SetLinkDomains() tracks whether the configured search domain list changed
so it can skip redundant persistence. The route_only flag is part of the
D-Bus API and is persisted as a ~ prefix, but flipping an existing domain
between search and route-only only updated in-memory state and left
changed false. The method then skipped link_save_user() and
manager_write_resolv_conf(), leaving stale state until restart.
Reproduced on Ubuntu with systemd 259:
sudo resolvectl domain enp1s0 route-only-repro.test
sudo resolvectl domain enp1s0 '~route-only-repro.test'
resolvectl domain enp1s0
grep '^DOMAINS=' /run/systemd/resolve/netif/$(cat /sys/class/net/enp1s0/ifindex)
grep -H route-only-repro.test /run/systemd/resolve/*.conf
Before, resolvectl showed ~route-only-repro.test, but the persisted state
file still showed DOMAINS=route-only-repro.test, and the generated
resolv.conf files still contained search route-only-repro.test.
After this change, the state file is updated to
DOMAINS=~route-only-repro.test and the generated resolv.conf files are
refreshed so the route-only domain is not emitted as a search domain.
Follow-up for: cbf23f3853
dongshengyuan
628e8304cc