Stop deleting the session data of a logged in account on the next login

sessionPaths keeps pointing at the directories of the account which has
just been logged in, and it was never reset. Adding another account
calls setHomeserver(), whose rotateSessionPath() starts by deleting the
directories of the previous sessionPaths, so the file and cache
directories of the first account were wiped.

finalizeClientCreation() now forgets the session paths once the login
succeeded. It is done there rather than in clear() on purpose: after a
failed attempt the directories are orphaned and must still be deleted by
the rotateSessionPath() of the next attempt.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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

@@ -386,6 +386,10 @@ class RustMatrixAuthenticationService(
         newMatrixClientObservers.forEach { it.invoke(matrixClient) }
         sessionStore.addSession(sessionData)
 
+        // The session paths now hold the data of the account which has just been logged in, so forget
+        // them: they must not be deleted by the rotateSessionPath() of the next login attempt.
+        sessionPaths = null
+
         return SessionId(sessionData.userId)
     }
 

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

@@ -15,6 +15,7 @@ import io.element.android.libraries.matrix.api.core.SessionId
 import io.element.android.libraries.matrix.impl.auth.FakeProxyProvider
 import io.element.android.libraries.matrix.impl.room.FakeTimelineEventFilterFactory
 import io.element.android.libraries.matrix.impl.storage.FakeSqliteStoreBuilderProvider
+import io.element.android.libraries.matrix.impl.storage.SqliteStoreBuilderProvider
 import io.element.android.libraries.network.useragent.SimpleUserAgentProvider
 import io.element.android.libraries.sessionstorage.api.SessionStore
 import io.element.android.libraries.sessionstorage.test.InMemorySessionStore
@@ -52,6 +53,7 @@ fun TestScope.createRustMatrixClientFactory(
     ),
     clientBuilderProvider: ClientBuilderProvider = FakeClientBuilderProvider(),
     workManagerScheduler: FakeWorkManagerScheduler = FakeWorkManagerScheduler(),
+    sqliteStoreBuilderProvider: SqliteStoreBuilderProvider = FakeSqliteStoreBuilderProvider(),
 ) = RustMatrixClientFactory(
     cacheDirectory = cacheDirectory,
     appCoroutineScope = backgroundScope,
@@ -64,7 +66,7 @@ fun TestScope.createRustMatrixClientFactory(
     featureFlagService = FakeFeatureFlagService(),
     timelineEventFilterFactory = FakeTimelineEventFilterFactory(),
     clientBuilderProvider = clientBuilderProvider,
-    sqliteStoreBuilderProvider = FakeSqliteStoreBuilderProvider(),
+    sqliteStoreBuilderProvider = sqliteStoreBuilderProvider,
     workManagerScheduler = workManagerScheduler,
     clientBuilderEnterpriseHook = FakeClientBuilderEnterpriseHook(),
 )

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

@@ -12,6 +12,7 @@ import com.google.common.truth.Truth.assertThat
 import io.element.android.features.enterprise.api.EnterpriseService
 import io.element.android.features.enterprise.test.FakeEnterpriseService
 import io.element.android.libraries.featureflag.test.FakeFeatureFlagService
+import io.element.android.libraries.matrix.api.paths.SessionPaths
 import io.element.android.libraries.matrix.impl.ClientBuilderProvider
 import io.element.android.libraries.matrix.impl.FakeClientBuilderProvider
 import io.element.android.libraries.matrix.impl.auth.qrlogin.SdkQrCodeLoginData
@@ -22,6 +23,10 @@ import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiHomeserver
 import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiLoginWithQrCodeHandler
 import io.element.android.libraries.matrix.impl.fixtures.fakes.FakeFfiQrCodeData
 import io.element.android.libraries.matrix.impl.paths.SessionPathsFactory
+import io.element.android.libraries.matrix.impl.storage.FakeSqliteStoreBuilder
+import io.element.android.libraries.matrix.impl.storage.FakeSqliteStoreBuilderProvider
+import io.element.android.libraries.matrix.impl.storage.SqliteStoreBuilder
+import io.element.android.libraries.matrix.impl.storage.SqliteStoreBuilderProvider
 import io.element.android.libraries.matrix.test.A_HOMESERVER_URL
 import io.element.android.libraries.matrix.test.A_USER_ID
 import io.element.android.libraries.matrix.test.auth.FakeOAuthRedirectUrlProvider
@@ -33,13 +38,18 @@ import io.element.android.tests.testutils.lambda.lambdaRecorder
 import io.element.android.tests.testutils.testCoroutineDispatchers
 import kotlinx.coroutines.test.TestScope
 import kotlinx.coroutines.test.runTest
+import org.junit.Rule
 import org.junit.Test
+import org.junit.rules.TemporaryFolder
 import org.matrix.rustcomponents.sdk.Client
 import org.matrix.rustcomponents.sdk.ClientBuilder
 import org.matrix.rustcomponents.sdk.HumanQrLoginException
 import java.io.File
 
 class RustMatrixAuthenticationServiceTest {
+    @get:Rule
+    val temporaryFolder = TemporaryFolder()
+
     @Test
     fun `setHomeserver is successful`() = runTest {
         val sut = createRustMatrixAuthenticationService(
@@ -177,21 +187,89 @@ class RustMatrixAuthenticationServiceTest {
         override fun provide(): ClientBuilder = FakeFfiClientBuilder(buildResult = clients[index++])
     }
 
+    @Test
+    fun `a new login does not delete the session data of the account which has just been logged in`() = runTest {
+        val storeBuilderProvider = SessionDirectoryCreatingSqliteStoreBuilderProvider()
+        val sut = createRustMatrixAuthenticationService(
+            clientBuilderProvider = FakeSequentialClientBuilderProvider(
+                { aLoginFakeFfiClient() },
+                { FakeFfiClient(withUtdHook = {}) },
+                { aLoginFakeFfiClient() },
+            ),
+            sessionPathsFactory = SessionPathsFactory(temporaryFolder.newFolder("base"), temporaryFolder.newFolder("cache")),
+            sqliteStoreBuilderProvider = storeBuilderProvider,
+        )
+
+        assertThat(sut.setHomeserver("matrix.org").isSuccess).isTrue()
+        assertThat(sut.login("alice", "password").getOrNull()).isEqualTo(A_USER_ID)
+        val loggedInSessionPaths = storeBuilderProvider.providedSessionPaths.first()
+
+        // Adding another account rotates the session paths, which must not touch the previous account.
+        assertThat(sut.setHomeserver("matrix.org").isSuccess).isTrue()
+
+        assertThat(loggedInSessionPaths.fileDirectory.exists()).isTrue()
+        assertThat(loggedInSessionPaths.cacheDirectory.exists()).isTrue()
+    }
+
+    @Test
+    fun `a new login deletes the session data of a previous failed login attempt`() = runTest {
+        val storeBuilderProvider = SessionDirectoryCreatingSqliteStoreBuilderProvider()
+        val sut = createRustMatrixAuthenticationService(
+            clientBuilderProvider = FakeSequentialClientBuilderProvider(
+                { aLoginFakeFfiClient() },
+                { throw IllegalStateException("Failed to build the client of the session") },
+                { aLoginFakeFfiClient() },
+            ),
+            sessionPathsFactory = SessionPathsFactory(temporaryFolder.newFolder("base"), temporaryFolder.newFolder("cache")),
+            sqliteStoreBuilderProvider = storeBuilderProvider,
+        )
+
+        assertThat(sut.setHomeserver("matrix.org").isSuccess).isTrue()
+        assertThat(sut.login("alice", "password").isFailure).isTrue()
+        val abandonedSessionPaths = storeBuilderProvider.providedSessionPaths.first()
+
+        assertThat(sut.setHomeserver("matrix.org").isSuccess).isTrue()
+
+        assertThat(abandonedSessionPaths.fileDirectory.exists()).isFalse()
+        assertThat(abandonedSessionPaths.cacheDirectory.exists()).isFalse()
+    }
+
+    private fun aLoginFakeFfiClient() = FakeFfiClient(
+        homeserverLoginDetailsResult = { FakeFfiHomeserverLoginDetails() },
+        loginResult = { _, _ -> },
+    )
+
+    /**
+     * A [SqliteStoreBuilderProvider] which creates the session directories, like the SDK does when it
+     * opens its stores, and records them so that a test can assert on their lifecycle.
+     */
+    private class SessionDirectoryCreatingSqliteStoreBuilderProvider : SqliteStoreBuilderProvider {
+        val providedSessionPaths = mutableListOf<SessionPaths>()
+
+        override fun provide(sessionPaths: SessionPaths): SqliteStoreBuilder {
+            sessionPaths.fileDirectory.mkdirs()
+            sessionPaths.cacheDirectory.mkdirs()
+            providedSessionPaths.add(sessionPaths)
+            return FakeSqliteStoreBuilder()
+        }
+    }
+
     private fun TestScope.createRustMatrixAuthenticationService(
         sessionStore: SessionStore = InMemorySessionStore(updateUserProfileResult = { _, _, _ -> }),
         clientBuilderProvider: ClientBuilderProvider = FakeClientBuilderProvider(),
         enterpriseService: EnterpriseService = FakeEnterpriseService(),
+        sessionPathsFactory: SessionPathsFactory = SessionPathsFactory(File("/base"), File("/cache")),
+        sqliteStoreBuilderProvider: SqliteStoreBuilderProvider = FakeSqliteStoreBuilderProvider(),
     ): RustMatrixAuthenticationService {
-        val baseDirectory = File("/base")
-        val cacheDirectory = File("/cache")
         val rustMatrixClientFactory = createRustMatrixClientFactory(
-            cacheDirectory = cacheDirectory,
+            cacheDirectory = File("/cache"),
             sessionStore = sessionStore,
             clientBuilderProvider = clientBuilderProvider,
             workManagerScheduler = FakeWorkManagerScheduler(submitLambda = {}),
+            sqliteStoreBuilderProvider = sqliteStoreBuilderProvider,
         )
         return RustMatrixAuthenticationService(
-            sessionPathsFactory = SessionPathsFactory(baseDirectory, cacheDirectory),
+            sessionPathsFactory = sessionPathsFactory,
             coroutineDispatchers = testCoroutineDispatchers(),
             sessionStore = sessionStore,
             rustMatrixClientFactory = rustMatrixClientFactory,