Re: [PATCH] midx: traverse the local MIDX first

From: Derrick Stolee <stolee@gmail.com>
Date: Aug 28, 2020, 18:27 UTC
Message-ID: <9a599bb5-fb6f-1e35-6e02-d62703ebc420@gmail.com>
In-Reply-To: <20200828180621.GA9036@nand.nand.local>

On 8/28/2020 2:06 PM, Taylor Blau wrote:

Show 11 quoted lines

> This invariant is only preserved by the insertion order in
> 'prepare_packed_git()', which traverses through the ODB's '->next'
> pointer, meaning we visit the local object store first. This fragility
> makes this an undesirable long-term solution, but it is acceptable for
> now since this is the only caller.
> 
> Signed-off-by: Taylor Blau <me@ttaylorr.com>
> ---
> This is kind of a hack, but the order that we call
> 'prepare_multi_pack_index_one()' from 'prepare_packed_git()' makes it
> acceptable, at least in my own assessment.

The natural alternative would be to scan the list _after_ all are inserted and pull any MIDX marked "local" to the front of the list. Such a check would need to happen in the same method that iterates over all alternates, so that seems a bit redundant.

While perhaps a bit hack-ish, I think this is a sound approach. And, we have a test that will detect change in behavior here!

Thanks, -Stolee