>
> Hello Git developers,
>
> A push can resend common history if its pre-push hook repacks the local
> object database and removes previously loose common objects. I reproduced
> this with Apple Git 2.54.0 (Apple Git-157) and an unmodified build of the
> current upstream Git 2.56.0 release on macOS 27.0 / arm64.
>
> The attached inline Python script creates fresh local repositories, seeds
> a bare receiver with a deterministic, incompressible 4-MiB historical blob,
> and pushes one tiny text-file commit. The common base is initially loose.
> The receiver uses receive.unpackLimit=1 so the added pack is measurable.
> Each case starts from a separate fresh repository pair. All pushes succeed
> and the receiver ends at the expected tip.
>
> Observed added receiver pack sizes, in bytes:
>
>                         Apple Git 2.54.0    upstream Git 2.56.0
>   no hook                      300                  300
>   repack in pre-push      4,196,026            4,196,026
>   repack + negotiate     4,196,026            4,196,026
>
> The repacking hook is simply:
>
>   #!/bin/sh
>   set -eu
>   cat >/dev/null
>   git repack -adq
>   git prune-packed
>
> Expected: the already-advertised common history should still be excluded
> when its storage moves from loose objects to a newly created pack.
> Actual: the historical blob is transmitted again. The receiver stores a
> new pack roughly the size of the historical blob. Enabling
> push.negotiate=true does not prevent the redundant transfer in this test.