Proposal: inherit group

[Matt Mackall]

Currently, Mercurial inherits file permission bits from .hg/store. This
lets newly-created files in a repo on a shared filesystem get
group-compatible permissions regardless of the current umask of the
user.

Unfortunately, the group attached to the file will not automatically be
a useful one unless all the directories in .hg/store are also carefully
marked g+s so that newly-created files and directories get shared with
the appropriate group. This, being a bit outside Unix Permissions 101,
is apparently not something most people know how to do.

So it might significantly ease things if we tried to automatically copy
the group from the .hg/store directory to newly created files and
directories in the store.

-- 
Mathematics is the supreme nostalgia of our time.