3 Commits

Include renames

Author	SHA1	Message	Date
bvandeusenandClaude Opus 5	eff3d88931	fix(recommendation): make the candidate draw reproducible, not accidentally so ... Four arms of the candidate query ended in a bare `ORDER BY random()` with no seed: similar_artists, likes_overlap, coplay_artists and random_fill. Such an arm returns a STABLE set only while its LIMIT exceeds the rows eligible for it — at that point it returns all of them and the order stops mattering, because scoreAndSortCandidates sorts by track id before drawing jitter. Below that threshold it returns a random SUBSET, and two builds on the same day draw different ones. So daily determinism held BY ACCIDENT, and only for libraries smaller than the limits. Any real library is larger, which means same-day rebuilds have been producing different mixes since those arms were written — invisible, because a mix that changes after a refresh looks like a feature rather than a broken promise. Found by breaking it: cutting RandomFill to 10 while tuning Songs-like turned TestBuildSystemPlaylists_DailyNonceDeterminism red. That test seeds ~20 tracks against a default RandomFill of 30, so its determinism came from the limit exceeding the library, not from the code being right. It is now a real guard. The arms order by md5(id || $12) instead. The CALLER decides what that means, which is the point: system mixes pass a per-(user, day) seed and get the determinism they promise, radio passes a fresh value per request and keeps varying, which is what a radio should do. Same shape the browse queries in this file already use (`md5(id::text || current_date::text)`) — existing idiom, not a new one. This also unblocks the trim that #3881 wanted and could not have. Shrinking a randomly-ordered arm was what broke membership; a seeded one takes a smaller but REPRODUCIBLE slice. Songs-like's seed-independent share drops from 29% to 12%, which was the original intent before determinism forced it back to 20%. TestSongsLikeLimits_DoNotShrinkTheUnseededRandomArms is DELETED rather than kept passing. It existed to stop anyone trimming those arms while the ordering was broken; the ordering is fixed, so the constraint is gone and a guard enforcing it would now forbid correct code. Was filed as blocked on tooling. It was not: `make generate-go` runs sqlc as a pinned Go tool and is the same path CI takes. One thing worth knowing for next time: three files in internal/db/dbq are owned by root, left by `make generate` running sqlc in Docker. sqlc errored on the first it could not write. They are untouched by this change and the regeneration of recommendation.sql.go completed, but `make generate` will keep failing until they are chowned. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01SQ31KQpYbStyK5y58UmPLH	2026-09-11 08:44:33 -04:00
bvandeusenandClaude Opus 5	ecfa056d4d	fix(recommendation): don't shrink a candidate arm ordered by unseeded random() ... Fixes the integration failure from f367eeaa: "same-day rebuild produced different track lists". Cutting RandomFill 30→10 for Songs-like broke TestBuildSystemPlaylists_DailyNonceDeterminism, and the reason is worth stating because the number is not the bug. `likes_overlap` and `random_fill` end in a bare `ORDER BY random()` with no daily seed (recommendation.sql:118, :161). Such an arm returns a STABLE set only while its LIMIT exceeds the rows eligible for it — then it returns all of them, and the random order stops mattering because scoreAndSortCandidates sorts by track id before drawing jitter. Below that threshold the arm returns a random SUBSET, and two builds on the same day draw different ones. So the test was green by accident. It seeds ~20 tracks against a default RandomFill of 30; the limit exceeded the library, so the arm returned everything. Determinism held for a reason unrelated to the code being right. Which means it does NOT hold in production. Any real library is larger than 30, so same-day rebuilds have been drawing different mixes since that arm was written — invisible, because a mix changing after a refresh looks like a feature. Filed as #3889; the fix is a seeded ordering per (user, day), which needs a .sql change and sqlc regeneration and so cannot land from here. The correction: grow an arm freely, never shrink one whose ordering is unseeded random. LikesOverlap and RandomFill go back to the defaults; TasteOverlap stays halved because it sorts by `tpa.weight DESC, t.id` and is genuinely deterministic. Guarded by a test that names the reasoning, so the next person to trim these has to read why first — and it should be DELETED once #3889 lands rather than worked around. The cost is honest: the seed-independent share of the Songs-like pool falls from 29% to 20% instead of the intended cut. That matters less than it sounds. The pool only biases the draw; the songs_like WEIGHTS are what actually demote sim_score-0 candidates, and they are untouched here — a perfect match still scores 5.00 against an unrelated favourite's 2.00. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01SQ31KQpYbStyK5y58UmPLH	2026-09-10 20:59:39 -04:00
bvandeusenandClaude Opus 5	f367eeaa9d	fix(recommendation): Songs-like gets its own profile so it stops wandering ... Operator, 2026-09-10: "when I play it I'm expecting to get a consistent sound and style from the experience... I was getting a seeming wide variety of music from each one when I was hoping to stay in a certain neighborhood." Songs-like shared the `daily_mix` weight profile with For-You, and that sharing WAS the bug. The two surfaces want opposite things: For-You answers "what will they enjoy today" and is supposed to roam; Songs-like answers "what sounds like THIS". Under one profile the broad answer wins. The arithmetic, from the shared weights: unrelated track, liked, not played recently → 1.0 + 2.0 + 1.0 = 4.0 PERFECT similarity match, not liked → 1.0 + 1.5 = 2.5 Liking something outranked sounding like the seed, because LikeBoost (2.0) exceeded SimilarityWeight's whole range (1.5) and TasteWeight (1.5, and seed-INDEPENDENT) matched it outright. Under the new profile the same pair scores 5.00 vs 2.00. Two levers, because either alone leaves the other's failure intact: POOL. Songs-like now takes its own CandidateSourceLimits. The default gave ~29% of candidates a sim_score of literally zero — `taste_overlap` and `random_fill` are both `0.0::float8` in recommendation.sql, seed-independent by construction. Same total pool size; composition shifts to arms that measure distance from the seed, LBSimilar doubled. WEIGHTS. A third profile beside radio and daily_mix, DB-backed and live per rule 25, with the property that similarity's range exceeds the combined range of every seed-independent differentiator — so a closer match cannot be beaten on likes, freshness and taste alone, while tracks within ~0.39 similarity of each other still get ordered by what the user likes. Rule 131 changed the pool design mid-way and for the better. Zeroing the two seed-independent arms was the first instinct and is exactly the vanish-or-nothing shape that rule forbids: a seed with thin ListenBrainz coverage would yield a short mix or none. They are the tier-3 FLOOR — cut hard, never removed — and the weights keep them at the bottom of the ranking rather than out of the pool. "A few tracks further from the seed than we'd like" beats "no playlist". Caught while wiring it: switching only pickTopN's final Score would have been nearly INERT. scoreAndSortCandidates does the selection sort, and the caller caps and truncates in that order — so the playlist would still have been chosen by daily_mix and merely relabelled with songs_like numbers. It now takes the profile as a parameter, and each surface passes its own. Also corrects the daily_mix card's blurb, which claimed Songs-like as one of its surfaces and no longer is. Guards pin behaviour rather than the numbers, since numbers get retuned: that similarity beats an unrelated liked track, that daily_mix still DOESN'T (or the split buys nothing), that the tier-3 floor is non-zero, and that the UI card shows its own values rather than falling back. Each falsified against its named regression first. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01SQ31KQpYbStyK5y58UmPLH	2026-09-10 20:51:15 -04:00