Importing vendor sources into a branch

[Theo Markettos]

I have a project in CVS which consists of three branches.  Because I
ultimately don't know which branch is going to be successful (they a bit
like prototypes, except share much code) none of these is the main trunk,
which lying unused.  Development is currently happening on only one branch,
but might switch to another branch if that is a better target for it.

I now want to import a large body of files to be a subdirectory of one of
the branches.  This is a vendor supplied tree, which is most likely going to
need updating at some point in the future - so I need to do an import of
third-party sources.  I can do this with

cvs import myproject/subdirectory <vendor> <release>

but AIUI this imports it for any checkout to see.  So I can check out
another branch and this subtree will appear in it - whereas I want it to
only appear in the one branch that I'm working on.  This makes it look like
I need cvs add, but then can I update from new vendor sources?

Also how does CVS cope with import of a new third-party source tree into a
project that has branches?  My main sources are based on a third-party tree
which I wish to update with new vendor supplied sources.  However there has
been significant modification in both my tree and the vendor sources.  I
wish this update to affect all branches of the tree - must I use 
cvs admin -b to promote each branch to head before I import the tree three
times? Does such an import affect only the head of the tree, or previous
revisions in the tree as well?

Thanks,
Theo

-- 
Theo Markettos                 address@hidden
Liphook, Hampshire, UK         address@hidden
                               http://www.markettos.org.uk/