search() collected ef candidates, then filtered out soft-deleted nodes, then
took k. When the records nearest a query had been deleted, every candidate was
a tombstone and the search returned fewer than k results — 39 of 40 queries in
the new test, which deletes each query's 40 nearest neighbours.
search_layer takes an optional skip mask: a skipped node is still pushed onto
the candidate queue (a tombstone is a valid waypoint) but never into the
result heap, so the ef result slots hold live nodes only. Build and insert
pass no mask. Recall and speed without deletions are unchanged.
Co-Authored-By: Claude Fable 5.1 <[email protected]>
