Sequential dial of unresolved same-realm AoR hairpins INVITE to the PBX (instant failure)

[autopeasant]

Summary

When building dialplan targets for a same-realm callee, default_resolve seeds locs with Location { aor: callee_uri } even when locator lookup is empty. Sequential dial then INVITEs sip:user@pbx-bind-ip with no registered destination → request is effectively hairpinned to the PBX and fails immediately (No response from callee / 500), before any real fallback target runs.

Impact

• Offline extension + sequential fallback (e.g. mobile via sip.linphone.org): first target is a useless hairpin; adds delay/noise and confuses logging.
• Any “try local then external” plan that relies on empty locator meaning “skip local” does not work without custom inspectors.

Expected

If same-realm locator lookup is empty, do not enqueue a bare local AoR without destination. Either:

1. Leave targets empty (480 / offline marker), or
2. Only enqueue destinations that have a resolved contact / explicit external URI.

Suggested fix

When internal_lookup_empty, locs.clear() before appending fallback/forward targets (or never push the unresolved seed AoR when lookup returns empty).