Lots of good +Mercurial
stuff coming out of Facebook these days! You can now get sparse checkouts (creating only part of your working copy — makes "hg status", "hg diff", etc faster) and shallow clones (download only the latest version of your files). This makes it much easier to work with gigantic repositories. There's also a push-rebase extension that does SVN-like merging (rebase, really) on the server side to avoid races on push. Sounds convenient, but it implies a non-pull request workflow.
They've also released a great hgwatchman extension that makes "hg status" instantaneous by using inotify or fsevents to listen for filesystem modifications. Most other commands also get a speed boost since they call status under the hood.
Very exciting developments! The question is now if it's too late to matter for regular developers... Given the dominance of +Git
, will Mercurial will end up being the hyper-scalable revision control system used by a few big corporations?