Handle error in the thread list request.

library/ui-strings/src/main/res/values/strings.xml

@@ -794,6 +794,7 @@
     <string name="thread_list_modal_my_threads_subtitle">Shows all threads you’ve participated in</string>
     <string name="thread_list_empty_title">Keep discussions organized with threads</string>
     <string name="thread_list_empty_subtitle">Threads help keep your conversations on-topic and easy to track.</string>
+    <string name="thread_list_not_available">You\'re homeserver does not support listing threads yet.</string>
     <!-- Parameter %s will be replaced by the value of string reply_in_thread -->
     <string name="thread_list_empty_notice">Tip: Long tap a message and use “%s”.</string>
     <string name="search_thread_from_a_thread">From a Thread</string>

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/failure/Extensions.kt

@@ -25,6 +25,9 @@ import java.io.IOException
 import java.net.UnknownHostException
 import javax.net.ssl.HttpsURLConnection
 
+fun Throwable.is400() = this is Failure.ServerError &&
+        httpCode == HttpsURLConnection.HTTP_BAD_REQUEST
+
 fun Throwable.is401() = this is Failure.ServerError &&
         httpCode == HttpsURLConnection.HTTP_UNAUTHORIZED && /* 401 */
         error.code == MatrixError.M_UNAUTHORIZED

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/threads/FetchThreadsResult.kt

@@ -19,5 +19,4 @@ package org.matrix.android.sdk.api.session.room.threads
 sealed class FetchThreadsResult {
     data class ShouldFetchMore(val nextBatch: String) : FetchThreadsResult()
     object ReachedEnd : FetchThreadsResult()
-    object Failed : FetchThreadsResult()
 }

vector/src/main/java/im/vector/app/features/home/room/threads/list/viewmodel/ThreadListViewActions.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2023 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.threads.list.viewmodel
+
+import im.vector.app.core.platform.VectorViewModelAction
+
+sealed interface ThreadListViewActions : VectorViewModelAction {
+    object TryAgain : ThreadListViewActions
+}

vector/src/main/java/im/vector/app/features/home/room/threads/list/viewmodel/ThreadListViewEvents.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2023 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.threads.list.viewmodel
+
+import im.vector.app.core.platform.VectorViewEvents
+
+sealed interface ThreadListViewEvents : VectorViewEvents {
+    data class ShowError(val throwable: Throwable) : ThreadListViewEvents
+}

vector/src/main/java/im/vector/app/features/home/room/threads/list/viewmodel/ThreadListViewModel.kt

@@ -27,8 +27,6 @@ import com.airbnb.mvrx.ViewModelContext
 import dagger.assisted.Assisted
 import dagger.assisted.AssistedFactory
 import dagger.assisted.AssistedInject
-import im.vector.app.core.platform.EmptyAction
-import im.vector.app.core.platform.EmptyViewEvents
 import im.vector.app.core.platform.VectorViewModel
 import im.vector.app.features.analytics.AnalyticsTracker
 import im.vector.app.features.analytics.extensions.toAnalyticsInteraction
@@ -52,7 +50,7 @@ class ThreadListViewModel @AssistedInject constructor(
         @Assisted val initialState: ThreadListViewState,
         private val analyticsTracker: AnalyticsTracker,
         private val session: Session,
-) : VectorViewModel<ThreadListViewState, EmptyAction, EmptyViewEvents>(initialState) {
+) : VectorViewModel<ThreadListViewState, ThreadListViewActions, ThreadListViewEvents>(initialState) {
 
     private val room = session.getRoom(initialState.roomId)
 
@@ -93,7 +91,17 @@ class ThreadListViewModel @AssistedInject constructor(
         fetchAndObserveThreads()
     }
 
-    override fun handle(action: EmptyAction) {}
+    override fun handle(action: ThreadListViewActions) {
+        when (action) {
+            ThreadListViewActions.TryAgain -> handleTryAgain()
+        }
+    }
+
+    private fun handleTryAgain() {
+        viewModelScope.launch {
+            fetchNextPage()
+        }
+    }
 
     /**
      * Observing thread list with respect to homeserver capabilities.
@@ -181,21 +189,23 @@ class ThreadListViewModel @AssistedInject constructor(
             true -> ThreadFilter.PARTICIPATED
             false -> ThreadFilter.ALL
         }
-        room?.threadsService()?.fetchThreadList(
+        try {
-                nextBatchId = nextBatchId,
+            room?.threadsService()?.fetchThreadList(
-                limit = defaultPagedListConfig.pageSize,
+                    nextBatchId = nextBatchId,
-                filter = filter,
+                    limit = defaultPagedListConfig.pageSize,
-        ).let { result ->
+                    filter = filter,
-            when (result) {
+            )?.let { result ->
-                is FetchThreadsResult.ReachedEnd -> {
+                when (result) {
-                    hasReachedEnd = true
+                    is FetchThreadsResult.ReachedEnd -> {
-                }
+                        hasReachedEnd = true
-                is FetchThreadsResult.ShouldFetchMore -> {
+                    }
-                    nextBatchId = result.nextBatch
+                    is FetchThreadsResult.ShouldFetchMore -> {
-                }
+                        nextBatchId = result.nextBatch
-                else -> {
+                    }
                 }
             }
+        } catch (throwable: Throwable) {
+            _viewEvents.post(ThreadListViewEvents.ShowError(throwable))
         }
     }
 }

vector/src/main/java/im/vector/app/features/home/room/threads/list/views/ThreadListFragment.kt

@@ -26,6 +26,7 @@ import androidx.core.view.isVisible
 import com.airbnb.mvrx.args
 import com.airbnb.mvrx.fragmentViewModel
 import com.airbnb.mvrx.withState
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import dagger.hilt.android.AndroidEntryPoint
 import im.vector.app.R
 import im.vector.app.core.extensions.cleanup
@@ -41,10 +42,14 @@ import im.vector.app.features.home.room.threads.arguments.ThreadListArgs
 import im.vector.app.features.home.room.threads.arguments.ThreadTimelineArgs
 import im.vector.app.features.home.room.threads.list.viewmodel.ThreadListController
 import im.vector.app.features.home.room.threads.list.viewmodel.ThreadListPagedController
+import im.vector.app.features.home.room.threads.list.viewmodel.ThreadListViewActions
+import im.vector.app.features.home.room.threads.list.viewmodel.ThreadListViewEvents
 import im.vector.app.features.home.room.threads.list.viewmodel.ThreadListViewModel
 import im.vector.app.features.home.room.threads.list.viewmodel.ThreadListViewState
 import im.vector.app.features.rageshake.BugReporter
 import im.vector.app.features.rageshake.ReportType
+import org.matrix.android.sdk.api.failure.is400
+import org.matrix.android.sdk.api.failure.is404
 import org.matrix.android.sdk.api.session.room.threads.model.ThreadSummary
 import org.matrix.android.sdk.api.session.room.timeline.TimelineEvent
 import org.matrix.android.sdk.api.util.MatrixItem
@@ -126,11 +131,45 @@ class ThreadListFragment :
             views.threadListRecyclerView.configureWith(legacyThreadListController, TimelineItemAnimator(), hasFixedSize = false)
             legacyThreadListController.listener = this
         }
+        observeViewEvents()
+    }
+
+    private fun observeViewEvents() {
+        threadListViewModel.observeViewEvents {
+            when (it) {
+                is ThreadListViewEvents.ShowError -> handleShowError(it)
+            }
+        }
+    }
+
+    private fun handleShowError(event: ThreadListViewEvents.ShowError) {
+        val error = event.throwable
+        MaterialAlertDialogBuilder(requireActivity())
+                .setTitle(R.string.dialog_title_error)
+                .also {
+                    if (error.is400() || error.is404()) {
+                        // Outdated Homeserver
+                        it.setMessage(R.string.thread_list_not_available)
+                        it.setPositiveButton(R.string.ok) { _, _ ->
+                            requireActivity().finish()
+                        }
+                    } else {
+                        // Other error, can retry
+                        // (Can happen on first request or on pagination request)
+                        it.setMessage(errorFormatter.toHumanReadable(error))
+                        it.setPositiveButton(R.string.ok, null)
+                        it.setNegativeButton(R.string.global_retry) { _, _ ->
+                            threadListViewModel.handle(ThreadListViewActions.TryAgain)
+                        }
+                    }
+                }
+                .show()
     }
 
     override fun onDestroyView() {
         views.threadListRecyclerView.cleanup()
         threadListController.listener = null
+        legacyThreadListController.listener = null
         super.onDestroyView()
     }