Access control: the ability to constrain developers to operating in specific areas of the tree, implement branch-based policy restrictions, as well as to enforce policy such as tagging of commits for developers working outside their normal areas. Implementing these via hooks would not be a regression from what we currently do in CVS.

Hg is distributed and has a “a repository per branch” feature meaning that every developer has his/her own copy of the repositories he/she has an interest in as a set of private directories.

These copies can be published thus are also clone/push/pull-able.

Access control to these will be controlled by an HTTP server (the preferred way of publishing) thus will use the server way of authencating access.

For the reference trees, I'd expect the [“Patch Queue Manager”] to deal with write access.

Partially Supported

Currently hooks can be used to restrict many premissions in [“Monotone”], but a fully featured ACL system is in the works and will be available “soon”.