Re: How to remove a commit object?

From: Michael J Gruber <git@drmicha.warpmail.net>
Date: Oct 2, 2008, 14:00 UTC
Message-ID: <48E4D3E9.8020906@drmicha.warpmail.net>
In-Reply-To: <33f4f4d70810020636g77f4180cm7aa6b7de07ae5beb@mail.gmail.com>

Klas Lindberg venit, vidit, dixit 02.10.2008 15:36:

Show 20 quoted lines

> This doesn't seem to work for me. I will soon be in a situation where
> I need to selectively delete commits in such a way that they become
> completely irrecoverable. I.e. it is not enough to revert a commit.
> The *original* commit must be removed. And of course, the repo history
> is too complex to allow for rebasing followed by garbage collection or
> something like that.
> 
> The reason is that we consider opening a repository to external
> participants, but some commits contain stuff that we'd really rather
> not show to anyone else. Making the repository public without loosing
> history would then force us to either
> 
>  1. Recreate every commit in a new repo, sans the offending commits.
> Seems like hard work.
>  2. ?
> 
> Would it be feasible to write a tool that can selectively replace a
> specific commit in the commit DAG, or would that automatically
> invalidate every SHA key for every commit that follows the replaced
> original?

Yes, on the or part: If you change a commit then all commits "after" that one (in terms of DAG connectedness) will need to be changed: each contains a "backpointer" (to the parent commit(s)) which is changed.

I'm a bit confused: You rule out rebasing but don't mind recreating a new repo. So repo size is not a problem, is it?

Michael