Trying to understand BZR repository

I use Bazaar and I love it. Generally, I just create different branches and manage them separately. I've just found that all those branches can be put into a repository. If I understand correctly, this should save memory and increase speed as some common ancestor between branches are shared. Q1: Do I understand this right? Another thing is that when I try to use it I found some problem which I really do not get it. Here is how I attempt. ``` bzr init-repo --trees TestBzrRepo cd TestBzrRepo bzr init trunk mkdir branches cd branches bzr branch ../trunk b01-Add-file2-f echo 'This is file 2' > file2.f bzr add file2.f bzr commit -m "Add file 2" cd ../../trunk echo 'This is file 1' > file1.f bzr add file1.f bzr commit -m "Add file 1" cd ../branches/b01-Add-file2-f ``` From now if I do `bzr pull ../../trunk`, I got: ``` bzr: ERROR: These branches have diverged. Use the missing command to see how. Use the merge command to reconcile them. ``` If I do `bzr merge ../../trunk`, I got: ``` bzr: ERROR: Branches have no common ancestor, and no merge base revision was specified. ``` `bzr conflicts` returns nothing and I still cannot pull or merge. What happen here? and What should I do next. Please help. Thank you in advance.