[MERGE/RFC] Userdoc Driven Design on the Bazaar 2.0 UI

[Matthew D. Fuller]

On Wed, Apr 15, 2009 at 05:21:05PM -0700 I heard the voice of
Maritza Mendez, and lo! it spake thus:
> 
> But I spend a lot of time explaining how checkout in bzr is
> different from checkout in central VCS.  So in this way I agree with
> Mr. Shuttleworth in that making checkouts light by default [...]

If you're explaining them in such a way that light checkouts are
easily explainable, but heavy checkouts get things bogged down, You're
Doing It Wrong(tm).

There are ways in which the two behave differently; I'm prepared (in
fact, quite willing and even eager) to define practically all of them
as bugs, many springing from heavy's tendancy to try to act like a
bound branch rather than a checkout[0].  Are you explaining that
there's a branch underneath, except it's only sorta a branch?  Stop.
Don't do that.  Talking about unbind, or commit --local?  Stuff a rag
in your mouth.

If somebody is ready and able to profit from coloring outside the
lines by exploiting side effects of heavy checkouts, they understand
what's going on under the hood well enough to figure it out
themselves.  If they don't, they aren't.


A checkout is a checkout.  Ever used CVS?  Just like that.  SVN?  Just
like that.  The only difference between heavy and light is [should be]
that one burns a bunch of local disk to cache a bunch of information
to avoid hitting the network.  That's IT.  That's ALL.  Say that one
sentence.  Then add the rule of thumb "If the branch is local,
checkout light.  If the branch is network, checkout heavy.".  You're
done explaining.



[0] Really, I've come to think this implementation path was one of our
    big mistakes.  Having the mechanism for binding branches made it
    Real Simple(tm) to implement something close enough to a checkout
    with a local cache to run with.  But having it be a "branch except
    that" instead of "not a branch except that" just leaves all sorts
    of trapdoors hanging around that are way too easy to fall into.


-- 
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.