From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 10 Apr 2018 03:10:54 GMT
Subject: Re: [PATCH 03/16] replace-object: move replace_map to object store
Message-ID: <xmqq4lkj4uyp.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20180409224533.17764-4-sbeller@google.com>

Stefan Beller <sbeller@google.com> writes:

> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
>  object-store.h   |  8 ++++++++
>  replace-object.c | 17 +++++++----------
>  replace-object.h |  9 +++++++++
>  3 files changed, 24 insertions(+), 10 deletions(-)
>  create mode 100644 replace-object.h

With this, the relationship between an object X and another object Y
that replaces the object X is defined only within the scope of a
single repository.

The exception in reachability rule around these replacement objects
is also local to a repository (i.e. if traversal from refs reaches
X, then both X and Y are reachable and need to be kept from gc), so
I think this is a reasonable way to arrange things.