Greptile Summary

This PR is a cherry-pick of #645 onto release/v0.9.x that addresses four distinct concerns: CI dependency-resolution flakiness, a MockK strict-mock failure, dual-scheduler races in two test classes, and a message-ordering regression caused by sender clock drift.

The core feature — adding a receivedAt (local reception timestamp) column to the messages table and using COALESCE(receivedAt, timestamp) for ordering — is well-architected. The field is propagated consistently through the entire stack: MessageEntity → Message → MessageUi, with correct handling in both MessageCollector and ServicePersistenceManager. The database migration (40 → 41) is minimal and backwards-compatible for pre-existing rows. A user-facing "Sort by sender's time" toggle is also introduced and wired end-to-end through SettingsRepository, SettingsViewModel, and MessagingViewModel.

Key items to note:

• MessagingScreen.kt adds an unused import androidx.compose.ui.res.stringResource that was never used in any of the diff's changes and should be removed.
• DebugViewModelEventDrivenTest.kt uses withTimeout(2000) to guard against a race with Dispatchers.IO. Inside runTest, withTimeout uses the test scheduler's virtual clock, which will not automatically advance while waiting for real-IO work. In practice this will pass when IO is fast, but if the IO path ever hangs the test will hang indefinitely rather than failing after 2 s — a more robust fix would run the IO-dispatching code on the testDispatcher.

Confidence Score: 4/5

• Safe to merge with two minor items to address: an unused import and a fragile test timeout pattern.
• The core clock-drift fix is well-implemented with a proper Room migration, consistent field propagation through all layers, and a user-facing toggle. All three CI flake fixes are correct. Two non-blocking issues remain: an unused stringResource import in MessagingScreen.kt, and withTimeout(2000) in DebugViewModelEventDrivenTest that uses virtual time and won't reliably guard against a hung IO thread.
• app/src/test/java/com/lxmf/messenger/viewmodel/DebugViewModelEventDrivenTest.kt — the withTimeout guard relies on virtual test time and may not behave as expected if the IO path hangs.

Important Files Changed

Sequence Diagram

sequenceDiagram
    participant Peer as Remote Peer
    participant MC as MessageCollector
    participant SPM as ServicePersistenceManager
    participant DB as Room DB (messages)
    participant MVM as MessagingViewModel
    participant UI as MessagingScreen

    Peer->>MC: LXMF message (timestamp = sender clock)
    MC->>MC: now = System.currentTimeMillis()
    MC->>SPM: DataMessage(timestamp=sender_ts, receivedAt=now)
    SPM->>SPM: receivedAt = System.currentTimeMillis()
    SPM->>DB: INSERT MessageEntity(timestamp, receivedAt)
    SPM->>DB: UPDATE Conversation(lastMessageTimestamp = receivedAt)

    MVM->>MVM: combine(peerHash, refreshTrigger, sortMessagesBySentTime)
    alt sortBySent = false (default)
        MVM->>DB: getMessagesForConversationPaged\nORDER BY COALESCE(receivedAt, timestamp) DESC
    else sortBySent = true
        MVM->>DB: getMessagesForConversationPagedBySentTime\nORDER BY timestamp DESC
    end
    DB-->>MVM: PagingData<MessageEntity>
    MVM-->>UI: PagingData<MessageUi>(receivedAt, timestamp)
    UI->>UI: bubble: formatTimestamp(receivedAt ?: timestamp)
    UI->>UI: detail: "Received" card → receivedAt\n"Sent by Sender" card → timestamp

_{Last reviewed commit: 9f17a5f}