Re: [RFC PATCH] index-pack: optionally allow duplicate objects

[friel@openai.com]

From: Friel <friel@openai.com>

On Wed, Jul 29, 2026 at 01:32:39PM -0700, Junio C Hamano wrote:

> I can live with such an extension as long as we teach the receiving
> end to deduplicate the extra copy.

That makes sense. We don't want packs containing duplicate objects to
become a persistent source of duplicate objects in other repositories.

For our server, duplicate objects would be an exceptional consequence of
an optimization, not normal operation. We have not seen duplicates in
practice yet. But preventing them imposes a cost on every upload-pack
request even when duplicates are rare.

I'll talk with Taylor about whether the client should repack when it
detects duplicates, or whether Git already has a way to mark such a pack
as dirty for reuse or retransmission until it has been cleaned up.
The intent would be to pay that cost only when duplicates actually
occur.

In all humility, thank you for reviewing and considering the RFC PATCH.
I'm still getting acquainted with mailing list and the history of Git,
and I'm happy to have Taylor & Ted's help.

Cheers,
Friel