Keep local only messages in the list when a reconnect refreshes the channel

[gpunto]

Goal

Messages that exist only on the device vanish from an open message list when the SDK re-watches the channel
on reconnect. Send a few messages offline, restore the connection while staying on the list, and the ones
the server does not know about disappear. Leaving the channel and coming back does not bring them back; they
reappear only once the app is restarted.

Closes AND-1541

Implementation

Carry local only messages across the refresh in ChannelStateLogic.upsertMessages, instead of replacing the
list with the server page alone.

ChannelLogic.watch() always sets shouldRefresh = true, and the sync manager re-watches active channels on
reconnect, so the replace runs on every reconnect with the list open. Unsent, failed and error messages are
never part of a server response, so they were dropped every time. The rows stay in the database, which is why
a restart shows them again.

Opening a channel from the UI does not take this path: ChatClientStateCalls.watchChannel sets
shouldRefresh = false, so its upserts are additive. Only the reconnect re-watch replaces the list.

Messages the server does return are excluded from the carry over, so the server copy wins over a local one
that has since been sent.

Testing

Two tests in ChannelStateLogicTest, both failing before the change: a local only message survives a refresh,
and the server copy wins when both hold the same id. Dropping the id filter turns the second one red, so it is
not passing vacuously.

Device validation still to do, on the Compose sample: send messages offline against a channel frozen from the
backend so the re-send is rejected, then reconnect while staying on the list. On a build from this branch's
base the list should collapse and drop them until the channel is reopened; on this branch they should stay
put with their failed state.

Summary by CodeRabbit

• Bug Fixes
  • Local-only messages are no longer used as pagination anchors when loading older or newer messages.
  • Local-only messages are preserved during message refreshes.
  • Server-synced messages now replace stale local-only copies with the same ID.
• Tests
  • Added coverage for pagination with local-only messages and refresh behavior.

[github-actions]

PR checklist ✅

All required conditions are satisfied:

• Title length is OK (or ignored by label).
• At least one pr: label exists.
• Sections ### Goal, ### Implementation, and ### Testing are filled (or ignored for dependabot PRs).

🎉 Great job! This PR is ready for review.

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	5.26 MB	5.32 MB	0.05 MB	🟢
stream-chat-android-offline	5.49 MB	5.54 MB	0.05 MB	🟢
stream-chat-android-ui-components	10.64 MB	10.76 MB	0.11 MB	🟢
stream-chat-android-compose	12.87 MB	13.15 MB	0.28 MB	🟡

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
94.1% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[coderabbitai]

Walkthrough

Local-only messages are excluded from pagination anchors. Message refreshes preserve local-only messages missing from server results and replace stale local copies when the server returns the same message ID. Tests cover both behaviors.

Changes

Local-only message handling

Layer / File(s)	Summary
Pagination anchor selection stream-chat-android-state/src/main/java/.../ChannelLogicImpl.kt, stream-chat-android-state/src/test/java/.../ChannelLogicTest.kt	getLoadMoreBaseMessage selects the first or last non-local-only message. It returns null for empty or all-local-only lists. Tests cover backward, forward, and all-local-only cases.
Refresh message preservation stream-chat-android-state/src/main/java/.../ChannelStateLogic.kt, stream-chat-android-state/src/test/java/.../ChannelStateLogicTest.kt	Message refreshes retain local-only messages absent from server results. Server messages replace local copies with matching IDs. Tests verify both cases.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Suggested reviewers: velikovpetar

Merge Risk: 🔵 Low · up to 186a1

A concurrent refresh can still remove a newly updated local-only message. Make the state merge atomic before merging.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 12 functions across 4 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: preserving local-only messages when a channel refreshes after reconnect.
Description check	✅ Passed	The description provides a clear goal, implementation details, issue reference, test coverage, and pending device-validation steps. The UI and checklist sections are not completed, but they are not ce…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

• Fix all pre-merge checks with AI

✨ Finishing Touches 💡 1

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🧪 Generate unit tests (beta)

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[coderabbitai]

Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

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Inline comments:
In
`@stream-chat-android-state/src/main/java/io/getstream/chat/android/state/plugin/logic/channel/internal/ChannelStateLogic.kt`:
- Line 365: Make the refresh merge in ChannelStateLogic.upsertMessages atomic by
synchronizing localOnlyMessagesMissingFrom with ChannelMutableState.setMessages
and concurrent upsertMessage mutations, using the shared lock or a single atomic
state update so no concurrent local-only message is lost.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Advanced

Run ID: 28cf762e-e9f1-4208-88e5-0509a31b6a66

📥 Commits

Reviewing files that changed from the base of the PR and between 155380d and 186a181.

📒 Files selected for processing (4)

• stream-chat-android-state/src/main/java/io/getstream/chat/android/state/plugin/logic/channel/internal/ChannelLogicImpl.kt
• stream-chat-android-state/src/main/java/io/getstream/chat/android/state/plugin/logic/channel/internal/ChannelStateLogic.kt
• stream-chat-android-state/src/test/java/io/getstream/chat/android/state/plugin/logic/channel/internal/ChannelLogicTest.kt
• stream-chat-android-state/src/test/java/io/getstream/chat/android/state/plugin/logic/channel/internal/ChannelStateLogicTest.kt

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[aleksandar-apostolov]

LGTM

[stream-public-bot]

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