Add/Fix local echo to threads timeline

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/relation/DefaultRelationService.kt

@@ -168,24 +168,30 @@ internal class DefaultRelationService @AssistedInject constructor(
             msgType: String,
             autoMarkdown: Boolean,
             formattedText: String?,
-            eventReplied: TimelineEvent?): Cancelable {
-        val event = eventReplied?.let {
+            eventReplied: TimelineEvent?): Cancelable? {
+
+        val event = if (eventReplied != null) {
             eventFactory.createReplyTextEvent(
                     roomId = roomId,
                     eventReplied = eventReplied,
                     replyText = replyInThreadText,
                     autoMarkdown = autoMarkdown,
                     rootThreadEventId = rootThreadEventId)
-        } ?: eventFactory.createThreadTextEvent(
+                    ?.also {
+                        saveLocalEcho(it)
+                    } ?: return null
+        } else {
+            eventFactory.createThreadTextEvent(
                     rootThreadEventId = rootThreadEventId,
                     roomId = roomId,
                     text = replyInThreadText.toString(),
                     msgType = msgType,
                     autoMarkdown = autoMarkdown,
                     formattedText = formattedText)
-//                .also {
-//                    saveLocalEcho(it)
-//                }
+                    .also {
+                        saveLocalEcho(it)
+                    }
+        }
         return  eventSenderProcessor.postEvent(event, cryptoSessionInfoProvider.isRoomEncrypted(roomId))
     }
 

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/room/timeline/DefaultTimeline.kt

@@ -448,7 +448,11 @@ internal class DefaultTimeline(
      */
     private fun handleUpdates(results: RealmResults<TimelineEventEntity>, changeSet: OrderedCollectionChangeSet) {
         // If changeSet has deletion we are having a gap, so we clear everything
-        if (changeSet.deletionRanges.isNotEmpty()) {
+        // I observed there is a problem with this implementation in the threads timeline upon receiving
+        // a local echo, after adding && !isFromThreadTimeline below fixed the issue.
+        // Maybe there is a deeper problem here even on the main timeline
+
+        if (changeSet.deletionRanges.isNotEmpty() && !isFromThreadTimeline) {
             clearAllValues()
         }
         var postSnapshot = false