How do you keep track of what's been merged in CVS?

[Doug Lee]

I ask this here because FreeBSD is managed by CVS...

My understanding of the FreeBSD development model is that "current" is
the CVS trunk, "stable" is a branch started at the latest release tag,
and an MFC consists of selectively merging revisions from the trunk to
the Stable branch.  If that's right, how do you keep track of what's
been merged and what hasn't, particularly when merges may not occur in
chronological, or revision number order, or (if this applies) when a
merge is edited while being merged and does not contain the full
effect of the corresponding original code?  Also, is there a way to
cause a file on a branch to track HEAD on the trunk automatically?  (I
asked that on the cvs-info list and noticed no answer

I'm learning to use CVS to manage my own (much smaller) projects, and
I'm just beginning to realize that if I don't find an answer to this
one, I'll get my head spinning pretty soon trying to keep branches up
to date with trunk activity.

Thanks much.  Please Cc replies to me if you think about it.

-- 
Doug Lee           dgl at dlee.org        http://www.dlee.org
Bartimaeus Group   doug at bartsite.com   http://www.bartsite.com
"Determine that the thing can and shall be done, and then...find
the way." - Abraham Lincoln