Track the catalog zone SOA serial per view instead of a single global value.
The new CatalogZone model has a 1:1 FK to netbox_dns.models.View and its own
soa_serial field; each view's catalog zone now increments independently. The
existing global serial is preserved during migration by copying it into every
view's new CatalogZone row.
Change CatalogZoneMemberIdentifier.name from globally unique to unique per
catalog zone (UniqueConstraint(name, catalog_zone)) and add a catalog_zone FK
to enforce it.
Remove the dns-settings management command, which was a generic interface over
the now-removed IntegerKeyValueSetting model.
Increment both catalog zone serials when a zone moves between views: the old
view's catalog zone loses a member and the new view's gains one, so both must
be bumped. Also refresh the member identifier's catalog_zone FK on a view move
so it does not go stale. The pre_save handler now captures _old_view_id and the
post_save handler detects view changes, increments the old view's serial inside
on_commit (before the new view's), and re-creates the identifier.
AI generated, code manually verified.
IntegerKeyValueSetting is used as a singleton-style key/value store:
callers do get(key=...) and get_or_create(key=..., ...) and assume at
most one row per key. The model, however, did not enforce uniqueness on
the key field, so nothing prevented duplicate rows at the database
level.
This was a real race for _create_soa_rdataset in catalog_zone_manager,
which calls get_or_create without select_for_update (unlike
increment_soa_serial, which does take a lock). Two concurrent AXFR
queries for a catalog zone could both pass the get_or_create existence
check and both insert a row for key='catalog-zone-soa-serial'. Every
subsequent IntegerKeyValueSetting.objects.get(key=...) call would then
raise MultipleObjectsReturned, breaking catalog-zone SOA rendering and
serial increments.
Add unique=True to the key CharField and ship migration 0003 to enforce
the invariant at the database level. Existing deployments are assumed to
have clean state (no duplicate keys); if duplicates exist, the migration
should be preceded by manual deduplication.