Re: Please pull ACPI updates

From: Linus Torvalds
Date: Thu Jul 17 2008 - 16:01:42 EST



On Thu, 17 Jul 2008, Andi Kleen wrote:
>
> The whole point of the exercise of cleaning up/rewriting the history is to make
> the tree as bisectable as possible.

No.

"git bisect" is perfetly able to handle merges. They are _fine_.

The problem with rebasing is that it *changes* something that was already
tested (and possibly merged into somebody elses tree) into SOMETHING ELSE.

And that means that a large portion of the previous testing is basically
thrown away.

In particular, if something worked for somebody before, it also removes
the "known good state" from a bisection standpoint, so rebasing actually
makes things _harder_ to bisect - because now you cannot sanely bisect
between two versions of the tree (when you mark the old tree "good", it
has no relevance to the new tree that had all the old history rewritten).

So no, rebasing does _not_ make bisection easier. It makes it easier to
understand, perhaps, but it actually makes many things much much harder,
and removes all trace of any testing coverage that the old commit had.

Linus
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