Re: How to use filter-branch with --state-branch?

From: Ian Campbell <ijc@hellion.org.uk>
Date: Mar 9, 2018, 13:23 UTC
Message-ID: <1520601834.2474.27.camel@hellion.org.uk>
In-Reply-To: <CAGen01hYG40jKQSu7ZJpb8TXROC74NfVXVT82wNjYqx1yKYD=w@mail.gmail.com>

On Fri, 2018-03-09 at 14:04 +0100, Michele Locati wrote:

> Just a couple of questions:
> 
> 1. it seems to me it's not possible to process all the branches in one
> go. Am I right?

I'm not sure, I've never done such a thing, in fact I didn't know you could.

Really all this feature does is record the `.git/rewrite-map` (or whatever the correct name is) at the end of the rewrite and reinstate it again the next time, so it shouldn't really interact with many of the other options.

My method for storeing "last version processed" in a branch does conflict I suppose (since that branch would be rewritten) but that's an artefact of the surrounding scaffolding -- you could equally well keep the record in some file on the local system or in a non-branch-ish ref (I guess).

> 2. Why do you have this line in filter.sh?
> `rm -f .git/refs/original/refs/heads/${UPSTREAM_REWRITTEN}`

TBH I'm not really sure. I originally wrote this patch many years ago, it's just recently that I got around to upstreaming, so my memory is more fuzzy than might be expected.

I think perhaps I was trying to avoid this error:

    A previous backup already exists in $orig_namespace
    Force overwriting the backup with -f"

which comes if there is an existing backup (a safety feature in the non-incremental case).

Note quite sure why I didn't use `-f` as the message says, but I guess because it forces other things too which I didn't want to do?

Perhaps what I should have done is make that check conditional on the use of --state-branch.

I wonder if you could use the `original/refs/...` as the "last version processed"? Would be a lot less manual messing around than what I do!

Ian.