addrevision: rework generaldelta computation The old code have multiple explicit tests and code duplications. This makes it hard to improve the code. We rewrite the logic in a more generic way, not changing anything of the computed result. The final goal here is to eventually be able to: - factor out the default fallback case "try against 'prev'" in a single place - allow 'lazydeltabase' case to use the smarter general delta code path when the incoming base does not provide us with a good delta.

bmstore: close file in a finally block in _writerepo Also rename the variable to file_ to avoid shadowing a builtin.

bmstore: add basic clean-state tracking I'm about to move active-bookmark management into the bmstore. I'd like to avoid re-writing the bookmarks data (as distinct from the active bookmark file) if possible, so let's introduce some dirty-tracking early.

bookmarks: hoist getbkfile out of bmstore class It's totally fine that this hook exists, but I don't see a need for it to live inside the bmstore class.

bookmarks: document getbkfile method I'm working on bmstore again, and this function gave me a moment's pause. Document it to save future readers from any undue confusion.

hgweb: load server settings from --web-conf (issue4699) It copies the ui before loading the webconf and passes the copied ui only to the service. This way, the hgwebdir app can reload configs cleanly.

extdiff: correctly handle deleted subrepositories (issue3153) Previously, when extdiff was called on two changesets where a subrepository had been removed, an unexpected KeyError would be raised. Now, the missing subrepository will be ignored. This behavior mirrors the behavior in diffordiffstat from cmdutil.py line ~1138-1153. The KeyError is caught and the revision is set to None. try/catch of LookupError around matchmod.narrowmatcher and sub.status is removed, as LookupError is not raised anywhere within those methods or deeper calls.