From 5f3c9d4d86957d354e16f36f0b63bdac74374129 Mon Sep 17 00:00:00 2001
From: manuroe <manu@matrix.org>
Date: Wed, 4 Jul 2018 09:42:00 +0200
Subject: [PATCH] RoomVC: Fix duplication of read receipts

Regression due to read receipt perf improvement.

Disable the optimisation with `foundSenders` because the assumption "As there is one (the last) read receipt displayed per user" was wrong  for internal processing data.
---
 CHANGES.rst                      |  8 ++++++++
 Riot/Model/Room/RoomDataSource.m | 25 ++++---------------------
 2 files changed, 12 insertions(+), 21 deletions(-)

diff --git a/CHANGES.rst b/CHANGES.rst
index 8cdeb7417..4985c84b2 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,11 @@
+Changes in 0.6.19 (2018-07-04)
+===============================================
+
+Improvements:
+
+Bug fix:
+* RoomVC: Fix duplicated read receipts (regression due to read receipts performance improvement).
+
 Changes in 0.6.18 (2018-07-03)
 ===============================================
 
diff --git a/Riot/Model/Room/RoomDataSource.m b/Riot/Model/Room/RoomDataSource.m
index 436405d0d..2586ed0c2 100644
--- a/Riot/Model/Room/RoomDataSource.m
+++ b/Riot/Model/Room/RoomDataSource.m
@@ -103,26 +103,23 @@
         // new read receipt.
         // To implement it, we need to find the sender id of each new read receipt
         // among the read receipts array of all events in all bubbles.
-        NSMutableArray *readReceiptSenders = [receiptEvent.readReceiptSenders mutableCopy];
+        NSArray *readReceiptSenders = receiptEvent.readReceiptSenders;
 
         @synchronized(bubbles)
         {
-            NSMutableDictionary<NSString* /* eventId */, NSArray<MXReceiptData*> *> *updatedCellDataReadReceipts = [NSMutableDictionary dictionary];
             for (RoomBubbleCellData *cellData in bubbles)
             {
+                NSMutableDictionary<NSString* /* eventId */, NSArray<MXReceiptData*> *> *updatedCellDataReadReceipts = [NSMutableDictionary dictionary];
+
                 for (NSString *eventId in cellData.readReceipts)
                 {
                     for (MXReceiptData *receiptData in cellData.readReceipts[eventId])
                     {
-                        NSMutableArray *foundSenders = [NSMutableArray array];
                         for (NSString *senderId in readReceiptSenders)
                         {
                             if ([receiptData.userId isEqualToString:senderId])
                             {
-                                // We find an existing displayed receipt, remove it
-                                [foundSenders addObject:senderId];
-
-                                if (!updatedCellDataReadReceipts[eventId])
+                                 if (!updatedCellDataReadReceipts[eventId])
                                 {
                                     updatedCellDataReadReceipts[eventId] = cellData.readReceipts[eventId];
                                 }
@@ -133,14 +130,6 @@
                             }
                         }
 
-                        // As there is one (the last) read receipt displayed per user,
-                        // we do not need to search for other read receipts of found users.
-                        [readReceiptSenders removeObjectsInArray:foundSenders];
-                        if (!readReceiptSenders.count)
-                        {
-                            // All senders have been found
-                            break;
-                        }
                     }
                 }
 
@@ -156,12 +145,6 @@
                         cellData.readReceipts[eventId] = nil;
                     }
                 }
-
-                if (!readReceiptSenders.count)
-                {
-                    // All senders have been found
-                    break;
-                }
             }
         }