* Has bugs updating things if the bestlink of a page changes due to
adding/removing a page. For example, if Foo/Bar links to "Baz", which is
Foo/Baz, and Foo/Bar/Baz gets added, it will update the links in Foo/Bar
- to point to it, but will forget to update the linkbacks in Foo/Baz.
+ to point to it, but will forget to update the backlinks in Foo/Baz.
-* And if Foo/Bar/Baz is then removed, it forgets to update Foo/Bar to link
- back to Foo/Baz.
+ The buggy code is in `refresh()`, when it determines what
+ links, on what pages, have changed. It only looks at
+ changed/added/deleted pages when doing this. But when Foo/Bar/Baz
+ is added, Foo/Bar is not changed -- so the change it its
+ backlinks is not noticed.
-As of 1.33, this is still true. The buggy code is the %linkchanged
-calculation in refresh(), which doesn't detect that the link has changed in
-this case.
+ To fix this, it needs to consider, when rebuilding Foo/Bar for the changed
+ links, what oldlinks Foo/Bar had. If one of the oldlinks linked to
+ Foo/Baz, and not links to Foo/Bar/Baz, it could then rebuild Foo/Baz.
-Still true in 1.43 although the code is much different now..
+ Problem is that in order to do that, it needs to be able to tell that
+ the oldlinks linked to Foo/Baz. Which would mean either calculating
+ all links before the scan phase, or keeping a copy of the backlinks
+ from the last build, and using that. The first option would be a lot
+ of work for this minor issue.. it might be less expensive to just rebuild
+ *all* pages that Foo/Bar links to.
+
+ Keeping a copy of the backlinks has some merit. It could also be
+ incrementally updated.
+
+ This old bug still exists as of 031d1bf5046ab77c796477a19967e7c0c512c417.
+
+* And if Foo/Bar/Baz is then removed, Foo/Bar gets a broken link,
+ instead of changing back to linking to Foo/Baz.
+
+ This part was finally fixed by commit
+ f1ddf4bd98821a597d8fa1532092f09d3d9b5483.