Merge branch 'master' into dependency-types

Conflicts:
	doc/todo/dependency_types.mdwn

diff --combined doc/todo/dependency_types.mdwn
index 19294bba054e5fb509c97a23de6c6a1f8cc267eb,7e940543c00aa248c018d4f6c30a5131162eec66..32c9187be27ef07135a8a3300c5bafb8c657151c
--- 1/doc/todo/dependency_types.mdwn
--- 2/doc/todo/dependency_types.mdwn
+++ b/doc/todo/dependency_types.mdwn
@@@ -158,11 -158,14 +158,11 @@@ pagecounts much more efficient
  
  ---- 
  
- Link dependencies:
+ ### Link dependencies
  
  * `add_depends($page, $spec, links => 1, presence => 1)`
    adds a links + presence dependency.
 -* `refresh` only rebuilds a page with a links dependency if
 -  pages matched by the pagespec gain or lose links. (What the link
 -  actually points to may change independent of this, due to changes
 -  elsewhere, without it firing.)
 +* Use backlinks change code to detect changes to link dependencies too.
  * So, brokenlinks can fire whenever any links in any of the
    pages it's tracking change, or when pages are added or
    removed.
@@@ -172,4 -175,32 +172,33 @@@
    that the page links to, which is just what link dependencies are
    triggered on.
  
 +[[done]]
+ ----
+ 
+ ### the removal problem
+ 
+ So far I have not addressed fixing the removal problem (which Will
+ discusses above).
+ 
+ Summary of problem: A has a dependency on a pagespec such as
+ "bugs/* and !link(done)". B currently matches. Then B is updated,
+ in a way that makes A's dependency not match it (ie, it links to done).
+ Now A is not updated, because ikiwiki does not realize that it
+ depended on B before.
+ 
+ This was worked around to fix [[bugs/inline_page_not_updated_on_removal]]
+ by inline and map adding explicit dependencies on each page that appears
+ on them. Then a change to B triggers the explicit dep. While this works,
+ it's 1) ugly 2) probably not implemented by all plugins that could
+ be affected by this problem (ie, linkmap) and 3) is most of the reason why
+ we grew the complication of `depends_simple`.
+ 
+ One way to fix this is to include with each dependency, a list of pages
+ that currently match it. If the list changes, the dependency is triggered.
+ 
+ Should be doable, but seems to involve a more work than
+ currently. Consider that a dependency on "bugs/*" currently
+ is triggered by just checking until *one* page is found to match it.
+ But to store the list, *every* page would have to be tried against it.
+ Unless the list can somehow be intelligently updated, looking at only the
+ changed pages.