Re: Switching heads and head vs branch after CVS import

From: Linus Torvalds <torvalds@osdl.org>
Date: Aug 15, 2005, 02:49 UTC
Message-ID: <Pine.LNX.4.58.0508141937251.3553@g5.osdl.org>
In-Reply-To: <46a038f905081419057cc6b5cd@mail.gmail.com>

On Mon, 15 Aug 2005, Martin Langhoff wrote:

Show 7 quoted lines

> 
> > So in a cvsimport, you'll never see a merge back to the head, even if one
> > technically took place.
> 
> There may be some surprises in here! gitk --all shows at least one
> branch opening and merging back into origin, and it has figured it out
> correctly

Oh, wow. The new cvsimport is obviously being a hell of a lot smarter than my original one was. Goodie.

> Except for the keyword expansion. surely there's a way to tell cvsps
> to not do it. Why would we ever want it?

Ahh. I don't think we should blame cvsps, I think cvsimport should use the "-ko" flag to disable keyword expansion or whatever the magic flag is.

Sven, Matthias, opinions? I've never used CVS keyword expansion, and always felt it was pointless, but hey..

Show 5 quoted lines

> > branches and heads are the same thing in git. 
> 
> right. There are two separate directories in .git for them, so I was
> misled by that. Should I assume git is safe from name clashes or is it
> up to porcelain to deal with such minutiae?

Well, you actually are _expected_ to get clashes.

What happens normally (at least for core git) is that the ".git/branches" directory contains external sources for the branches (for example, a "git clone" will fill in the "origin" source, while I often have a ".git/branches/parent" in my tree because). That is just a pointer to where the external branch exists.

Then, when you do something like

	git fetch parent

it will look up the source of "parent" by looking in the ".git/branches/parent" file, and update the ".git/refs/heads/parent" branch appropriately from that external branch.

So in this example the parent "head" ("local branch") points to the actual _commit_ we have, while the ".git/branches/parent thing points to what _external_ branch it came from.

But yes, you _can_ mess this up if you want to. If you have the same "external branch" name that you use for an "internal branch", you deserve all the confusion you get ;)

		Linus