Re: Please undo "Use git-merge instead of git-resolve in

From: Linus Torvalds <torvalds@osdl.org>
Date: Sep 22, 2005, 21:12 UTC
Message-ID: <Pine.LNX.4.58.0509221355330.2553@g5.osdl.org>
In-Reply-To: <E1EIVsD-0001Hu-9m@jdl.com>

On Thu, 22 Sep 2005, Jon Loeliger wrote:

Show 11 quoted lines

> 
> For me, this paragraph suddenly turned on one missing light:
> The default construction of repository branches/heads _mismatches_
> names on local and remote ends: "origin" local came from "master"
> remote.  Did I miss reading that somewhere else? (Likely.)
> 
> And I sat through the Great Remote Name Discussion of '05
> ("How is working on arbitrary remote heads supposed to work in Cogito")
> but I just didn't get it back then.
> 
> (This is an intentional asymmetry, right?  Distributed systems, right?)

Right. It's intentional. The "master" branch tends to be the main one for everybody, but _my_ "master" branch is clearly _your_ "linus" branch, and _your_ "master" branch would be the "jon" branch for me.

So it's not "asymmetric". It _is_ symmetric, but it's symmetric the same way "left" and "right" are symmetric when facing each other - my left is your right, your left is my right. It's a symmetry, but it's not an _identity_.

And obviously, nobody is going to have every possible branch anyway. You just name the ones you care about (and that, in turn, _will_ break the symmetry ;)

Show 10 quoted lines

> In any case, I just tried this:
> 
>     git fetch rsync://www.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git master:origin
> 
> And got this mess:
> 
>     sent 18136 bytes  received 2731519 bytes  60431.98 bytes/sec
>     total size is 97584183  speedup is 35.49
>     rsync: link_stat "/scm/linux/kernel/git/torvalds/linux-2.6.git/objects/info/alternates" (in pub) failed: No such file or directory (2)
>     rsync error: some files could not be transferred (code 23) at main.c(1173)

Ok, ignore that error.

>     * non-commit: 3fd07d3bf0077dcc0f5a33d2eb1938ea050da8da
>       branch 'master' of rsync://www.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

Ok, 3fd07d3bf0077dcc0f5a33d2eb1938ea050da8da is my current head, so that part looks good. However, the "non-commit" part doesn't look good. It _should_ say "committish".

What does

	git-cat-file -t 3fd07d3bf0077dcc0f5a33d2eb1938ea050da8da

say in your tree? I suspect you don't have that object at all, and that the mirrors are still not in sync (ie I suspect you get a "error: unable to find 3fd..")

This, btw, is why I hate the rsync protocol. Quite frankly, it sucks. It was wonderful for bootstrapping git when we didn't have anything else, but dammit, it's horrid. It has no git knowledge at all, does _zero_ sanity checking, and leaves the user going "huh" when it fails.

>     * refs/heads/origin: does not fast forward to branch 'master' of rsync://www.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6;
>       leaving it in 'refs/heads/origin.remote'
> 
> And this is due to kernel.org being Not Quite Right, right?

Yes. It tries to verify that the new commit it stuffs into "origin" is a proper superset of the old one (so that you're not losing any data), and it fails, since the new commit doesn't even exist in your object list yet.

> Which points out one of the other points of frustration
> that I feel should be addressed eventually:  A whole section
> about "What To Do When It Goes Wonky" needs to be written.

Hey, you seem to have a good example of Wonky, maybe you want to write it?

> OK, so it didn't merge?  Now what?  What got left where?
> How do I recover?  What bits are in my tree, and what bits
> are in the Index, and what bits are in the Object store now?

The good news is, I don't think there's anything to recover. It refused to write the new head, because it wasn't valid yet.

Actually, the fact that it even left it as a head might cause problems (because now you have a reference to something that doesn't exist), so you are probably best off just removing the .git/refs/heads/origin.remote file entirely.

You just need to try again when the mirroring is doing better.

Oh. And I think you might want to change that "rsync:" to "http:" instead. It's going to be slower, but at least git-http-fetch should be more careful, since it's fetching one object at a time, and validating what it fetches that way. The rsync: protocol just does everything totally blidly (which makes it fairly efficient, but also means that when things go wrong, they are _really_ confusing).

		Linus