attempt at fixing https://github.com/vector-im/hydrogen-web/issues/245

src/matrix/e2ee/RoomEncryption.js

@@ -80,14 +80,16 @@ export class RoomEncryption {
     }
 
     async writeMemberChanges(memberChanges, txn) {
+        let shouldFlush;
         const memberChangesArray = Array.from(memberChanges.values());
         if (memberChangesArray.some(m => m.hasLeft)) {
             this._megolmEncryption.discardOutboundSession(this._room.id, txn);
         }
         if (memberChangesArray.some(m => m.hasJoined)) {
-            await this._addShareRoomKeyOperationForNewMembers(memberChangesArray, txn);
+            shouldFlush = await this._addShareRoomKeyOperationForNewMembers(memberChangesArray, txn);
         }
         await this._deviceTracker.writeMemberChanges(this._room, memberChanges, txn);
+        return shouldFlush;
     }
 
     // this happens before entries exists, as they are created by the syncwriter
@@ -314,7 +316,9 @@ export class RoomEncryption {
             this._room.id, txn);
         if (roomKeyMessage) {
             this._writeRoomKeyShareOperation(roomKeyMessage, userIds, txn);
+            return true;
         }
+        return false;
     }
 
     _writeRoomKeyShareOperation(roomKeyMessage, userIds, txn) {

src/matrix/room/Room.js

@@ -232,9 +232,11 @@ export class Room extends EventEmitter {
             }
             decryption.applyToEntries(entries);
         }
+        let shouldFlushKeyShares = false;
         // pass member changes to device tracker
         if (roomEncryption && this.isTrackingMembers && memberChanges?.size) {
-            await roomEncryption.writeMemberChanges(memberChanges, txn);
+            shouldFlushKeyShares = await roomEncryption.writeMemberChanges(memberChanges, txn);
+            log.set("shouldFlushKeyShares", shouldFlushKeyShares);
         }
         // also apply (decrypted) timeline entries to the summary changes
         summaryChanges = summaryChanges.applyTimelineEntries(
@@ -263,6 +265,7 @@ export class Room extends EventEmitter {
             removedPendingEvents,
             memberChanges,
             heroChanges,
+            shouldFlushKeyShares,
         };
     }
 
@@ -314,8 +317,8 @@ export class Room extends EventEmitter {
         }
     }
 
-    needsAfterSyncCompleted({memberChanges}) {
-        return this._roomEncryption?.needsToShareKeys(memberChanges);
+    needsAfterSyncCompleted({shouldFlushKeyShares}) {
+        return shouldFlushKeyShares;
     }
 
     /**