Merge pull request #7877 from element-hq/bugfix/bma/sessionDelegatePerClient

Fix the wrong account being signed out when the session of another account is revoked

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

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2026 Element Creations Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.matrix.impl
+
+import org.matrix.rustcomponents.sdk.ClientSessionDelegate
+import org.matrix.rustcomponents.sdk.Session
+
+/**
+ * A [ClientSessionDelegate] which does nothing, to be used for the clients which are not associated to a stored session,
+ * for instance the temporary clients, or the clients used to perform a login. The session is only stored once the login
+ * is done, with a client created by [RustMatrixClientFactory.create], which uses a [RustClientSessionDelegate].
+ */
+internal object NoOpClientSessionDelegate : ClientSessionDelegate {
+    override fun saveSessionInKeychain(session: Session) = Unit
+
+    override fun retrieveSessionFromKeychain(userId: String): Session {
+        // This should never be called, as it's only used for multi-process setups
+        error("retrieveSessionFromKeychain should never be called for Android")
+    }
+}

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

@@ -37,6 +37,7 @@ private val loggerTag = LoggerTag("RustClientSessionDelegate")
  * It implements both [ClientSessionDelegate] and [ClientDelegate] to react to session data updates and auth errors.
  *
  * IMPORTANT: you must set the [client] property as soon as possible so [didReceiveAuthError] can work properly.
+ * Since [didReceiveAuthError] does not tell which session is concerned, each client must have its own instance.
  */
 class RustClientSessionDelegate(
     private val sessionStore: SessionStore,

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

@@ -33,6 +33,7 @@ import io.element.android.services.analytics.api.AnalyticsService
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.withContext
 import org.matrix.rustcomponents.sdk.ClientBuilder
+import org.matrix.rustcomponents.sdk.ClientSessionDelegate
 import org.matrix.rustcomponents.sdk.CrossProcessLockConfig
 import org.matrix.rustcomponents.sdk.RequestConfig
 import org.matrix.rustcomponents.sdk.Session
@@ -65,7 +66,11 @@ class RustMatrixClientFactory(
     private val clientBuilderEnterpriseHook: ClientBuilderEnterpriseHook,
     private val innerMatrixClientFactory: RustMatrixClient.Factory,
 ) {
-    private val sessionDelegate = RustClientSessionDelegate(
+    /**
+     * Create a new [RustClientSessionDelegate]. Each client must have its own instance, since the delegate
+     * keeps a reference to the client it handles the auth errors for.
+     */
+    private fun createSessionDelegate() = RustClientSessionDelegate(
         sessionStore = sessionStore,
         appCoroutineScope = appCoroutineScope,
         analyticsService = analyticsService,
@@ -86,11 +91,14 @@ class RustMatrixClientFactory(
             indexDirectory.deleteRecursively()
         }
 
+        // Use a dedicated delegate for this client, so that an auth error only affects this session
+        val sessionDelegate = createSessionDelegate()
         val client = getBaseClientBuilder(
             sessionPaths = sessionPaths,
             clientSecret = clientSecret,
             slidingSyncType = ClientBuilderSlidingSync.Restored,
             isMessageSearchAvailable = isMessageSearchAvailable,
+            sessionDelegate = sessionDelegate,
         )
             .homeserverUrl(sessionData.homeserverUrl)
             .enableAutomaticBackPagination(featureFlagService.isFeatureEnabled(FeatureFlags.AutomaticBackPagination))
@@ -144,6 +152,7 @@ class RustMatrixClientFactory(
         clientSecret: ClientSecret?,
         slidingSyncType: ClientBuilderSlidingSync,
         isMessageSearchAvailable: Boolean,
+        sessionDelegate: ClientSessionDelegate,
     ): ClientBuilder {
         return clientBuilderProvider.provide()
             .run {

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

@@ -35,6 +35,7 @@ class RustTemporaryMatrixClientFactory(
                 clientSecret = null,
                 slidingSyncType = ClientBuilderSlidingSync.Native,
                 isMessageSearchAvailable = false,
+                sessionDelegate = NoOpClientSessionDelegate,
             )
                 .serverName(formattedServerName)
                 .build()

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/auth/RustMatrixAuthenticationService.kt

@@ -34,6 +34,7 @@ import io.element.android.libraries.matrix.api.core.UserId
 import io.element.android.libraries.matrix.api.paths.SessionPaths
 import io.element.android.libraries.matrix.api.verification.SessionVerifiedStatus
 import io.element.android.libraries.matrix.impl.ClientBuilderSlidingSync
+import io.element.android.libraries.matrix.impl.NoOpClientSessionDelegate
 import io.element.android.libraries.matrix.impl.RustMatrixClientFactory
 import io.element.android.libraries.matrix.impl.RustTemporaryMatrixClient
 import io.element.android.libraries.matrix.impl.auth.qrlogin.QrErrorMapper
@@ -407,6 +408,7 @@ class RustMatrixAuthenticationService(
                 clientSecret = pendingKey,
                 slidingSyncType = ClientBuilderSlidingSync.Discovered,
                 isMessageSearchAvailable = isMessageSearchAvailable(),
+                sessionDelegate = NoOpClientSessionDelegate,
             )
             .config()
             .build()
@@ -440,6 +442,7 @@ class RustMatrixAuthenticationService(
                 clientSecret = pendingKey,
                 slidingSyncType = ClientBuilderSlidingSync.Discovered,
                 isMessageSearchAvailable = isMessageSearchAvailable(),
+                sessionDelegate = NoOpClientSessionDelegate,
             )
             .serverNameOrHomeserverUrl(baseUrlOrServerName)
             .build()

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClientFactoryTest.kt

@@ -15,6 +15,8 @@ import io.element.android.libraries.matrix.api.core.SessionId
 import io.element.android.libraries.matrix.api.paths.SessionPaths
 import io.element.android.libraries.matrix.api.scanner.ContentScanner
 import io.element.android.libraries.matrix.impl.auth.FakeProxyProvider
+import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiClient
+import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiClientBuilder
 import io.element.android.libraries.matrix.impl.room.FakeTimelineEventFilterFactory
 import io.element.android.libraries.matrix.impl.search.RustSearchBackfillService
 import io.element.android.libraries.matrix.impl.search.workmanager.SearchBackfillRequestBuilder
@@ -35,6 +37,7 @@ import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.runTest
 import org.junit.Test
 import org.matrix.rustcomponents.sdk.Client
+import org.matrix.rustcomponents.sdk.ClientDelegate
 import java.io.File
 import org.matrix.rustcomponents.sdk.SyncService as ClientSyncService
 
@@ -51,6 +54,46 @@ class RustMatrixClientFactoryTest {
         scheduleVacuumLambda.assertions().isCalledOnce()
         result.destroy()
     }
+
+    @Test
+    fun `an auth error on a client only invalidates its own session`() = runTest {
+        val aliceSessionId = "@alice:server.org"
+        val bobSessionId = "@bob:server.org"
+        val sessionStore = InMemorySessionStore(
+            initialList = listOf(
+                aSessionData(sessionId = aliceSessionId, isTokenValid = true),
+                aSessionData(sessionId = bobSessionId, isTokenValid = true),
+            ),
+            updateUserProfileResult = { _, _, _, _ -> },
+        )
+        val userIds = ArrayDeque(listOf(aliceSessionId, bobSessionId))
+        val delegates = mutableMapOf<String, ClientDelegate?>()
+        val sut = createRustMatrixClientFactory(
+            sessionStore = sessionStore,
+            workManagerScheduler = FakeWorkManagerScheduler(submitLambda = {}, cancelLambda = { _, _ -> }),
+            clientBuilderProvider = FakeClientBuilderProvider {
+                val userId = userIds.removeFirst()
+                FakeFfiClientBuilder(
+                    buildResult = {
+                        FakeFfiClient(
+                            userId = userId,
+                            withUtdHook = {},
+                            setDelegateResult = { delegates[userId] = it },
+                        )
+                    }
+                )
+            },
+        )
+        val aliceClient = sut.create(sessionStore.getSession(aliceSessionId)!!)
+        val bobClient = sut.create(sessionStore.getSession(bobSessionId)!!)
+
+        delegates.getValue(aliceSessionId)!!.didReceiveAuthError(isSoftLogout = false)
+
+        assertThat(sessionStore.getSession(aliceSessionId)!!.isTokenValid).isFalse()
+        assertThat(sessionStore.getSession(bobSessionId)!!.isTokenValid).isTrue()
+        aliceClient.destroy()
+        bobClient.destroy()
+    }
 }
 
 fun TestScope.createRustMatrixClientFactory(

libraries/matrix/impl/src/test/kotlin/io/element/android/libraries/matrix/impl/fixtures/fakes/FakeFfiClient.kt

@@ -76,6 +76,7 @@ class FakeFfiClient(
     private val contentScannerResult: () -> ContentScanner = { FakeFfiContentScanner() },
     private val runSearchBackfillResult: (SearchBackfillStrategy) -> TaskHandle = { lambdaError() },
     private val closeResult: () -> Unit = {},
+    private val setDelegateResult: (ClientDelegate?) -> Unit = {},
 ) : Client(NoHandle) {
     override fun userId(): String = userId
     override fun deviceId(): String = deviceId
@@ -85,7 +86,10 @@ class FakeFfiClient(
     override suspend fun getNotificationSettings(): NotificationSettings = notificationSettings
     override fun encryption(): Encryption = encryption
     override fun session(): Session = session
-    override fun setDelegate(delegate: ClientDelegate?): TaskHandle = FakeFfiTaskHandle()
+    override fun setDelegate(delegate: ClientDelegate?): TaskHandle {
+        setDelegateResult(delegate)
+        return FakeFfiTaskHandle()
+    }
     override suspend fun cachedAvatarUrl(): String? = null
     override suspend fun restoreSession(session: Session) = Unit
     override fun syncService(): SyncServiceBuilder = FakeFfiSyncServiceBuilder()