Change the file-id of the root

[James Westby]

Hi,

rich-root by default has exposed an existing bug in bzr-builddeb.

We want to create two trees that share no revision history, but which
share the same root id, as we expect to merge them later.

We get this for free with non-rich-root obviously, but with rich-root
it is harder to do as a random id is assigned when the tree is
created.

My question is, what is the best way to achieve this? There doesn't
seem to be an interface to change the id of the root, so I am guessing
the best way is to somehow initialise the tree from the other. Is there
a way to do a "branch" operation that uses the file-id for the root,
but leaves the new branch with an empty history?

Thanks,

James