Moodle in English

You need to distinguished the objects (the blobs contaning the files, directories, commits, and so on) and the references ("pointers" to some of those objects). This is a big difference from CVS and Subversion.

When you talk about MOODLE_19_STABLE, that's just a reference to a given object. Most of the time it'll be a commit object that records the state of a set of other objects (directories, files, etc.), a time, a committer and other metadata (like references to other parent commit objects).

When you clone a repository you clone the objects (i.e., you have all the content and the history of the repository) and most of the references. But those references a 'renamed' during the clone process. What was called 'MOODLE_19_STABLE' in the original repository is now called 'origin/MOODLE_19_STABLE' (by default, as you can name your remote repositories the way you want). And much the same for all the branch references for the original repository.

And by default you get a local 'master' branch reference that points to the same object that 'origin/master' (or in the case of Catalyst's Moodle repository 'origin/cvshead').

So if you wan to have a local MOODLE_19_STABLE branch to hack on, you just create a new local branch reference with:

git branch MOODLE_19_STABLE origin/MOODLE_19_STABLE

You haven't created any new object yet. Not until you commit something. You just have a new reference pointing to existing objects. By the way, the previous command creates a new branch (or branch reference, if you prefer), but doesn't check it out. You can do both things with:

git checkout -b MOODLE_19_STABLE origin/MOODLE_19_STABLE

By the way, if you want to show what branches a given remote repository has (you can clone from multiple repositories) and which ones you are tracking with local branches, you can use:

git remote show 'remote-repository-name-here'

(where 'remote-repository-name-here' will be 'origin' most of the time).

Saludos. Iñaki.

* The command git branch mymoodle origin/MOODLE_16_STABLE ... how do you know MOODLE_16_STABLE exists?

'git remote show origin' tells you that.

What does "origin" in that signify - why can't you just leave it out?

When you use 'git clone' to clone a repository, if you don't specify a name for that remote repository it gets called 'origin' automatically. You can't leave it out because you can clone/track several repositories at the same time, so you need to specify which one you want to work with.

* The bit entitled "To get updated from cvs/catalyst". Why is this so complicated (a fetch, a checkout and a merge)? My naive interpretation was that just fetch should get the changes but it seems more complicated. It's not clear in the docs.

Fetch only downloads the missing objects from the remote repository and updates the remote references (those 'origin/MOODLE_XX_STABLE names), but not your local objects or references (most people usually don't want that, so git doesn't do it).

So if you want to merge the remote changes in your local branches, you need to a) fetch the remote changes, b) checkout the local branch you want to modify based on those changes and c) merge those changes on your local branch.

If that's the only thing you want to do with that local branch, you can combine the fetch and merge step in just one operation with 'git pull'. You first check out the local branch you want to update and then execute:

git pull

and presto!

Remember this is distributed world. Your repository is just another copy of the remote repository. But it's a different repository so it can have a completely different history from the point you cloned onwards. That's why you manually have to fetch and merge things, so you can decide what you want to do with your repository.

Welcome to distributed world, where everything is a bit more flexible and complicated

Saludos. Iñaki.