Realm notification on RLMArray not letting me update tables - objective-c

Question

I am currently trying to update my table view when a new chat message is sent. I set a notification block on my collection to notify the table view to begin updating but I keep getting an error saying there were 0 insertions:
Terminating app due to uncaught exception 'NSInternalInconsistencyException',
reason: 'Invalid update: invalid number of rows in section 0.
The number of rows contained in an existing section after the update (8)
must be equal to the number of rows contained in that section before the update (7),
plus or minus the number of rows inserted or deleted from that section (0 inserted, 0 deleted)
and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out).'
Here is my notification code:
- (void)setUpRealmNotifications {
// Observe RLMResults Notifications
__weak typeof(self) weakSelf = self;
self.notificationToken = [[TERMessage objectsWhere:#"conversationID == %#", self.model.serverID] addNotificationBlock:^(RLMResults<TERMessage *> *results, RLMCollectionChange *change, NSError *error) {
if (error) {
NSLog(#"Failed to open Realm on background worker: %#", error);
return;
}
UITableView *tableView = weakSelf.tableView;
// Initial run of the query will pass nil for the change information
if (!change) {
[tableView reloadData];
return;
}
// Query results have changed, so apply them to the UITableView
[tableView beginUpdates];
[tableView deleteRowsAtIndexPaths:[change deletionsInSection:0]
withRowAnimation:UITableViewRowAnimationAutomatic];
[tableView insertRowsAtIndexPaths:[change insertionsInSection:0]
withRowAnimation:UITableViewRowAnimationAutomatic];
[tableView reloadRowsAtIndexPaths:[change modificationsInSection:0]
withRowAnimation:UITableViewRowAnimationAutomatic];
[tableView endUpdates];
}];
}

Answer 1

From the looks of it, the change notification is coming down and updating the UITableView correctly, but it would seem that your UITableView data source isn't matching the same changes.
To ensure both the results of the change notification and the UITableView data source method in charge of managing the cells doesn't fall out of sync, I'd recommend keeping a single RLMResults instance around that both the change notification and table data source refer to.
#property (nonatomic, strong) RLMResults *items;
#property (nonatomic, strong) RLMNotificationToken *token;
// ---
self.items = [TERMessage objectsWhere:#"conversationID == %#", self.model.serverID];
self.token = [self.items addNotificationBlock:^...];
// ---
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return self.items.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
TERMessage *message = self.items[indexPath.row];
UITableViewCell *cell = ...; //configure cell
return cell;
}