Merge pull request #2527 from vitorpamplona/claude/remove-group-on-leave-JTVQb

Fix memory leak when leaving Marmot groups

amethyst/src/main/java/com/vitorpamplona/amethyst/model/Account.kt

@@ -2319,6 +2319,12 @@ class Account(
         }
 
         val outbound = manager.leaveGroup(nostrGroupId)
+        // manager.leaveGroup already wiped MLS state, relay subscriptions and
+        // the persisted message log. Drop the in-memory chatroom too — that
+        // releases the strong refs to the decrypted inner notes so LocalCache
+        // (which holds them weakly) can GC them, and the Notification feed
+        // (which iterates marmotGroupList.rooms) stops surfacing the group.
+        marmotGroupList.removeGroup(nostrGroupId)
         client.publish(outbound.signedEvent, groupRelays)
     }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/chats/marmotGroup/MarmotGroupInfoScreen.kt

@@ -316,7 +316,6 @@ fun MarmotGroupInfoScreen(
                 scope.launch(Dispatchers.IO) {
                     try {
                         accountViewModel.leaveMarmotGroup(nostrGroupId)
-                        accountViewModel.account.marmotGroupList.removeGroup(nostrGroupId)
                         nav.nav(Route.Message)
                     } catch (e: Exception) {
                         isLeaving = false

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/model/marmotGroups/MarmotGroupChatroom.kt

@@ -202,4 +202,21 @@ class MarmotGroupChatroom(
         changesFlow.get()?.tryEmit(ListChange.SetDeletion<Note>(toRemove))
         return toRemove
     }
+
+    /**
+     * Drop every message from this chatroom. Used when the local user leaves
+     * the group: cuts the strong references held in [messages] so the
+     * decrypted inner notes become eligible for GC out of LocalCache (which
+     * holds them weakly).
+     */
+    @Synchronized
+    fun clearAllMessagesSync(): Set<Note> {
+        val toRemove = messages
+        if (toRemove.isEmpty()) return toRemove
+        messages = emptySet()
+        newestMessage = null
+        unreadCount.value = 0
+        changesFlow.get()?.tryEmit(ListChange.SetDeletion<Note>(toRemove))
+        return toRemove
+    }
 }

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/model/marmotGroups/MarmotGroupList.kt

@@ -127,8 +127,15 @@ class MarmotGroupList(
         }
     }
 
+    /**
+     * Drop a group from the in-memory list. Also clears the chatroom's own
+     * message set and the note→group index: LocalCache holds notes weakly, so
+     * once these strong references go away the decrypted inner messages
+     * become eligible for GC and stop appearing in the Notification feed.
+     */
     fun removeGroup(nostrGroupId: HexKey) {
-        rooms.remove(nostrGroupId)
+        val chatroom = rooms.remove(nostrGroupId)
+        chatroom?.clearAllMessagesSync()?.forEach { noteToGroupIndex.remove(it.idHex) }
         _groupListChanges.tryEmit(nostrGroupId)
     }