The two Recommended-Artist rails showed artists the user already follows
or blacklisted, and the same artist could appear in both rails at once.
Builders now retain the full validated pool (rotated, not truncated at
DISPLAY_CAP); the pools ride the results blob as before, so old blobs
simply have no overflow until they expire. A new pure compose step in
qbz-external-reco (unit-tested: exclusion, within/cross-rail dedup with
common-wins ordering, visible/overflow split order) runs at the single
paint choke point in external_reco.rs — covering BOTH the fresh build
and the cached-blob paint. Exclusions fold followed (fav_cache) +
blacklisted + reco-dismissed ids, each source independently fail-open.
The past-cap survivors are retained as overflow for the Not-interested
live backfill (no extra network).
km
vicrodh
465f8627eb