Merge pull request #6978 from vector-im/feature/bma/null_room

Fix crash when opening an unknown room

changelog.d/6978.bugfix

@@ -0,0 +1 @@
+Fix crash when opening an unknown room

vector/src/main/java/im/vector/app/features/home/room/detail/TimelineFragment.kt

@@ -62,6 +62,7 @@ import com.airbnb.epoxy.EpoxyModel
 import com.airbnb.epoxy.OnModelBuildFinishedListener
 import com.airbnb.epoxy.addGlidePreloader
 import com.airbnb.epoxy.glidePreloader
+import com.airbnb.mvrx.Fail
 import com.airbnb.mvrx.args
 import com.airbnb.mvrx.fragmentViewModel
 import com.airbnb.mvrx.withState
@@ -161,6 +162,7 @@ import im.vector.app.features.home.room.detail.composer.SendMode
 import im.vector.app.features.home.room.detail.composer.boolean
 import im.vector.app.features.home.room.detail.composer.voice.VoiceMessageRecorderView
 import im.vector.app.features.home.room.detail.composer.voice.VoiceMessageRecorderView.RecordingUiState
+import im.vector.app.features.home.room.detail.error.RoomNotFound
 import im.vector.app.features.home.room.detail.readreceipts.DisplayReadReceiptsBottomSheet
 import im.vector.app.features.home.room.detail.timeline.TimelineEventController
 import im.vector.app.features.home.room.detail.timeline.action.EventSharedAction
@@ -992,9 +994,9 @@ class TimelineFragment :
         views.jumpToBottomView.debouncedClicks {
             timelineViewModel.handle(RoomDetailAction.ExitTrackingUnreadMessagesState)
             views.jumpToBottomView.visibility = View.INVISIBLE
-            if (!timelineViewModel.timeline.isLive) {
+            if (timelineViewModel.timeline?.isLive == false) {
                 scrollOnNewMessageCallback.forceScrollOnNextUpdate()
-                timelineViewModel.timeline.restartWithEventId(null)
+                timelineViewModel.timeline?.restartWithEventId(null)
             } else {
                 layoutManager.scrollToPosition(0)
             }
@@ -1224,12 +1226,12 @@ class TimelineFragment :
         }
     }
 
-    private fun handleSearchAction() {
+    private fun handleSearchAction() = withState(timelineViewModel) { state ->
         navigator.openSearch(
                 context = requireContext(),
                 roomId = timelineArgs.roomId,
-                roomDisplayName = timelineViewModel.getRoomSummary()?.displayName,
+                roomDisplayName = state.asyncRoomSummary()?.displayName,
-                roomAvatarUrl = timelineViewModel.getRoomSummary()?.avatarUrl
+                roomAvatarUrl = state.asyncRoomSummary()?.avatarUrl
         )
     }
 
@@ -1640,6 +1642,10 @@ class TimelineFragment :
 
     override fun invalidate() = withState(timelineViewModel, messageComposerViewModel) { mainState, messageComposerState ->
         invalidateOptionsMenu()
+        if (mainState.asyncRoomSummary is Fail) {
+            handleRoomSummaryFailure(mainState.asyncRoomSummary)
+            return@withState
+        }
         val summary = mainState.asyncRoomSummary()
         renderToolbar(summary)
         renderTypingMessageNotification(summary, mainState)
@@ -1695,6 +1701,23 @@ class TimelineFragment :
         updateLiveLocationIndicator(mainState.isSharingLiveLocation)
     }
 
+    private fun handleRoomSummaryFailure(asyncRoomSummary: Fail<RoomSummary>) {
+        views.roomNotFound.isVisible = true
+        views.roomNotFoundText.text = when (asyncRoomSummary.error) {
+            is RoomNotFound -> {
+                getString(
+                        R.string.timeline_error_room_not_found,
+                        if (vectorPreferences.developerMode()) {
+                            "\nDeveloper info: $timelineArgs"
+                        } else {
+                            ""
+                        }
+                )
+            }
+            else -> errorFormatter.toHumanReadable(asyncRoomSummary.error)
+        }
+    }
+
     private fun updateLiveLocationIndicator(isSharingLiveLocation: Boolean) {
         views.liveLocationStatusIndicator.isVisible = isSharingLiveLocation
     }
@@ -2520,15 +2543,19 @@ class TimelineFragment :
      * Navigate to Threads timeline for the specified rootThreadEventId
      * using the ThreadsActivity.
      */
-    private fun navigateToThreadTimeline(rootThreadEventId: String, startsThread: Boolean = false, showKeyboard: Boolean = false) {
+    private fun navigateToThreadTimeline(
+            rootThreadEventId: String,
+            startsThread: Boolean = false,
+            showKeyboard: Boolean = false,
+    ) = withState(timelineViewModel) { state ->
         analyticsTracker.capture(Interaction.Name.MobileRoomThreadSummaryItem.toAnalyticsInteraction())
         context?.let {
             val roomThreadDetailArgs = ThreadTimelineArgs(
                     startsThread = startsThread,
                     roomId = timelineArgs.roomId,
-                    displayName = timelineViewModel.getRoomSummary()?.displayName,
+                    displayName = state.asyncRoomSummary()?.displayName,
-                    avatarUrl = timelineViewModel.getRoomSummary()?.avatarUrl,
+                    avatarUrl = state.asyncRoomSummary()?.avatarUrl,
-                    roomEncryptionTrustLevel = timelineViewModel.getRoomSummary()?.roomEncryptionTrustLevel,
+                    roomEncryptionTrustLevel = state.asyncRoomSummary()?.roomEncryptionTrustLevel,
                     rootThreadEventId = rootThreadEventId,
                     showKeyboard = showKeyboard
             )
@@ -2559,14 +2586,14 @@ class TimelineFragment :
      * Navigate to Threads list for the current room
      * using the ThreadsActivity.
      */
-    private fun navigateToThreadList() {
+    private fun navigateToThreadList() = withState(timelineViewModel) { state ->
         analyticsTracker.capture(Interaction.Name.MobileRoomThreadListButton.toAnalyticsInteraction())
         context?.let {
             val roomThreadDetailArgs = ThreadTimelineArgs(
                     roomId = timelineArgs.roomId,
-                    displayName = timelineViewModel.getRoomSummary()?.displayName,
+                    displayName = state.asyncRoomSummary()?.displayName,
-                    roomEncryptionTrustLevel = timelineViewModel.getRoomSummary()?.roomEncryptionTrustLevel,
+                    roomEncryptionTrustLevel = state.asyncRoomSummary()?.roomEncryptionTrustLevel,
-                    avatarUrl = timelineViewModel.getRoomSummary()?.avatarUrl
+                    avatarUrl = state.asyncRoomSummary()?.avatarUrl
             )
             navigator.openThreadList(it, roomThreadDetailArgs)
         }

vector/src/main/java/im/vector/app/features/home/room/detail/TimelineViewModel.kt

@@ -48,6 +48,7 @@ import im.vector.app.features.call.webrtc.WebRtcCallManager
 import im.vector.app.features.createdirect.DirectRoomHelper
 import im.vector.app.features.crypto.keysrequest.OutboundSessionKeySharingStrategy
 import im.vector.app.features.crypto.verification.SupportedVerificationMethodsProvider
+import im.vector.app.features.home.room.detail.error.RoomNotFound
 import im.vector.app.features.home.room.detail.location.RedactLiveLocationShareEventUseCase
 import im.vector.app.features.home.room.detail.sticker.StickerPickerActionHandler
 import im.vector.app.features.home.room.detail.timeline.factory.TimelineFactory
@@ -93,6 +94,7 @@ import org.matrix.android.sdk.api.session.events.model.toContent
 import org.matrix.android.sdk.api.session.events.model.toModel
 import org.matrix.android.sdk.api.session.file.FileService
 import org.matrix.android.sdk.api.session.getRoom
+import org.matrix.android.sdk.api.session.room.Room
 import org.matrix.android.sdk.api.session.room.getStateEvent
 import org.matrix.android.sdk.api.session.room.getTimelineEvent
 import org.matrix.android.sdk.api.session.room.location.UpdateLiveLocationShareResult
@@ -143,16 +145,16 @@ class TimelineViewModel @AssistedInject constructor(
         private val cryptoConfig: CryptoConfig,
         buildMeta: BuildMeta,
         timelineFactory: TimelineFactory,
-        spaceStateHandler: SpaceStateHandler,
+        private val spaceStateHandler: SpaceStateHandler,
 ) : VectorViewModel<RoomDetailViewState, RoomDetailAction, RoomDetailViewEvents>(initialState),
         Timeline.Listener, ChatEffectManager.Delegate, CallProtocolsChecker.Listener, LocationSharingServiceConnection.Callback {
 
-    private val room = session.getRoom(initialState.roomId)!!
+    private val room = session.getRoom(initialState.roomId)
     private val eventId = initialState.eventId
     private val invisibleEventsSource = BehaviorDataSource<RoomDetailAction.TimelineEventTurnsInvisible>()
     private val visibleEventsSource = BehaviorDataSource<RoomDetailAction.TimelineEventTurnsVisible>()
     private var timelineEvents = MutableSharedFlow<List<TimelineEvent>>(0)
-    val timeline = timelineFactory.createTimeline(viewModelScope, room, eventId, initialState.rootThreadEventId)
+    val timeline: Timeline?
 
     // Same lifecycle than the ViewModel (survive to screen rotation)
     val previewUrlRetriever = PreviewUrlRetriever(session, viewModelScope, buildMeta)
@@ -181,9 +183,20 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     init {
+        // This method will take care of a null room to update the state.
+        observeRoomSummary()
+        if (room == null) {
+            timeline = null
+        } else {
+            // Nominal case, we have retrieved the room.
+            timeline = timelineFactory.createTimeline(viewModelScope, room, eventId, initialState.rootThreadEventId)
+            initSafe(room, timeline)
+        }
+    }
+
+    private fun initSafe(room: Room, timeline: Timeline) {
         timeline.start(initialState.rootThreadEventId)
         timeline.addListener(this)
-        observeRoomSummary()
         observeMembershipChanges()
         observeSummaryState()
         getUnreadState()
@@ -195,7 +208,6 @@ class TimelineViewModel @AssistedInject constructor(
         observeActiveRoomWidgets()
         observePowerLevel()
         setupPreviewUrlObservers()
-        room.getRoomSummaryLive()
         viewModelScope.launch(Dispatchers.IO) {
             tryOrNull { room.readService().markAsRead(ReadService.MarkAsReadParams.READ_RECEIPT) }
         }
@@ -266,6 +278,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun prepareForEncryption() {
+        if (room == null) return
         // check if there is not already a call made, or if there has been an error
         if (prepareToEncrypt.shouldLoad) {
             prepareToEncrypt = Loading()
@@ -282,6 +295,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun observePowerLevel() {
+        if (room == null) return
         PowerLevelsFlowFactory(room).createFlow()
                 .onEach {
                     val canInvite = PowerLevelsHelper(it).isUserAbleToInvite(session.myUserId)
@@ -330,6 +344,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun observeMyRoomMember() {
+        if (room == null) return
         val queryParams = roomMemberQueryParams {
             this.userId = QueryStringValue.Equals(session.myUserId, QueryStringValue.Case.SENSITIVE)
         }
@@ -345,6 +360,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun setupPreviewUrlObservers() {
+        if (room == null) return
         if (!vectorPreferences.showUrlPreviews()) {
             return
         }
@@ -373,6 +389,7 @@ class TimelineViewModel @AssistedInject constructor(
      * This is a local implementation has nothing to do with APIs.
      */
     private fun markThreadTimelineAsReadLocal() {
+        if (room == null) return
         initialState.rootThreadEventId?.let {
             session.coroutineScope.launch {
                 room.threadsLocalService().markThreadAsRead(it)
@@ -384,6 +401,7 @@ class TimelineViewModel @AssistedInject constructor(
      * Observe local unread threads.
      */
     private fun observeLocalThreadNotifications() {
+        if (room == null) return
         room.flow()
                 .liveLocalUnreadThreadList()
                 .execute {
@@ -401,10 +419,6 @@ class TimelineViewModel @AssistedInject constructor(
                 }
     }
 
-    fun getOtherUserIds() = room.roomSummary()?.otherMemberIds
-
-    fun getRoomSummary() = room.roomSummary()
-
     override fun handle(action: RoomDetailAction) {
         when (action) {
             is RoomDetailAction.ComposerFocusChange -> handleComposerFocusChange(action)
@@ -519,6 +533,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleSetNewAvatar(action: RoomDetailAction.SetAvatarAction) {
+        if (room == null) return
         viewModelScope.launch(Dispatchers.IO) {
             try {
                 room.stateService().updateAvatar(action.newAvatarUri, action.newAvatarFileName)
@@ -538,11 +553,13 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleJumpToReadReceipt(action: RoomDetailAction.JumpToReadReceipt) {
+        if (room == null) return
         room.readService().getUserReadReceipt(action.userId)
                 ?.let { handleNavigateToEvent(RoomDetailAction.NavigateToEvent(it, true)) }
     }
 
     private fun handleSendSticker(action: RoomDetailAction.SendSticker) {
+        if (room == null) return
         val content = initialState.rootThreadEventId?.let {
             action.stickerContent.copy(
                     relatesTo = RelationDefaultContent(
@@ -557,6 +574,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleStartCall(action: RoomDetailAction.StartCall) {
+        if (room == null) return
         viewModelScope.launch {
             room.roomSummary()?.otherMemberIds?.firstOrNull()?.let {
                 callManager.startOutgoingCall(room.roomId, it, action.isVideo)
@@ -602,7 +620,7 @@ class TimelineViewModel @AssistedInject constructor(
         _viewEvents.post(RoomDetailViewEvents.ShowWaitingView)
         viewModelScope.launch(Dispatchers.IO) {
             try {
-                val widget = jitsiService.createJitsiWidget(room.roomId, action.withVideo)
+                val widget = jitsiService.createJitsiWidget(initialState.roomId, action.withVideo)
                 _viewEvents.post(RoomDetailViewEvents.JoinJitsiConference(widget, action.withVideo))
             } catch (failure: Throwable) {
                 _viewEvents.post(RoomDetailViewEvents.ShowMessage(stringProvider.getString(R.string.failed_to_add_widget)))
@@ -621,7 +639,7 @@ class TimelineViewModel @AssistedInject constructor(
                 } else {
                     _viewEvents.post(RoomDetailViewEvents.ShowWaitingView)
                 }
-                session.widgetService().destroyRoomWidget(room.roomId, widgetId)
+                session.widgetService().destroyRoomWidget(initialState.roomId, widgetId)
                 // local echo
                 setState {
                     copy(
@@ -670,6 +688,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun stopTrackingUnreadMessages() {
+        if (room == null) return
         if (trackUnreadMessages.getAndSet(false)) {
             mostRecentDisplayedEvent?.root?.eventId?.also {
                 session.coroutineScope.launch {
@@ -686,10 +705,11 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     fun getMember(userId: String): RoomMemberSummary? {
-        return room.membershipService().getRoomMember(userId)
+        return room?.membershipService()?.getRoomMember(userId)
     }
 
     private fun handleComposerFocusChange(action: RoomDetailAction.ComposerFocusChange) {
+        if (room == null) return
         // Ensure outbound session keys
         if (room.roomCryptoService().isEncrypted()) {
             rawService.withElementWellKnown(viewModelScope, session.sessionParams) {
@@ -779,11 +799,12 @@ class TimelineViewModel @AssistedInject constructor(
     // PRIVATE METHODS *****************************************************************************
 
     private fun handleSendReaction(action: RoomDetailAction.SendReaction) {
+        if (room == null) return
         room.relationService().sendReaction(action.targetEventId, action.reaction)
     }
 
     private fun handleRedactEvent(action: RoomDetailAction.RedactAction) {
-        val event = room.getTimelineEvent(action.targetEventId) ?: return
+        val event = room?.getTimelineEvent(action.targetEventId) ?: return
         if (event.isLiveLocation()) {
             viewModelScope.launch {
                 redactLiveLocationShareEventUseCase.execute(event.root, room, action.reason)
@@ -794,6 +815,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleUndoReact(action: RoomDetailAction.UndoReaction) {
+        if (room == null) return
         viewModelScope.launch {
             tryOrNull {
                 room.relationService().undoReaction(action.targetEventId, action.reaction)
@@ -802,6 +824,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleUpdateQuickReaction(action: RoomDetailAction.UpdateQuickReactAction) {
+        if (room == null) return
         if (action.add) {
             room.relationService().sendReaction(action.targetEventId, action.selectedReaction)
         } else {
@@ -814,6 +837,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleSendMedia(action: RoomDetailAction.SendMedia) {
+        if (room == null) return
         room.sendService().sendMedias(
                 action.attachments,
                 action.compressBeforeSending,
@@ -823,6 +847,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleEventVisible(action: RoomDetailAction.TimelineEventTurnsVisible) {
+        if (room == null) return
         viewModelScope.launch(Dispatchers.Default) {
             if (action.event.root.sendState.isSent()) { // ignore pending/local events
                 visibleEventsSource.post(action)
@@ -850,6 +875,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleLoadMore(action: RoomDetailAction.LoadMoreTimelineEvents) {
+        if (timeline == null) return
         timeline.paginate(action.direction, PAGINATION_COUNT)
     }
 
@@ -857,7 +883,7 @@ class TimelineViewModel @AssistedInject constructor(
         notificationDrawerManager.updateEvents { it.clearMemberShipNotificationForRoom(initialState.roomId) }
         viewModelScope.launch {
             try {
-                session.roomService().leaveRoom(room.roomId)
+                session.roomService().leaveRoom(initialState.roomId)
             } catch (throwable: Throwable) {
                 _viewEvents.post(RoomDetailViewEvents.Failure(throwable, showInDialog = true))
             }
@@ -868,7 +894,7 @@ class TimelineViewModel @AssistedInject constructor(
         notificationDrawerManager.updateEvents { it.clearMemberShipNotificationForRoom(initialState.roomId) }
         viewModelScope.launch {
             try {
-                session.roomService().joinRoom(room.roomId)
+                session.roomService().joinRoom(initialState.roomId)
                 trackRoomJoined()
             } catch (throwable: Throwable) {
                 _viewEvents.post(RoomDetailViewEvents.Failure(throwable, showInDialog = true))
@@ -877,6 +903,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun trackRoomJoined() {
+        if (room == null) return
         val trigger = if (initialState.isInviteAlreadyAccepted) {
             JoinedRoom.Trigger.Invite
         } else {
@@ -934,6 +961,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleNavigateToEvent(action: RoomDetailAction.NavigateToEvent) {
+        if (timeline == null) return
         val targetEventId: String = action.eventId
         val indexOfEvent = timeline.getIndexOfEvent(targetEventId)
         if (indexOfEvent == null) {
@@ -947,6 +975,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleResendEvent(action: RoomDetailAction.ResendMessage) {
+        if (room == null) return
         val targetEventId = action.eventId
         room.getTimelineEvent(targetEventId)?.let {
             // State must be UNDELIVERED or Failed
@@ -965,6 +994,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleRemove(action: RoomDetailAction.RemoveFailedEcho) {
+        if (room == null) return
         val targetEventId = action.eventId
         room.getTimelineEvent(targetEventId)?.let {
             // State must be UNDELIVERED or Failed
@@ -977,6 +1007,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleCancel(action: RoomDetailAction.CancelSend) {
+        if (room == null) return
         if (action.force) {
             room.sendService().cancelSend(action.eventId)
             return
@@ -993,14 +1024,17 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleResendAll() {
+        if (room == null) return
         room.sendService().resendAllFailedMessages()
     }
 
     private fun handleRemoveAllFailedMessages() {
+        if (room == null) return
         room.sendService().cancelAllFailedMessages()
     }
 
     private fun observeEventDisplayedActions() {
+        if (room == null) return
         // We are buffering scroll events for one second
         // and keep the most recent one to set the read receipt on.
 
@@ -1032,9 +1066,10 @@ class TimelineViewModel @AssistedInject constructor(
      * Returns the index of event in the timeline.
      * Returns Int.MAX_VALUE if not found
      */
-    private fun TimelineEvent.indexOfEvent(): Int = timeline.getIndexOfEvent(eventId) ?: Int.MAX_VALUE
+    private fun TimelineEvent.indexOfEvent(): Int = timeline?.getIndexOfEvent(eventId) ?: Int.MAX_VALUE
 
     private fun handleMarkAllAsRead() {
+        if (room == null) return
         setState { copy(unreadState = UnreadState.HasNoUnread) }
         viewModelScope.launch {
             tryOrNull { room.readService().markAsRead(ReadService.MarkAsReadParams.BOTH) }
@@ -1042,6 +1077,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleReportContent(action: RoomDetailAction.ReportContent) {
+        if (room == null) return
         viewModelScope.launch {
             val event = try {
                 room.reportingService().reportContent(action.eventId, -100, action.reason)
@@ -1070,11 +1106,11 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleAcceptVerification(action: RoomDetailAction.AcceptVerificationRequest) {
-        Timber.v("## SAS handleAcceptVerification ${action.otherUserId},  roomId:${room.roomId}, txId:${action.transactionId}")
+        Timber.v("## SAS handleAcceptVerification ${action.otherUserId},  roomId:${initialState.roomId}, txId:${action.transactionId}")
         if (session.cryptoService().verificationService().readyPendingVerificationInDMs(
                         supportedVerificationMethodsProvider.provide(),
                         action.otherUserId,
-                        room.roomId,
+                        initialState.roomId,
                         action.transactionId
                 )) {
             _viewEvents.post(RoomDetailViewEvents.ActionSuccess(action))
@@ -1087,7 +1123,7 @@ class TimelineViewModel @AssistedInject constructor(
         session.cryptoService().verificationService().declineVerificationRequestInDMs(
                 action.otherUserId,
                 action.transactionId,
-                room.roomId
+                initialState.roomId
         )
     }
 
@@ -1098,7 +1134,7 @@ class TimelineViewModel @AssistedInject constructor(
 
     private fun handleResumeRequestVerification(action: RoomDetailAction.ResumeVerification) {
         // Check if this request is still active and handled by me
-        session.cryptoService().verificationService().getExistingVerificationRequestInRoom(room.roomId, action.transactionId)?.let {
+        session.cryptoService().verificationService().getExistingVerificationRequestInRoom(initialState.roomId, action.transactionId)?.let {
             if (it.handledByOtherSession) return
             if (!it.isFinished) {
                 _viewEvents.post(
@@ -1113,6 +1149,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleReRequestKeys(action: RoomDetailAction.ReRequestKeys) {
+        if (room == null) return
         // Check if this request is still active and handled by me
         room.getTimelineEvent(action.eventId)?.let {
             session.cryptoService().reRequestRoomKeyForEvent(it.root)
@@ -1121,6 +1158,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleTapOnFailedToDecrypt(action: RoomDetailAction.TapOnFailedToDecrypt) {
+        if (room == null) return
         room.getTimelineEvent(action.eventId)?.let {
             val code = when (it.root.mCryptoError) {
                 MXCryptoError.ErrorType.KEYS_WITHHELD -> {
@@ -1134,6 +1172,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleVoteToPoll(action: RoomDetailAction.VoteToPoll) {
+        if (room == null) return
         // Do not allow to vote unsent local echo of the poll event
         if (LocalEcho.isLocalEchoId(action.eventId)) return
         // Do not allow to vote the same option twice
@@ -1146,6 +1185,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun handleEndPoll(eventId: String) {
+        if (room == null) return
         room.sendService().endPoll(eventId)
     }
 
@@ -1165,7 +1205,7 @@ class TimelineViewModel @AssistedInject constructor(
 
     private fun handleStopLiveLocationSharing() {
         viewModelScope.launch {
-            val result = stopLiveLocationShareUseCase.execute(room.roomId)
+            val result = stopLiveLocationShareUseCase.execute(initialState.roomId)
             if (result is UpdateLiveLocationShareResult.Failure) {
                 _viewEvents.post(RoomDetailViewEvents.Failure(throwable = result.error, showInDialog = true))
             }
@@ -1173,6 +1213,14 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun observeRoomSummary() {
+        if (room == null) {
+            Timber.w("Warning, room with Id ${initialState.roomId} is not found.")
+            setState {
+                copy(
+                        asyncRoomSummary = Fail(RoomNotFound())
+                )
+            }
+        } else {
             room.flow().liveRoomSummary()
                     .unwrap()
                     .execute { async ->
@@ -1181,8 +1229,10 @@ class TimelineViewModel @AssistedInject constructor(
                         )
                     }
         }
+    }
 
     private fun getUnreadState() {
+        if (room == null) return
         combine(
                 timelineEvents,
                 room.flow().liveRoomSummary().unwrap()
@@ -1207,6 +1257,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun computeUnreadState(events: List<TimelineEvent>, roomSummary: RoomSummary): UnreadState {
+        if (timeline == null) return UnreadState.Unknown
         if (events.isEmpty()) return UnreadState.Unknown
         val readMarkerIdSnapshot = roomSummary.readMarkerId ?: return UnreadState.Unknown
         val firstDisplayableEventIndex = timeline.getIndexOfEvent(readMarkerIdSnapshot)
@@ -1253,6 +1304,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     private fun observeSummaryState() {
+        if (room == null) return
         onAsync(RoomDetailViewState::asyncRoomSummary) { summary ->
             setState {
                 val typingMessage = typingHelper.getTypingMessage(summary.typingUsers)
@@ -1296,6 +1348,7 @@ class TimelineViewModel @AssistedInject constructor(
      */
     private var threadPermalinkHandled = false
     private fun navigateToThreadEventIfNeeded(snapshot: List<TimelineEvent>) {
+        if (timeline == null) return
         if (eventId != null && initialState.rootThreadEventId != null) {
             // When we have a permalink and we are in a thread timeline
             if (snapshot.firstOrNull { it.eventId == eventId } != null && !threadPermalinkHandled) {
@@ -1318,6 +1371,7 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     override fun onTimelineFailure(throwable: Throwable) {
+        if (timeline == null) return
         // If we have a critical timeline issue, we get back to live.
         timeline.restartWithEventId(null)
         _viewEvents.post(RoomDetailViewEvents.Failure(throwable))
@@ -1343,11 +1397,11 @@ class TimelineViewModel @AssistedInject constructor(
     }
 
     override fun onCleared() {
-        timeline.dispose()
+        timeline?.dispose()
-        timeline.removeAllListeners()
+        timeline?.removeAllListeners()
-        decryptionFailureTracker.onTimeLineDisposed(room.roomId)
+        decryptionFailureTracker.onTimeLineDisposed(initialState.roomId)
         if (vectorPreferences.sendTypingNotifs()) {
-            room.typingService().userStopsTyping()
+            room?.typingService()?.userStopsTyping()
         }
         chatEffectManager.delegate = null
         chatEffectManager.dispose()

vector/src/main/java/im/vector/app/features/home/room/detail/error/RoomNotFound.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2022 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.vector.app.features.home.room.detail.error
+
+class RoomNotFound : Throwable()

vector/src/main/res/layout/fragment_timeline.xml

@@ -194,4 +194,47 @@
         android:background="?vctr_chat_effect_snow_background"
         android:visibility="invisible" />
 
+    <!-- Room not found layout -->
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@+id/roomNotFound"
+        android:layout_width="0dp"
+        android:layout_height="0dp"
+        android:background="?android:colorBackground"
+        android:elevation="10dp"
+        android:visibility="gone"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        tools:visibility="gone">
+
+        <ImageView
+            android:id="@+id/roomNotFoundIcon"
+            android:layout_width="60dp"
+            android:layout_height="60dp"
+            android:importantForAccessibility="no"
+            android:src="@drawable/ic_alert_triangle"
+            app:layout_constraintBottom_toTopOf="@id/roomNotFoundText"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintVertical_chainStyle="packed" />
+
+        <TextView
+            android:id="@+id/roomNotFoundText"
+            style="@style/Widget.Vector.TextView.Subtitle"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginTop="@dimen/layout_vertical_margin"
+            android:gravity="center"
+            android:paddingHorizontal="16dp"
+            android:text="@string/timeline_error_room_not_found"
+            android:textColor="?vctr_content_primary"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:layout_constraintEnd_toEndOf="parent"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintTop_toBottomOf="@id/roomNotFoundIcon" />
+
+    </androidx.constraintlayout.widget.ConstraintLayout>
+
 </androidx.constraintlayout.widget.ConstraintLayout>

vector/src/main/res/values/strings.xml

@@ -1349,6 +1349,9 @@
     <string name="settings_labs_native_camera_summary">Start the system camera instead of the custom camera screen.</string>
     <string name="widget_integration_review_terms">To continue you need to accept the Terms of this service.</string>
 
+    <!-- Room not found. %s will contain some debug info in developer mode.  -->
+    <string name="timeline_error_room_not_found">Sorry, this room has not been found.\nPlease retry later.%s</string>
+
     <!-- share keys -->
     <string name="you_added_a_new_device">You added a new session \'%s\', which is requesting encryption keys.</string>
     <string name="you_added_a_new_device_with_info">A new session is requesting encryption keys.\nSession name: %1$s\nLast seen: %2$s\nIf you didn’t log in on another session, ignore this request.</string>