git/cogito workshop/bof at linuxconf au?

Anyone coming to Linuxconf.au 2006? It'll will be in Dunedin NZ and I'd be really keen on joining a git/cogito workshop or bof.

I would gladly try and organize a workshop, but I am far from fluent with git, so I won't go at it alone. Any takers? Call for papers ends 5th September, not too far ahead. We have to register our interest _now_.

cheers,

martin

On Sat, 13 Aug 2005, Martin Langhoff wrote:

I was planning to be there. I like lca, but passed it over this year because of it being in Canberra (I'm sure it's a nice city to live in, but it's not a very exciting one, and I've been there several times before ;)

I'm no good with papers, though. One of the reasons I decided to leave the university lifestyle was that I hate writing papers. That's anti-conductive to being at a uni ;)

		Linus

On 8/14/05, Linus Torvalds <torvalds@osdl.org> wrote:

And how are things lining up for the upcoming one (January 2006, Dunedin, NZ)?  

Workshops and BOFs don't need to be paper-backed at all. Though it's not unlikely that someone with an interest in SCM theory would write a paper covering git. I think the main interest would be to bring git practical usage to the masses.

There's a lot of interest, but the barriers of entry are somewhat high, with the codebase moving fast, and some of the concepts requiring re-learning of what to expect from an SCM. Perhaps no so much among kernel hackers, but the general populace is largely still laden with cvs/svn and their mindset.

cheers,

martin

On Sun, 14 Aug 2005, Martin Langhoff wrote:

Dunno yet. I have a policy of trying to travel with the whole family, which means I'll have to decide whether I'm willing to put that much money into it, or whether some poor unsuspecting company can help sponsor me ;) We'll see.

Yeah. We do not have a nice paper explaining the concepts and usage. The tutorial isn't really in-depth enough (it doesn't even mention a lot of the helper scripts or even some of the core stuff). The old README started out explaining some of the concepts, but it's _way_ of out date in all usage respects.

Pasky has the Overview thing, which gets pointed to by kernel.org, and which could be expanded upon a lot.

I'll happily help anybody who wants to try to write some nice documentation (answer questions etc), but I'm just not very good at doing it myself.

		Linus

Dear diary, on Sun, Aug 14, 2005 at 01:33:53AM CEST, I got a letter where Linus Torvalds <torvalds@osdl.org> told me that...

BTW, I've asked my unsuspecting company. I'll see too. ;-)

I wanted to offer a Git/Cogito tutorial session (Is that what is meant by "workshop"? I'm no skilled conference traveller and the website mentions no workshops.), but on a second thought paper might be better - Cogito is supposed to be so simple to use that a tutorial wouldn't give you much (except tutorial.txt since I would have a strong incentive to write it), and Git concepts aren't tutorial material. So I might try to apply with a paper giving some overview of the new wave of "modern" version control systems, with a special focus on GIT design and core interface. (I will probably skip the core GIT plumbing since I'm naturally a bit sceptical about it. ;-)

I also imagined a BOF session for more interested people (if there would be any), for discussing advanced topics, possible further development directions (see also the Cogito TODO for also some Git-related stuff I have on my mind but is not yet ready for mailing list bashing) etc.

Linus Torvalds wrote:

Here's something that I've been putting together on how I'm using GIT as a Linux subsystem maintainer.

I suspect that I'm a bit slap-happy with the "git checkout" commands in the examples below, and perhaps missing some of the _true-git_ ways of doing things.

-Tony

Linux subsystem maintenance using GIT -------------------------------------

My requirements here are to be able to create two public trees:

1) A "test" tree into which patches are initially placed so that they
can get some exposure when integrated with other ongoing development.
This tree is available to Andrew for pulling into -mm whenever he wants.

2) A "release" tree into which tested patches are moved for final
sanity checking, and as a vehicle to send them upstream to Linus
(by sending him a "please pull" request.)

Note that the period of time that each patch spends in the "test" tree is dependent on the complexity of the change. Since GIT does not support cherry picking, it is not practical to simply apply all patches to the test tree and then pull to the release tree as that would leave trivial patches blocked in the test tree waiting for complex changes to accumulate enough test time to graduate.

Back in the BitKeeper days I achieved this my creating small forests of temporary trees, one tree for each logical grouping of patches, and then pulling changes from these trees first to the test tree, and then to the release tree. At first I replicated this in GIT, but then I realised that I could so this far more efficiently using branches inside a single GIT repository.

So here is the step-by-step guide how this all works for me.

First create your work tree by cloning Linus's public tree:

 $ git clone rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git work

Change directory into the cloned tree you just created

 $ cd work

Make a GIT branch named "linus", and rename the "origin" branch as linus too:

 $ git checkout -b linus
 $ mv .git/branches/origin .git/branches/linus

The "linus" branch will be used to track the upstream kernel. To update it, you simply run:

 $ git checkout linus && git pull linus

you can do this frequently (as long as you don't have any uncommited work in your tree).

If you need to keep track of other public trees, you can add branches for them too:

 $ git checkout -b another linus
 $ echo URL-for-another-public-tree > .git/branches/another

Now create the branches in which you are going to work, these start out at the current tip of the linus branch.

 $ git checkout -b test linus
 $ git checkout -b release linus

These can be easily kept up to date by merging from the "linus" branch:

 $ git checkout test && git resolve test linus "Auto-update from upstream"
 $ git checkout release && git resolve release linus "Auto-update from upstream"

Set up so that you can push upstream to your public tree:

 $ echo master.kernel.org:/ftp/pub/scm/linux/kernel/git/aegl/linux-2.6.git > .git/branches/origin

and then push each of the test and release branches using:

 $ git push origin test
and
 $ git push origin release

Now to apply some patches from the community. Think of a short snappy name for a branch to hold this patch (or related group of patches), and create a new branch from the current tip of the linus branch:

 $ git checkout -b speed-up-spinlocks linus

Now you apply the patch(es), run some tests, and commit the change(s). If the patch is a multi-part series, then you should apply each as a separate commit to this branch.

 $ ... patch ... test  ... commit [ ... patch ... test ... commit ]*

When you are happy with the state of this change, you can pull it into the "test" branch in preparation to make it public:

 $ git checkout test && git resolve test speed-up-spinlocks "Pull speed-up-spinlock changes"

It is unlikely that you would have any conflicts here ... but you might if you spent a while on this step and had also pulled new versions from upstream.

Some time later when enough time has passed and testing done, you can pull the same branch into the "release" tree ready to go upstream. This is where you see the value of keeping each patch (or patch series) in its own branch. It means that the patches can be moved into the "release" tree in any order.

 $ git checkout release && git resolve release speed-up-spinlocks "Pull speed-up-spinlock changes"

After a while, you will have a number of branches, and despite the well chosen names you picked for each of them, you may forget what they are for, or what status they are in. To get a reminder of what changes are in a specific branch, use:

 $ git-whatchanged branchname ^linus | git-shortlog

To see whether it has already been merged into the test or release branches use:

 $ git-rev-list branchname ^test
or
 $ git-rev-list branchname ^release

[If this branch has not yet been merged you will see a set of SHA1 values for the commits, if it has been merged, then there will be no output]

Once a patch completes the great cycle (moving from test to release, then pulled by Linus, and finally coming back into your local "linus" branch) the branch for this change is no longer needed. You detect this when the output from:

 $ git-rev-list branchname ^linus

is empty.  At this point the branch can be deleted:

 $ rm .git/refs/heads/branchname

To create diffstat and shortlog summaries of changes to include in a "please pull" request to Linus you can use:

 $ git-whatchanged -p release ^linus | diffstat -p1
and
 $ git-whatchanged release ^linus | git-shortlog

Hi,

On Mon, 15 Aug 2005, tony.luck@intel.com wrote:

This is perfect material for the newly introduced howto/ directory! How about Documentation/howto/how-tony-luck-does-it.txt :-)

Ciao, Dscho

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

I already have done that pushed it out. Tony is clearly a winner with this one.