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 backlinks in 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.
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.
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.