fix(api): read the live trending rows in Discover Weekly

api/v1_users_discover_weekly.go

@@ -238,13 +238,21 @@ func (app *ApiServer) getDiscoverWeeklyTrackIds(
  GROUP BY owner_id
 	),
 	-- Source 1: weekly trending tracks.
+	--
+	-- No genre predicate, deliberately. track_trending_scores holds two
+	-- populations: rows carrying a genre, which are the live list the trending
+	-- job refreshes (median track age ~4 days), and rows with a null/empty
+	-- genre, which are stale -- in production those resolve to tracks five to
+	-- six years old. GET /tracks/trending and /tracks/trending/underground read
+	-- the live rows by omitting the genre filter, so this does the same.
+	-- Matching on a null-or-empty genre instead reads the stale population and,
+	-- combined with the age cutoff below, returns nothing at all.
 	cand_trending AS (
  SELECT tts.track_id, 'trending'::text AS source
  FROM track_trending_scores tts
  WHERE tts.type = 'TRACKS'
  AND tts.version = 'pnagD'
  AND tts.time_range = 'week'
- AND (tts.genre IS NULL OR tts.genre = '')
  ORDER BY tts.score DESC, tts.track_id DESC
  LIMIT 400
 	),
@@ -258,7 +266,6 @@ func (app *ApiServer) getDiscoverWeeklyTrackIds(
  WHERE tts.type = 'TRACKS'
  AND tts.version = 'pnagD'
  AND tts.time_range = 'week'
- AND (tts.genre IS NULL OR tts.genre = '')
  AND au.follower_count < 1500
  AND au.following_count < 1500
  ORDER BY tts.score DESC, tts.track_id DESC

api/v1_users_discover_weekly_test.go

@@ -360,3 +360,44 @@ func TestV1UsersDiscoverWeeklyRequiresValidUserId(t *testing.T) {
 	status, _ := testGet(t, app, "/v1/users/not-a-real-id/discover-weekly", &resp)
 	assert.Equal(t, 400, status)
 }
+
+// Regression for the bug that shipped in #1025 and returned an empty mix for
+// every user in production.
+//
+// track_trending_scores holds two populations: rows carrying a genre, which
+// the trending job keeps current, and rows with a null/empty genre, which are
+// stale and resolve to tracks five to six years old. The original query
+// matched only the null-genre rows, so every candidate then failed the
+// 365-day age cutoff and the mix came back empty.
+//
+// Every other test here seeds score rows without a genre, so none of them
+// could catch it. This one seeds a genre-carrying row specifically -- the
+// shape that actually reaches the query in production.
+func TestV1UsersDiscoverWeeklyReadsGenreCarryingTrendingRows(t *testing.T) {
+	app := emptyTestApp(t)
+
+	fixtures := database.FixtureMap{
+ "users": []map[string]any{
+ {"user_id": 1, "handle": "me", "handle_lc": "me", "wallet": "0x0000000000000000000000000000000000000001"},
+ {"user_id": 2, "handle": "artist", "handle_lc": "artist", "wallet": "0x0000000000000000000000000000000000000002"},
+ },
+ "aggregate_user": []map[string]any{
+ {"user_id": 1, "follower_count": 0, "following_count": 0},
+ {"user_id": 2, "follower_count": 5000, "following_count": 10},
+ },
+ "tracks": []map[string]any{{"track_id": 200, "owner_id": 2, "title": "genred track", "genre": "Rock"}},
+ "aggregate_track": []map[string]any{{"track_id": 200, "save_count": 100, "repost_count": 50}},
+ "track_trending_scores": []map[string]any{
+ {"track_id": 200, "score": 1_000_000_000, "time_range": "week", "genre": "Rock"},
+ },
+	}
+	database.Seed(app.pool.Replicas[0], fixtures)
+
+	var resp struct {
+ Data []dbv1.Track
+	}
+	status, _ := testGet(t, app, "/v1/users/7eP5n/discover-weekly", &resp)
+	assert.Equal(t, 200, status)
+	assert.Len(t, resp.Data, 1,
+ "a score row carrying a genre must still be a candidate")
+}