android/app/src/main/java/com/fabledsword/minstrel/api/AuthCookieInterceptor.kt

@@ -7,11 +7,23 @@ import javax.inject.Inject
 import javax.inject.Singleton
 
 /**
- * Attaches the session cookie from [AuthStore] to every request,
- * captures Set-Cookie from successful responses (login flow), and
- * clears the store on 401 so downstream code can react to logout.
+ * Attaches the session cookie from [AuthStore] to Minstrel-server
+ * requests, captures Set-Cookie from successful responses (login
+ * flow), and clears the store on 401 so downstream code can react
+ * to logout.
  *
  * Mirrors the Flutter Dio interceptor pattern.
+ *
+ * Scoped to the [BaseUrlInterceptor.PLACEHOLDER_HOST] sentinel host
+ * the same way BaseUrlInterceptor is. Drift #568 / #569 caught two
+ * leaks here: (1) the session cookie was being attached to every
+ * external request the shared OkHttpClient services — including
+ * Coil image fetches to artwork.musicbrainz.org / coverartarchive.org
+ * / Lidarr's /MediaCover endpoints — exposing the session
+ * identifier to third-party logging; (2) a 401 from any of those
+ * external hosts silently wiped the user's Minstrel session.
+ * Restricting both attach + clear to placeholder-host requests
+ * closes both gaps.
  */
 @Singleton
 class AuthCookieInterceptor @Inject constructor(
@@ -19,8 +31,15 @@ class AuthCookieInterceptor @Inject constructor(
 ) : Interceptor {
 
     override fun intercept(chain: Interceptor.Chain): Response {
+        val original = chain.request()
+        if (original.url.host != BaseUrlInterceptor.PLACEHOLDER_HOST) {
+            // External request — no Minstrel session cookie attached,
+            // and a 401 from this host does NOT clear the user's
+            // session. Pass through untouched.
+            return chain.proceed(original)
+        }
         val cookie = authStore.sessionCookie.value
-        val request = chain.request().newBuilder().apply {
+        val request = original.newBuilder().apply {
             if (!cookie.isNullOrEmpty()) header("Cookie", cookie)
         }.build()
 

android/app/src/main/java/com/fabledsword/minstrel/home/ui/HomeScreen.kt

@@ -288,7 +288,15 @@ class HomeViewModel @Inject constructor(
                 poolMessages.trySend("Mix isn't ready yet - try again in a moment")
                 return@launch
             }
-            val source = if (playlist.refreshable) "playlist:${playlist.systemVariant}" else null
+            // Drift #564: send the BARE systemVariant string, not
+            // "playlist:<variant>" — the server's rotation matcher
+            // (internal/playevents/writer.go systemPlaylistSources)
+            // keys on the bare variant. Web sends the bare form too
+            // (web/src/lib/components/PlaylistCard.svelte:83), so this
+            // brings Android into alignment. Wrong prefix here meant
+            // system-mix plays from Android Home never advanced the
+            // rotation.
+            val source = if (playlist.refreshable) playlist.systemVariant else null
             player.setQueue(tracks, initialIndex = 0, source = source)
         }.join()
     }

android/app/src/main/java/com/fabledsword/minstrel/player/PlayerController.kt

@@ -72,10 +72,19 @@ class PlayerController @Inject constructor(
      * failure (decoder, transport, EOS), and once when the player
      * reaches STATE_READY with a duration of zero / TIME_UNSET — the
      * "track loaded but has no audio" case the user sees as the
-     * player sitting frozen on a track. Conflated channel so back-
-     * pressure can't stall the player loop.
+     * player sitting frozen on a track.
+     *
+     * Drift #561: this was originally Channel.CONFLATED, which silently
+     * dropped every emission except the latest each time the reporter
+     * loop wasn't actively reading. A network blip that failed 5
+     * tracks back-to-back would surface only the last failure to the
+     * snackbar (the "Skipped 5 unplayable tracks" coalescing path was
+     * dead code) AND only POST one playback_errors row to the admin
+     * inbox instead of 5. Buffered so every burst event reaches the
+     * reporter; default capacity is 64 which is well above any real
+     * burst rate.
      */
-    private val playbackErrorEventsChannel = Channel<PlaybackErrorEvent>(Channel.CONFLATED)
+    private val playbackErrorEventsChannel = Channel<PlaybackErrorEvent>(Channel.BUFFERED)
     val playbackErrorEvents: Flow<PlaybackErrorEvent> = playbackErrorEventsChannel.receiveAsFlow()
 
     /**

android/app/src/main/java/com/fabledsword/minstrel/playlists/ui/PlaylistDetailScreen.kt

@@ -227,7 +227,16 @@ class PlaylistDetailViewModel @Inject constructor(
         val refs = tracks.toPlayableTrackRefs()
         if (refs.isEmpty()) return
         val startIndex = refs.indexOfFirst { it.id == startTrackId }.coerceAtLeast(0)
-        player.setQueue(refs, initialIndex = startIndex, source = "playlist:$playlistId")
+        // Drift #564: for refreshable system playlists, send the bare
+        // systemVariant string so the rotation matcher
+        // (systemPlaylistSources in playevents/writer.go) sees the
+        // play. User playlists keep the "playlist:<id>" tag for
+        // attribution but it doesn't trigger rotation (intentional —
+        // rotation only applies to system mixes).
+        val playlist = (internal.value as? PlaylistDetailUiState.Success)?.detail?.playlist
+        val source = playlist?.systemVariant?.takeIf { playlist.refreshable }
+            ?: "playlist:$playlistId"
+        player.setQueue(refs, initialIndex = startIndex, source = source)
     }
 }
 

android/app/src/test/java/com/fabledsword/minstrel/api/AuthCookieInterceptorTest.kt

@@ -45,12 +45,26 @@ class AuthCookieInterceptorTest {
             }
         authStore = AuthStore(dao, TestScope(UnconfinedTestDispatcher()))
 
+        // BaseUrlInterceptor rewrites placeholder.invalid → mock server.
+        // AuthCookieInterceptor scopes its attach + clear behavior to
+        // the placeholder host so external Coil image fetches don't get
+        // the Minstrel session cookie attached and don't trigger a
+        // session-clear on 401. Tests issue requests to
+        // http://placeholder.invalid/... so the auth interceptor sees
+        // the in-scope host, and BaseUrlInterceptor (running AFTER, so
+        // the auth interceptor sees the original host) rewrites the URL
+        // before transport.
+        authStore.setBaseUrl(server.url("/").toString())
         client =
             OkHttpClient.Builder()
                 .addInterceptor(AuthCookieInterceptor(authStore))
+                .addInterceptor(BaseUrlInterceptor(authStore))
                 .build()
     }
 
+    private fun placeholderUrl(path: String): String =
+        "http://${BaseUrlInterceptor.PLACEHOLDER_HOST}$path"
+
     @AfterEach
     fun teardown() {
         server.shutdown()
@@ -61,7 +75,7 @@ class AuthCookieInterceptorTest {
         authStore.setSessionCookie("session=abc123")
         server.enqueue(MockResponse().setResponseCode(200))
 
-        client.newCall(Request.Builder().url(server.url("/api/test")).build()).execute()
+        client.newCall(Request.Builder().url(placeholderUrl("/api/test")).build()).execute()
 
         val recorded = server.takeRequest()
         assertEquals("session=abc123", recorded.getHeader("Cookie"))
@@ -72,7 +86,7 @@ class AuthCookieInterceptorTest {
         authStore.setSessionCookie("session=expired")
         server.enqueue(MockResponse().setResponseCode(401))
 
-        client.newCall(Request.Builder().url(server.url("/api/test")).build()).execute()
+        client.newCall(Request.Builder().url(placeholderUrl("/api/test")).build()).execute()
 
         assertNull(authStore.sessionCookie.value)
     }
@@ -85,7 +99,7 @@ class AuthCookieInterceptorTest {
                 .addHeader("Set-Cookie", "session=newvalue; Path=/; HttpOnly"),
         )
 
-        client.newCall(Request.Builder().url(server.url("/api/login")).build()).execute()
+        client.newCall(Request.Builder().url(placeholderUrl("/api/login")).build()).execute()
 
         assertEquals("session=newvalue", authStore.sessionCookie.value)
     }
@@ -95,8 +109,41 @@ class AuthCookieInterceptorTest {
         authStore.setSessionCookie("session=existing")
         server.enqueue(MockResponse().setResponseCode(200))
 
-        client.newCall(Request.Builder().url(server.url("/api/anything")).build()).execute()
+        client.newCall(Request.Builder().url(placeholderUrl("/api/anything")).build()).execute()
 
         assertEquals("session=existing", authStore.sessionCookie.value)
     }
+
+    // Drift #568 regression guard: requests to external hosts must NOT
+    // carry the Minstrel session cookie even when the auth store has
+    // one. The shared OkHttpClient is also used by Coil for image
+    // fetches to artwork.musicbrainz.org and the like; leaking the
+    // session cookie to those hosts is a posture violation.
+    @Test
+    fun `does NOT attach cookie to non-placeholder host`() {
+        authStore.setSessionCookie("session=secret")
+        server.enqueue(MockResponse().setResponseCode(200))
+
+        // Request goes directly to the mock server's host:port — NOT
+        // through the placeholder sentinel — so the auth interceptor
+        // should pass it through untouched.
+        client.newCall(Request.Builder().url(server.url("/external/image.jpg")).build()).execute()
+
+        val recorded = server.takeRequest()
+        assertNull(recorded.getHeader("Cookie"))
+    }
+
+    // Drift #569 regression guard: a 401 from an external host must
+    // NOT wipe the user's Minstrel session. A misbehaving CDN or a
+    // Lidarr that's 401-ing on /MediaCover URLs used to silently sign
+    // the user out.
+    @Test
+    fun `does NOT clear cookie on 401 from non-placeholder host`() {
+        authStore.setSessionCookie("session=keep")
+        server.enqueue(MockResponse().setResponseCode(401))
+
+        client.newCall(Request.Builder().url(server.url("/external/image.jpg")).build()).execute()
+
+        assertEquals("session=keep", authStore.sessionCookie.value)
+    }
 }

internal/playevents/writer.go

@@ -69,11 +69,32 @@ func (w *Writer) RecordPlayStarted(
 }
 
 // systemPlaylistSources are the play_events.source values that count
-// against a system playlist's rotation (Fable #415). Add future
-// system-playlist kinds here as they ship (deep_cuts, rediscover, …).
+// against a system playlist's rotation (Fable #415). Mirrors the
+// `playlists_kind_variant_consistent` CHECK in migration
+// 0028_discovery_mix_variants.up.sql — every variant in that CHECK
+// list that ships as a refreshable system mix needs to be here so
+// the rotation reporter sees Android + web plays from that surface.
+//
+// Drift #563: this map drifted behind the migrations. It had only
+// for_you + discover but migrations 0021 + 0028 added 6 more
+// variants. Plays from Rediscover / Deep Cuts / Songs Like X /
+// New for You / On This Day / First Listens didn't advance the
+// per-user rotation, so "unplayed first" ordering staled on those
+// mixes — same tracks kept surfacing.
+//
+// Future variant additions should update this map AND the CHECK in
+// the matching migration in the same change; the
+// `db_check_constraint_for_new_variants` standing rule covers the
+// CHECK half.
 var systemPlaylistSources = map[string]bool{
-	"for_you":  true,
-	"discover": true,
+	"for_you":           true,
+	"discover":          true,
+	"deep_cuts":         true,
+	"rediscover":        true,
+	"new_for_you":       true,
+	"on_this_day":       true,
+	"first_listens":     true,
+	"songs_like_artist": true,
 }
 
 // RecordPlayStartedWithSource is RecordPlayStarted plus a `source`