From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jon Seymour <jon.seymour@gmail.com>
Subject: Re: [RFC 0/9] bisect: allow git bisect to be used with repos
 containing damaged trees.
Date: Tue, 26 Jul 2011 23:28:15 +1000
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Cc: Johannes Sixt <j6t@kdbg.org>, Junio C Hamano <gitster@pobox.com>,
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> Which means that it works in this case:
>
>
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=
 =C2=A0 =C2=A0bad bad bad
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 BAD
> =C2=A0 good good good
>
>
> but won't work in this case:
>
>
>
> =C2=A0 good good good =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0=
 good good good
> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 bad ba=
d bad
>

Of course, this doesn't mean that bisection is useless, only that you
have to choose the right kind of test!

So, while it is true that a commit local test such as those I was
proposing (e.g. git ls-tree or even my suggested tweak git rev-list
--objects --max-count=3D1) will be useless unless you happen to start
with the tip at the bad commit, it is not true that bisection in
general is useless.

=46or example, Junio's unconstrained git rev-list --objects | git
pack-objects test will be sufficient because a history that is

    good good good bad bad bad good good good

according to a commit local test, will be:

     bad bad bad bad bad bad bad good good good

from the point of view of a test that reaches the entire graph
reachable from a commit.

It will still be beneficial to do log(N) executions of git rev-list
--objects instead of  N executions of the same.

jon.