Unread messages divider did not appear in the message list when marking unread

[laevandus]

🔗 Issue Links

Resolves: PBE-5549

🎯 Goal

Fix an issue where unread messages divider did not appear on mark as unread

📝 Summary

• Invalid unread message id was returned because of incorrect get message before implementation

🛠 Implementation

We need to find a previous message from the message we are marking as unread. API requires the last read message, not the first unread message id. The sorting logic and limiting the fetch to 1 ended up returning the oldest loaded message instead (filter matches, let's say 25 messages before limiting to 1, but we picked the id from the wrong end of results). Due to that reason, MessageListVC tried to reload cell for an older message instead (reloading is needed for making the cell to show the unread messages divider).

🎨 Showcase

Before	After

🧪 Manual Testing Notes

1. Open a channel
2. Mark the last message as unread
   Result: Unread message divider appears.

☑️ Contributor Checklist

• I have signed the Stream CLA (required)
• This change should be manually QAed
• Changelog is updated with client-facing changes
• Changelog is updated with new localization keys
• New code is covered by unit tests
• Comparison screenshots added for visual changes
• Affected documentation updated (docusaurus, tutorial, CMS)

[Stream-SDK-Bot]

SDK Size

title	develop	branch	diff	status
StreamChat	6.9 MB	6.9 MB	0 KB	🟢
StreamChatUI	4.95 MB	4.95 MB	0 KB	🟢

[Stream-SDK-Bot]

SDK Performance

target	metric	benchmark	branch	performance	status
MessageList	Hitches total duration	10 ms	0.0 ms	100.0% 🔼	🟢
	Duration	2.6 s	2.55 s	1.92% 🔼	🟢
	Hitch time ratio	4 ms per s	0.0 ms per s	100.0% 🔼	🟢
	Frame rate	75 fps	78.65 fps	4.87% 🔼	🟢
	Number of hitches	1	0.0	100.0% 🔼	🟢
ChannelList	Hitches total duration	12.5 ms	10.85 ms	13.2% 🔼	🟢
	Duration	2.6 s	2.55 s	1.92% 🔼	🟢
	Hitch time ratio	5 ms per s	4.26 ms per s	14.8% 🔼	🟢
	Frame rate	72 fps	74.72 fps	3.78% 🔼	🟢
	Number of hitches	1.2	0.8	33.33% 🔼	🟢

[github-actions]

	1 Warning
⚠️	The changes should be manually QAed before the Pull Request will be merged

Generated by 🚫 Danger

[Stream-SDK-Bot]

SDK Size

title	develop	branch	diff	status
StreamChat	6.9 MB	6.9 MB	0 KB	🟢
StreamChatUI	4.95 MB	4.95 MB	0 KB	🟢

[sonarqubecloud]

Quality Gate passed

Issues
161 New issues
0 Accepted issues

Measures
0 Security Hotspots
84.2% Coverage on New Code
0.1% Duplication on New Code

See analysis details on SonarCloud