We have a branch B1, and it is still not stable yet so it is not in trunk. But we want to work with changes from B1 so we create a branch B2 from B1.
So svn copy was done as follows
svn copy http://svn/trunk http://svn/B1
svn copy http://svn/B1 http://svn/B2
After some days, B1 will be stable and B1 will be reintegrated to trunk.
Now, the problem lies with merging back of B2 to trunk. Do we reintegrate B2 back to B1 and then reintegrate to trunk or directly reintegrate B1->trunk and B2->trunk?