Re: git-bisect not working correctly in the kvm.git repository?

From: Johannes Sixt <j.sixt@viscovery.net>
Date: Nov 18, 2008, 07:13 UTC
Message-ID: <49226B26.4000807@viscovery.net>
In-Reply-To: <gfsjjp$o42$1@ger.gmane.org>

walt schrieb:

Show 19 quoted lines

> Linus Torvalds wrote:
>>
>> On Mon, 17 Nov 2008, walt wrote:
>>> I'm trying to find a bug introduced somewhere between kvm-69
>>> and kvm-70, so of course I want to git-bisect down to it.
>>>
>>> The weirdness is that when I give git-bisect the good and
>>> bad tags, almost everything in my working directory just
>>> disappears, leaving only the qemu subdirectory behind.
> 
>> ...
>> If you merge stuff from another project that isn't a full repository,
>> then
>> you are merging commits that simply don't _have_ the full tree of your
>> repo...
> 
> Okay, that's clearly what's happening to me.  The kvm.git repo
> contains hundred of commits just like that.  How would you deal
> with the same situation?  Is git-bisect skip the easiest way?

If you are pretty sure that the bug you are looking for was *not* introduced in the branch that was subtree-merged, you can mark it as "good" like so:

  $ git bisect start kvm-69 kvm-70 $BRANCH

where $BRANCH is the most recent commit on the subtree-merged branch. Watch out that you do *not* accidentally pick the *merge* commit that merged the branch in, but the (second) parent[*], the one that was merged in. Then your bisect sequence won't ever end up in that branch.

[*] If you happen to have the branch lying around as a remote ref, you can use that instead, even if it is ahead of what was merged in.

-- Hannes