Insights from bzr newbie coming from git

[Matthew D. Fuller]

On Thu, Nov 30, 2006 at 02:44:31PM +0100 I heard the voice of
David Allouche, and lo! it spake thus:
> 
> Multi-heads would make it possible to combine the efficiency of
> switch with the simplicity of standalone branches.

Having the ability to have multiple heads on one branch (as opposed to
the slightly different case of multiple heads treated fully as
different branches) allows other stuff too.  Monotone does that, and
it opens up the door to <http://venge.net/monotone/wiki/DaggyFixes>.

    This is the common established practice in traditional sequential
    VCSs, in part because in those systems, branching and merging
    aren't lightweight enough to be worthwhile using for a small fix.

Any sort of branching that requires explicitly setting up a new branch
and making the change in it, then moving over to your main branch and
re-merging, is still pretty heavyweight for that sort of thing.  But
having multiple heads on one branch, you can easily just flip back to
the right rev, make the change, then merge the heads[0].


> That's definitely a problem. Many newbies I interact with quickly
> want to go past the simple standalone branch setup, and then they
> hit a frustrating hump in the learning curve.
> 
> It is not clear whether this is a primary issue, or just fallout
> from lacking multi-heads. Any opinion?

Several paths.  One path is the git-ish "one working tree, N branches,
switch between them".  Another is the almost-bzr-ish "N branches in a
repo, one lightweight checkout, switch between them".  There's a
slight difference.


In all my years of using CVS and trying to get other people to use it,
one of the biggest conceptual stumbling blocks was always getting them
to understand "this is a _repository_, this is a _checkout_", and why
they need both.  It took ages for most people to Get It, and after
they did, most of them still cited it as something they "hated".
Completely boggled my mind.  Heck, the distinction always seem
blindingly obvious to me.  And I used RCS which _didn't_ have a
seperate location for the repository, and talk about "hate"...

Having used bzr for a while now...  well, I still don't understand why
it's such a hard concept for people to understand.  But I get how
annoying it can be.  I still like it in some ways, but I can sure see
the irritating side of it.  For instance, last night on IRC, walking
ryanakca through a SVN-style setup, I kept finding myself thinking
"This is stupid.  Why are we setting up this whole seperate repo over
there, instead of just having it all in the tree here?"


There's a lot of simplicity in the git model; all your data is RIGHT
HERE, just like a bzr standalone branch, except with a working tree
you can flip to whatever branch you want, including one you create on
the fly.  OTOH, there's a lot of capability in having independent
branches with integral working trees sitting next to each other you
can work with.  I would worry about how the two capabilities would
interact with each other.  I mean, if you have a "standalone branch"
with 5 branches at foo/, and you "bzr branch foo bzr", what happens?



-- 
Matthew Fuller     (MF4839)   |  fullermd at over-yonder.net
Systems/Network Administrator |  http://www.over-yonder.net/~fullermd/
           On the Internet, nobody can hear you scream.