library: keep artist art maintenance self-healing and cheap

Move change detection into a desired CTE with UPDATE ... FROM so mass updates do not turn the trailing WHERE into a quadratic correlated scan, and so no-op passes write zero rows. Fold the trigger optimization into the 35->36 migration and re-check/rewrite it from onOpen, so a future migration cannot silently restore the full UPDATE triggers. Re-resolve artist detail art when the active source becomes ready, and cover artist search renames in a Room-level test.

app/src/test/kotlin/com/subtracks/data/db/LibraryDaoTest.kt

@@ -682,6 +682,24 @@ class LibraryDaoTest {
             assertEquals(listOf("art-2", "art-1"), dao.artistOnce(sourceId, "ar-1")!!.downloadedCoverArts)
         }
 
+    @Test
+    fun artistNameUpdatesKeepTheSearchIndexValid() =
+        runTest {
+            val sourceId = source()
+            val dao = db.libraryDao()
+            dao.upsertArtists(listOf(artist(sourceId, "ar-1", "Artist", albumCount = 0)))
+            dao.upsertArtists(listOf(artist(sourceId, "ar-1", "Renamed", albumCount = 0)))
+
+            val hits =
+                db.useReaderConnection { connection ->
+                    connection.usePrepared("SELECT COUNT(*) FROM artist_search WHERE artist_search MATCH 'Renamed'") {
+                        it.step()
+                        it.getLong(0)
+                    }
+                }
+            assertEquals(1L, hits)
+        }
+
     @Test
     fun artistArtDeduplicatesCoversBeforeApplyingTheFourCoverBudget() =
         runTest {

app/src/test/kotlin/com/subtracks/data/db/MigrationsTest.kt

@@ -222,9 +222,10 @@ class MigrationsTest {
     fun theArtistSearchTriggersIgnoreArtOnlyUpdates() =
         runTest {
             driver.open(":memory:").use { migrated ->
-                applySchema(migrated, 36)
-                MIGRATION_36_37.migrate(migrated)
+                applySchema(migrated, 35)
+                MIGRATION_35_36.migrate(migrated)
 
+                assertTrue(artistSearchTriggersOptimized(migrated))
                 assertTrue(
                     triggerSql(migrated, "room_fts_content_sync_artist_search_BEFORE_UPDATE")
                         .contains("UPDATE OF `name`, `sortName`"),
@@ -240,7 +241,7 @@ class MigrationsTest {
     fun theFreshDatabaseCallbackOptimizesTheArtistSearchTriggers() =
         runTest {
             driver.open(":memory:").use { connection ->
-                applySchema(connection, 37)
+                applySchema(connection, 36)
                 connection.execSQL(
                     "INSERT INTO sources (id, name, address, isActive, createdAt) VALUES (1, 's', 'http://x', 1, 0)",
                 )
@@ -249,15 +250,12 @@ class MigrationsTest {
                         "VALUES (1, 'ar1', 'Artist', 0, NULL)",
                 )
 
-                ArtistSearchTriggerOptimization.onCreate(connection)
+                ArtistSearchTriggerOptimization.onOpen(connection)
+                assertTrue(artistSearchTriggersOptimized(connection))
                 val before = long(connection, "SELECT total_changes()")
                 connection.execSQL("UPDATE artists SET coverArts = 'a' WHERE id = 'ar1'")
 
                 assertEquals(before + 1, long(connection, "SELECT total_changes()"))
-                assertTrue(
-                    triggerSql(connection, "room_fts_content_sync_artist_search_AFTER_UPDATE")
-                        .contains("UPDATE OF `name`, `sortName`"),
-                )
             }
         }
 
@@ -546,6 +544,10 @@ class MigrationsTest {
             for (i in 0 until indices.length()) {
                 connection.execSQL(indices.getJSONObject(i).getString("createSql").replace("\${TABLE_NAME}", name))
             }
+            val triggers = entity.optJSONArray("contentSyncTriggers") ?: continue
+            for (i in 0 until triggers.length()) {
+                connection.execSQL(triggers.getString(i))
+            }
         }
     }
 

app/src/test/kotlin/com/subtracks/data/db/QueryTimingMeasurementTest.kt

@@ -39,7 +39,12 @@ class QueryTimingMeasurementTest {
     fun setUp() {
         val context = ApplicationProvider.getApplicationContext<Context>()
         val driver = LoggingSQLiteDriver(BundledSQLiteDriver()) { executions += it }
-        db = Room.inMemoryDatabaseBuilder(context, SubtracksDatabase::class.java).setDriver(driver).build()
+        db =
+            Room
+                .inMemoryDatabaseBuilder(context, SubtracksDatabase::class.java)
+                .setDriver(driver)
+                .addCallback(ArtistSearchTriggerOptimization)
+                .build()
     }
 
     @After

app/src/test/kotlin/com/subtracks/data/repo/SourceRepositoryTest.kt

@@ -285,6 +285,15 @@ class SourceRepositoryTest {
             assertTrue("expected the stored file, was ${ref.url}", ref.url.startsWith("file:"))
         }
 
+    @Test
+    fun activeSourceBecomesReadyAfterThePreferencesLoad() =
+        runBlocking {
+            repository.addSource("nav", "http://a.example/", "u", "p", false)
+
+            val active = withTimeout(TEST_TIMEOUT_MS) { repository.activeSource.first { it != null } }
+            assertEquals(repository.activeSourceId().first(), active)
+        }
+
     @Test
     fun artistImageUsesTheNetworkOnlineAndOnlyCachedFilesOffline() =
         runBlocking {