> Wow, you're really not willing to concede a single point, ever, are  
> you?

Hi Josh,

You are really not understanding my point. So I didn't concede your  
point, because your point seemed to me to be being scored against the  
wrong target.

You appear to be attempting to point score on the relative technical  
merits and possible uses of individual scm tools. Whereas I was  
attempting some abstract thinking about the process here, and the  
actual tools are not that relevant.

You appear to repeat the same mistake when you have a go at "bob", bob  
is only a hacked together second attempt at a concrete tool for  
attempting to implement an abstract idea, a new way of working and  
thinking about the problem, in other words a different paradigm.  You  
attack the tool and its implementer, on its lack of technical merits,  
and my inadequate capabilities, without understanding the value of the  
abstract thinking behind it. The deliverable of bob, is the  
demonstration and framework that allows you to think using the new  
paradigm, not fundamentally the tool itself. You say to me, ah ha,  
Lukas has developed a new CI tool, which is better than yours, so its  
ok we can ignore you, throwing bob away is justified. But, Lukas is  
using his new tool simply as a way of automating the old paradigm.  
Conceptually, you load an image from scratch, load some packages and  
test them, this is how Lukas is using his tool. You can do this  
manually, there is no new paradigm demonstrated here.

Lets try again once more.

1.

Conceptually, there is one Seaside3 repository held centrally, and one  
team developing it, and there is one Seaside3 Head, for the entire  
world. This is the essence of the centralised approach. (Of course,  
anyone can do what they want locally) Linux may use distributed tools,  
but conceptually it is being controlled by one individual Linus, so it  
is also fundamentally a centralised model of thinking, no matter what  
the tools are able to achieve in practice.

Your point that Monticello can work in a distributed fashion is fine,  
of course it can, but in practice, it isn't used that way. There is  
only one head for Seaside3, and there is only one head for Linux,  
since effectively the Linux kernel is only one product with one gate  
keeper, and there is only one head for "trunk" too.

Fundamentally 3 years ago a small group of us recognised that  
innovating new features on just "one head" was a thing of the past for  
squeak, we already have 8 or more maintained forks of varying  
descriptions. That's what the pharo guys were doing too just  
innovating for themselves, and with every commit pharo was making it  
harder to maintain packages in common with squeak. The pharo team's  
response to this dilemma was to say "we dont care", the squeak team  
and the boards response to this dilemma 3 years ago was to say "we do  
care". We will write tools that fundamentally expect to fix, innovate  
and test against multiple forks. We can let pharo be the hare, but we  
can win in the long haul as the tortoise, because our innovations will  
be more carefully implemented and tested, and will be more useful to  
more people with existing code bases to support.

So as I was saying, it is an abstract point, that conceptually the way  
we think when we do development, is basically to swarm around a  
centralised resource, be it a repository, an image or a person. When  
we do this, we are signing up to depend on that resource for the  
longer term.

2.

Along comes Mercurial, a new kid on the block with a new fundamental  
concept.

They put forward a different abstract idea fundamentally. When you use  
mercurial, every checkout/branch is a head, and is equal at every  
level and is indistinguishable from the original (In fact unlike, git  
and bzr, mercurial, only really supports any notion of centralised  
repositories, and a lightweight checkout because some users demanded  
it for pragmatic reasons)

With mercurial when you branch, you get everything. Your "head" is  
equal to and as good as anyone elses, and you could take your work to  
the moon, and forget the rest of the world exists, forever.

The equivalent in the squeak world is that when I branch to develop  
something on top of seaside3, I get the whole of the seaside  
repository to take with me, and I get my own seaside3 head. I can now  
make innovations to seaside locally, and I can provide a new seaside  
head to the world if I want to.

Now that is a silly idea isnt it, I hear you think, what would the  
world want with, and what is the use of, 15 different heads to a  
product that is obviously being developed by one team.

However, if you read the documentation, the Mercurial guys then  
recommend an entirely new approach to working. What you do, is you  
make a separate branch relative to a fixed point (A), (a release for  
example) for each new feature or bug fix, (B, C and D), (or developer  
working on a feature) in your product. This ensures that each feature  
may be tested and developed by itself, relative to a known starting  
point, the branch ancestor.

The result being that you locally get all the little deltas of each  
little change (B.1->B.2->B.3) you make when developing that feature,  
but when you come to publish, you also have one big delta (B.3 - A)  
for the whole feature. That big delta for that feature is not  
contaminated with the work on other features.

So, when the time comes to make a release you make a new fresh branch  
(A.2) from the old fixed point (A), you pull from each of the  
innovations in turn and merge them in (A.2 = A + (B3.-A)+(C.3-A)+(D3- 
A)), (this is the opposite of the above 1, in which the innovators all  
effectively push to a central repo. or gatekeeper). In addition, you  
don't then automatically require the developer of that new feature to  
continue his work from your new head (AA). He can continue to produce  
B.4 B.5 and B.6, so that when you merge in his work again. You merge  
(A3= A.2 + B.6-B.3).

Are you getting the point that the mercurial approach is a different  
paradigm, it is fundamentally distributed.  (even though technically  
you can use it in a centralised manner)

So... I was suggesting that with Cuis, we could switch from a mindset  
that thinks centrally, to a mindset that thinks distributed.

At present there is conceptually one head for the world for  
everything, i.e. Squeak3.10 + 700 packages in squeak map.

My thought was that when you download a distribution built on cuis,  
you conceptually get all 700 packages, and all their history. When you  
work you adapt everything you need to work for cuis, and you ignore  
the rest of world. You could in fact over a very long weekend delete  
FileDirectory and port every single package to something better.

Then when you publish your result, it becomes a brand new distribution  
"Sooty", equal in status to the first, each of the packages you load  
is fully manageable in the context that it is being used. Others  
interested in your innovations can study them in context, and pull  
them as they desire.

3.

When you tell me that my bob process relying on Mantis is no good, as  
many have attempted to do. This criticism is based upon point scoring  
because they dont think that technically these tools would do it as  
well as they would like. Basically saying imho "mantis is crap so  
anything that uses mantis will also be crap", by definition.

What you fail to understand is that my bob process is not built on  
mantis, it is built on the abstract principle, that you start with a  
known fixed point and develop each innovation as a separate delta.

Then you can apply those deltas individually to several forks. If for  
some reason a delta doesn't work in a fork, then the fork can be fixed  
to address the problem. Fixing the fork actually results in all the  
forks converging to be closer to the original fixed point, and some  
essential commonality is preserved. Every innovation that you make for  
just your own image, that you do not make available for other forks to  
try, is potentially destroying commonality. Every innovation and patch  
that you make available for other forks to try is potentially  
improving commonality.

Mantis just happens to be the place where the fixes are at the moment.  
Several developers all innovate relative to that known fixed point.  
Bug fixers develop bug fixes relative to that known fixed point, and  
then the next release can be produced by cherry picking innovations  
that are actually complete, and bug fixes that are complete and tested.

So here is where "bob" could conceptually comes in...

With bob you can load your version of package A (e.g. Rio), as you  
maintain it in your local distribution, in your fork, and  
automatically test it. You make your "rio testing bob" open, so that  
anyone can add their distribution to the list. Bob downloads their  
image from their ftp site when it changes, and adds it to the test  
schedule. So, you can develop package A, seeing the impact you are  
making on every derived distribution in bobs list. When you see that  
package A's new feature is going to work for everyone, you can  
announce that feature and those who are interested can pull it over.  
At the same time, each user of package A, is also running the tests,  
so they get to see if they accidentally undermine package A, breaking  
by doing something silly.

5.

Currently, in its technically limited way, using Bob, and Sake/Tasks,  
you can write a script made of a series of tasks that you think would  
pull 200 fixes and update to the latest packages to make 3.10 into 3.11.

Then you can run that script against 3.9, and low and behold, 95% of  
that script will execute. Any parts that need a tweak, can be tweeked  
by subclassing or overriding the task that failed. In this manner some  
fixes can be omitted, or extra ones loaded if needed.

Then you can run that same script against your production image based  
upon 3.9, and it might well pass too. If it does, and you fix your  
production image to work, then this means, that all the code in your  
production image, can migrate to 3.11 seamlessly.

The net result will be, that there will be a new monticello,  
squeakmap, sunit, in squeak 3.11, but also, there will potentially be  
a 3.9.2 with that same new monticello, squeakmap and sunit, and also a  
3.8.4 with that same monticello, squeakmap and sunit. All generated  
and tested simultaneously.

If the pharo guys want to pull your 3.10-3.11 innovations, they simply  
add a subclass for pharo, let bob build Pharo1.0+(3.10 to 3.11 delta  
script) and see what works and what doesn't. Or they can see exactly  
what steps you went through to make 3.11, and they can cherry pick the  
ones they like. If the pharo guys made Pharo 1, from squeak 3.9 in the  
same manner then you could pull their innovations too. (this is the  
principle that the mercurial guys are aiming to support)

The more different forks, that load common fixes, (and I know not  
everything will work) the more compatability we will have, even though  
the kernels of the forks may be different.

Before you tell me that this wouldn't work, may I point out that LPF  
already did this for 8(?) different squeak forks, you can download 3.7- 
lpf, 3.8-lpf, cobalt-lpf etc etc.

In addition, Sake/Packages knows the package dependencies for all the  
packages that are loadable in 3.10, and 3.9, so bob can produce. 3.7- 
lpf + sake/packages = 3.7-build, 3.8-build, 3.9-build, cobalt2.0-build  
etc.

So, we can update and maintain 8 different forks to have the same scm  
tools, the same package management tools, and the same testing tools.

So... if we can achieve this by pushing out fixes and packages to  
different forks, then applying the same principles, of publishing the  
list of changes we make to move from, 3.10 to 3.11, as code. Other  
forks based on 3.10 can pull what they want of the changes, but they  
are not forced to accept everything we do. For example, I want a fork  
of 3.10 which uses Rio, so I wouldn't pull any of the fixes to  
FileDirectory.

The current situation is that "trunk" is the only head, and all  
contributors are working on it, because they are following their  
esteemed leader. The chances of removing FileDirectory from trunk is  
0, because of the legacy, it will never happen.

However if I choose to fork 3.10 and make an image which doesn't have  
FileDirectory, (YAY!), then I am on my own, because "trunk" is no use  
to me. However if "trunk" innovations were of use to me, then I  
wouldn't be on my own.

3.11 with FileDirectory can be tracked to produce a parallel 3.11 with  
Rio full integrated and FileDirectory removed..
Seaside with FileDirectory can be tracked to produce a parallel  
Seaside with Rio.

eventually FileDirectory can die a graceful death.

its just an idea

Keith







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