Cannot merge bundles created without referencing another branch.

[Harald Meland]

[Anton Dedov]

> So I need  make  branches, that I receive and construct from a students'
> bundles, available via network in order they could use "send" without -r
> option?

The "send" command, when called without any -r option, will try to
access your current branch's "parent branch" to determin which
revisions need to be sent.  However, the "parent branch" does not need
to be available via network -- it just needs to be available.  One
possible workflow would be:

 1. Student sets up a repository (with trees, for simplicity):
    bzr init-repo ~/studies

 2. Student creates a local branch for their initial submission:
    cd ~/studies
    bzr branch http://tutor.host/path/to/base/branch/of/assignment \
      assignment.base

 3. Student creates a branch for the work they'll do before the first
    submission of their branch:
    bzr branch assignment.base assignment.submission-1

 4. Student works on the code towards first assignmment:
    <hack hack hack>
    bzr add
    bzr commit "Ready for first submission to tutor"

 5. Bundle for first submission is created:
    bzr send

 6. If the tutor isn't happy, the student creates branch for their
    second submission:
    bzr branch assignment.submission-1 assignment.submission-2

 7. Repeat 4-6 until tutor is happy.

Alternatively, if you'd like to avoid having to teach the students
this workflow, you could continue receiving submissions as .tgz files,
and implement a similar workflow for yourself by using "bzr import".
-- 
Harald