Fix accessing messages with invalid index

[laevandus]

🔗 Issue Link

Resolves IOS-22

🎯 Goal

Fix a rare crash when accessing messages in the ChatChannelViewModel

🛠 Implementation

Not fully sure exact steps, but the crash was triggered when the list changes array contains .update with index pointing at invalid index. This shouldAnimate checks currently displayed messages through the self.messages, not the incoming messages array, then the index is not guaranteed to be safe. One theory is that new message was inserted and at the same time .update was also reported with the list change (e.g. [.insert, .update]).

Thread 0 name:
Thread 0 Crashed:
0   MyApp                       	0x0000000101682ca8 Swift runtime failure: Index out of range + 0 (<compiler-generated>:0)
1   MyApp                       	0x0000000101682ca8 specialized Array._checkSubscript(_:wasNativeTypeChecked:) + 4 (<compiler-generated>:0)
2   MyApp                       	0x0000000101682ca8 specialized Array.subscript.getter + 4 (<compiler-generated>:0)
3   MyApp                       	0x0000000101682ca8 specialized LazyCachedMapCollection.subscript.getter + 4 (ChatChannelViewModel.swift:0)
4   MyApp                       	0x0000000101682ca8 ChatChannelViewModel.shouldAnimate(changes:) + 3060
5   MyApp                       	0x000000010167e38c ChatChannelViewModel.dataSource(channelDataSource:didUpdateMessages:changes:) + 376 (ChatChannelViewModel.swift:422)

🧪 Testing

N/A

☑️ Checklist

• I have signed the Stream CLA (required)
• Changelog is updated with client-facing changes
• New code is covered by unit tests
• Affected documentation updated (docusaurus, tutorial, CMS (task created)

[Stream-SDK-Bot]

SDK Size

title	develop	branch	diff	status
StreamChatSwiftUI	8.01 MB	8.01 MB	0 KB	🟢

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
93.8% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[nuno-vieira]

LGTM! ✅