> Hi,
>
> writing alternates into the object database currently happens via
> `odb_source_write_alternate()`. But while that creates the ability to
> create alternates at arbitrary points of a source's lifetime, we don't
> use that functionality in the first place. Instead, we only ever write
> alternates when creating a new repository.
>
> This design is suboptimal due to a couple of reasons:
>
>   - It requires us to have a `write_alternates()` callback, which is
>     overblown as we never even write alternates to an object database
>     after it has been created.
>
>   - We're about to make alternates an implementation detail of the
>     object database's backend in a future patch series, so alternate
>     implementations may not even support them.
>
>   - The backend has more flexibility with how exactly alternates are
>     configured when it itself is in full control over their setup at the
>     time where it creates the object database itself.
>
> This patch series thus refactors how we handle alternates so that we
> don't write them ad-hoc anymore. Instead, the series introduces a new
> option for `odb_source_create_on_disk()` that makes it handle those
> alternates at creation time.
>
> This is part of the bigger goal of moving handling of alternates into
> the "files" backend.
>
> This series is built on top of 2c3adbb2c4 (The 18th batch, 2026-08-24)
> with ps/odb-eagerly-load-alternates at 0076dc9f81 (odb: drop
> `alternates_db` field, 2026-08-17) merged into it.
>
> Changes in v2:
>   - Use a lockfile to write "info/alternates" during creation time.
>   - Remove useless "strvec.h" include by reordering declarations a bit.
>   - Link to v1: https://patch.msgid.link/20260825-pks-odb-write-alternates-at-creation-time-v1-0-911513ba95c3@pks.im