Re: How to Import a bitkeeper repo into git

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Oct 16, 2007, 00:45 UTC
Message-ID: <alpine.LFD.0.999.0710151711280.6887@woody.linux-foundation.org>
In-Reply-To: <4713FA4A.5090501@bluelane.com>

On Mon, 15 Oct 2007, Pete/Piet Delaney wrote:

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> 
> I imported the CVS repository to git and it worked great. Since all
> of our other repository are in bitkeeper the management would like to
> stick with CVS. With git apparently still being weak in the area of
> supporting difftool on different version that seems somewhat reasonable
> for the time being.

I can't see how bk's difftool could possibly have any relevance to the "reasonable to stick with CVS" decision, but hey, I'm always surprised by peoples inventiveness in rationalizing their decisions ;)

I don't know what difftool does that a simple

	git diff -U99 | viewdiff -

wouldn't do, but in all honesty, I don't think I ever used difftool (I found the other tools in bk much more useful - eg mergetool, renametool)

I don't actually know of any sane programs to view unified diffs, but you can script one with little trouble. Here's a really hacky one I just came up with:

	#!/bin/sh
	cat "$@" > /tmp/diff
	grep '^[ -]' /tmp/diff > /tmp/orig
	grep '^[ +]' /tmp/diff > /tmp/result
	meld /tmp/orig /tmp/result

which fools 'meld' into showing a unified diff in a nice graphical manner.

[ Quite frankly, I don't understand why tools like meld and kdiff3 can't 
  just take the unified diff directly - they have *all* the logic, it 
  should be trivial to do, and very useful to view diffs for those people 
  who like that graphical bling. ]

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> The folks at bitmover are converting you kernels to bk and it's
> maintaining the branch history and I'd like to do the same. So far
> they haven't help us convert the git repository to bk. Do you happen
> to know of someone else that might now how to do this in case the
> folks at bitmover can't provide the scripts to convert this git
> repository to bk?

Hmm. Converting from git to bk should not be that hard at least conceptually, but no, I have no idea how to script it sanely and efficiently. The obvious solutions all would want to have multiple active heads of development open at the same time (Larry calls them "LOD's" not branches), and would also require some way to set the result of a merge. Neither of which I would know how to do in BK (I created a lot of merges in BK, but I always let BK do the merging - I wouldn't know how to specify the merge result by hand).

		Linus