brisbane: initial cut at a mergeline cache

[Matthew D. Fuller]

On Wed, Apr 01, 2009 at 03:23:46PM +1000 I heard the voice of
Ian Clatworthy, and lo! it spake thus:
> 
> Firstly, I was definitely having a grumpy day then and I apologize
> to everyone, particularly Robert, for coming across so heatedly. :-(

Email is made for grumpy days   8-}


> Maybe I spent too long using sccs, rcs and cvs and origin-based
> numbering just reflects the approach used there? :-(

AIR, that was in fact [part of] the reason behind it.


> I don't disagree that knowing when something landed is useful.  But
> in the good old days, a number like 300.3.55 also said a lot about
> what was *not* in that revision

On the other hand, the reality of snapshottage aside, revisions
(particularly non-very-recent revisions) aren't generally thought of
for what they _contain_, so much as what they changed relative to
their parent.  So, I assign less weight to knowing what it lacks.


> My broader point was that we ought to have a UI-based reason for
> changing the numbering scheme, if we're going to.

I very much agree that making changes from a "proper" to a less so
thing just because we can't (or haven't) made it perform well is a
step in the wrong direction.

Still, my reasons were UI based from the get-go.  Here's another one:
if you think of those non-mainline revisions as being "sub-revs", as
the UI tends to present them, having them numbered as if they were
"parts" of the mainline rev they came in as makes perfect sense.


Numbering from the merge point may convey "less" information about the
rev, but I just don't think it's information that you [generic]
usefully gather by mind from that number.  A UI like log or
graph-ancestroy or a graphical viewer is a lot better for
investigating and picturing the ancestral twisting and twining.  The
information merge-point numbering gives, IMO, is information that much
more useful in the times where the dotted revno is more than an opaque
string.


> FWIW, I'm going to add the mergeline cache to a plugin.

Excellent.  Having options is always good.


-- 
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.