Remove verification listeners of logged out sessions

- Clear the listener when RustSessionVerificationService is destroyed.
- IncomingVerificationRequestObserver removes the listener of the clients which are not in the MatrixSessionCache anymore.
- Remove the sessions from the MatrixSessionCache when they are removed from the SessionStore (logout, account deactivation).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

appnav/src/main/kotlin/io/element/android/appnav/RootFlowNode.kt

@@ -84,6 +84,7 @@ import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.runningFold
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withTimeoutOrNull
 import kotlinx.parcelize.Parcelize
@@ -138,6 +139,7 @@ class RootFlowNode(
             }
         }
         observeIncomingVerificationRequests()
+        observeRemovedSessions()
         super.onBuilt()
     }
 
@@ -230,6 +232,22 @@ class RootFlowNode(
             }
     }
 
+    /**
+     * Remove from the cache the sessions which have been removed from the session store, for instance after a logout.
+     */
+    private fun observeRemovedSessions() {
+        sessionStore.sessionsFlow()
+            .map { sessions -> sessions.map { SessionId(it.userId) }.toSet() }
+            .runningFold(emptySet<SessionId>() to emptySet<SessionId>()) { (_, previous), current -> previous to current }
+            .onEach { (previous, current) ->
+                (previous - current).forEach { sessionId ->
+                    Timber.d("Session $sessionId removed, remove it from the cache")
+                    matrixSessionCache.remove(sessionId)
+                }
+            }
+            .launchIn(lifecycleScope)
+    }
+
     private fun observeIncomingVerificationRequests() {
         incomingVerificationRequestObserver.incomingVerificationRequests()
             .onEach(::onIncomingVerificationRequest)

appnav/src/main/kotlin/io/element/android/appnav/verification/IncomingVerificationRequestObserver.kt

@@ -9,6 +9,7 @@ package io.element.android.appnav.verification
 
 import dev.zacsweers.metro.Inject
 import io.element.android.appnav.session.MatrixSessionCache
+import io.element.android.libraries.core.coroutine.withPreviousValue
 import io.element.android.libraries.matrix.api.core.SessionId
 import io.element.android.libraries.matrix.api.verification.SessionVerificationServiceListener
 import io.element.android.libraries.matrix.api.verification.VerificationRequest
@@ -41,8 +42,13 @@ class IncomingVerificationRequestObserver(
      */
     fun incomingVerificationRequests(): Flow<IncomingVerificationRequestData> = channelFlow {
         launch {
-            matrixSessionCache.matrixClients.collect { matrixClients ->
+            matrixSessionCache.matrixClients.withPreviousValue().collect { (previousMatrixClients, matrixClients) ->
-                matrixClients.forEach { matrixClient ->
+                val previousMatrixClientSet = previousMatrixClients.orEmpty().toSet()
+                // Remove the listener of the clients which are not in the cache anymore
+                (previousMatrixClientSet - matrixClients.toSet()).forEach { matrixClient ->
+                    matrixClient.sessionVerificationService.setListener(null)
+                }
+                (matrixClients - previousMatrixClientSet).forEach { matrixClient ->
                     val sessionId = matrixClient.sessionId
                     matrixClient.sessionVerificationService.setListener(
                         object : SessionVerificationServiceListener {

appnav/src/test/kotlin/io/element/android/appnav/verification/IncomingVerificationRequestObserverTest.kt

@@ -63,6 +63,26 @@ class IncomingVerificationRequestObserverTest {
         assertThat(sessionVerificationService2.listener).isNull()
     }
 
+    @Test
+    fun `listener is removed when the session is removed from the cache`() = runTest {
+        val matrixSessionCache = createMatrixSessionCache()
+        val observer = IncomingVerificationRequestObserver(
+            matrixSessionCache = matrixSessionCache,
+            appForegroundStateService = FakeAppForegroundStateService(),
+        )
+        observer.incomingVerificationRequests().test {
+            matrixSessionCache.getOrRestore(A_SESSION_ID)
+            matrixSessionCache.getOrRestore(A_SESSION_ID_2)
+            runCurrent()
+            assertThat(sessionVerificationService1.listener).isNotNull()
+            assertThat(sessionVerificationService2.listener).isNotNull()
+            matrixSessionCache.remove(A_SESSION_ID)
+            runCurrent()
+            assertThat(sessionVerificationService1.listener).isNull()
+            assertThat(sessionVerificationService2.listener).isNotNull()
+        }
+    }
+
     @Test
     fun `incoming verification request is emitted when the app goes to foreground`() = runTest {
         val matrixSessionCache = createMatrixSessionCache()

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/verification/RustSessionVerificationService.kt

@@ -245,6 +245,7 @@ class RustSessionVerificationService(
 
     fun destroy() {
         Timber.d("Destroying RustSessionVerificationService")
+        listener = null
         verificationStateListenerTaskHandle.cancelAndDestroy()
         recoveryStateListenerTaskHandle.cancelAndDestroy()
         if (this::verificationController.isInitialized) {