Pushing after merge considered harmful

[Stephen J. Turnbull]

Brian de Alwis writes:

 > For example, I realized reading this conversation that I have no
 > idea how the mainline is established -- what makes the left-hand
 > side on my branch different from the left-hand side of another
 > branch?

Conceptually, this branch is yours, ie the one you habitually commit
to, and that one is someone else's.  That's all there is to it, it's
no deeper than that.

Technically, it's all a matter of which .bzr is used as source and
which as target when you execute "bzr merge; bzr commit".  The tip of
the target is always the left-hand parent of the new commit.