Re: basics... when reading docs doesn't help

On Fri, 30 Mar 2007, Linus Torvalds wrote:

You need to mark "refs/heads/origin" as always following the remote 
"master", even if it gets re-based.  You do that by adding a "+" before 
the refspec that describes the remote.

These days, with git-1.5.x, "git clone" will do that for you (and make the 
remotes fall under "refs/remotes/origin/*" instead - they're considered 
separate branches from the local branches these days). However, since you 
created the repository with an older git version, it still uses the 
original format (and even though you upgraded your git binary, it will use 
the old-fashioned branch format for remote branches and for 
configuration).

So in your case, the remote is probably described by the 
.git/remotes/origin file, and it looks something like

	URL: git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
	Pull: master:origin

and you should just change that "Pull:" line to have a "+" in front of the 
refspec:

	URL: git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
	Pull: +master:origin

which tells git that the remote "master" branch should now 
*unconditionally* be followed into the local "origin" branch when you 
pull.

(In a more modern setup, you wouldn't have a .git/remotes/origin file at 
all, insead you would have something like this in the .git/config file:

	[remote "origin"]
		url = git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
		fetch = +refs/heads/*:refs/remotes/origin/*

	[branch "master"]
		remote = origin
		merge = refs/heads/master

which means that there is a remote called "origin", and all of the remote 
heads in that remote ("refs/heads/*") will be fetched into the local 
repository under "refs/remotes/origin/*". And the "+" again means that we 
do this even if it's not a fast-forward, ie we trust the remote 
explicitly.

So "git fetch origin" will fetch *all* branches from "origin" into your 
local repository, but to distinguish them from your *own* branches, they 
will be under .git/refs/remotes/ instead of your "real" local branches 
that are in ".git/refs/heads/. So you can now see the difference between 
your *local* version of a branch X and the remote version of that same 
branch by using "X" and "remotes/origin/X" respectively to describe that 
branch.

Then, the second part of the above config file means that when you're on 
the local "master" branch and do a "git pull", it will fetch it from the 
remote "origin", and merge the remote "refs/heads/master" branch from that 
remote (the same one that will be fetched into refs/remotes/origin/master 
by a "git fetch".

Yeah, this is all a bit complex, and it takes a while to wrap your head 
around it, but I have to say, once you do, the git-1.5.x layout really 
*is* very powerful, and it's actually very natural too (but the "very 
natural" part only comes after you have that "Aaahh!" moment!)

Aha, so, that's how it is then! Why hasn't anybody explained this to me 
strait away?!:-))))

Yeah, hopefully, I'll learn to at least use this thing efficiently enough. 
Someone has to write a book on it though...

And, so, it's a pity I cloned Paul's tree yesterday with the "old" git. 
And from your answer above it seems like some features of the "new" git 
will not be available with this tree, like equally named local and remote 
branches, etc. There isn't a way to convert such a "old style" tree to the 
"new style", is there? Not a big deal, will re-clone at some point, maybe 
when we get local git mirrors...

Many thanks for taking your time to answer, Linus!
Guennadi
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Guennadi Liakhovetski