We sometimes need to know whether we are in a wiki's revisions/archive subfolder, or in the main wiki folder. Eg when viewing or doing other things with a page revision object. Here are some alternatives I've considered:

  1. use known folder ids like 'revisions' or 'archive - this means your wiki will break if you happen to choose that id for the wiki folder. This is what we've done up to now, and I just noticed the bug.
  2. use ids, but more obscure ones like 'zwiki_revisions' or 'revisions_' - old wikis will break and need (quick) upgrading; urls are not as nice
  3. use a custom folder type - old wikis will break and need upgrading; custom types in the zodb are a pain with their ingrained module paths
  4. use folders with a marker attribute added - old wikis will break and need (quick) upgrading; folders that look normal but aren't seems like fertile ground for gotchas (but, when would you ever manually create an archive/revisions folder; and copy/pasting a wiki should still work)

For now we stick with 1. We could detect and warn in the failure mode, but we don't yet.