back to the Ikiwiki::preprocess call, making sure that whatever is being reprocessed is done so in the same conditions as the original call.

One problem with this is that it has the same dependency-ordering problems as inline-based or pagespec-based trails with my ?trail plugin: if takes a pagespec, but pagespecs aren't guaranteed to match correctly until everything has been scanned (for instance, link() might give the wrong results because a page that added or deleted a link hasn't been scanned yet). If you have a clever idea for how to fix this, I'd love to hear it - being able to specify a ?trail in terms of a sorted pagespec would be useful. --smcv

I have a solution to the dependency-ordering problem in a different branch of my repository, with a post_scan hook mechanism which I use to be able to sort outer inline pages according to the last modification date of their nested inline pages. The way I implemented it currently, though, doesn't use the existing hooks mechanism of ikiwiki (because it's something which I believe to be more efficiently done the way I implemented it) so I don't know how likely it is to be included upstream.

For what it's worth, I think that my post_scan hook mechanism would work rather fine with your trail plugin.

We discussed this on IRC, and I think it's actually more complicated than that: the branch to sort by newest inlined entry wants a "pagespecs now work" hook, whereas for trail I want a "sorting now works" hook:

• scan
• pagespecs now work (post-scan)
  • Giuseppe's version of inline can decide what each inline contains, and thus decide where they go in inline(mtime) order
• pagespecs and sorting now work (pre-render)
  • my trail plugin can decide what each trail contains, and also sort them in the right order (which might be inline(mtime), so might be undefined until pagespecs work)
• render

--smcv

However, the case of the if directive is considerably more complicated, because the conditional can introduce a much stronger feedback effect in the pre/post scanning dependency. In fact, it's probably possible to build a couple of pages with vicious conditional dependency circles that would break/unbreak depending on which pass we are in. And I believe this is an intrinsic limitation of the system, which cannot be solved at all.