fix: self-heal blank screen after tab switch / iCloud sync

[devin-ai-integration]

Summary

Implements the fixes from the investigation in #88 to cure the blank-screen / stale-orb bug after tab-switch + iCloud sync.

Root cause recap: MessagingVC never observed .conversationStoreDidChange, so when pass-2 hydration (or iCloud surgicalRefresh) delivered messages after the UI had already loaded an empty stub, the screen stayed blank. Separately, the loadLastConversation → loadMessagesFromConversation path bypassed MainVC.loadConversation, so refreshAvatarVisibility() never ran — hero orb stayed visible even with messages present.

Changes

Fix A — MessagingVC self-heals on store changes:

// viewDidLoad observer registration:
NotificationCenter.default.addObserver(self,
    selector: #selector(handleConversationStoreDidChange),
    name: .conversationStoreDidChange, ...)

@objc func handleConversationStoreDidChange() {
    guard let current = currentConversationEntity else { return }
    if ai_state != .None || !streamingPartial.isEmpty { return } // don't clobber in-flight turn
    let fresh = conversationManager.getMessages(for: current)
    guard fresh.count > messages.count - 1 else { return }       // only reload if store has more
    loadMessagesFromConversation(...)
}

Fix D — messagesDidReload() hook:

// MessagingVC (base): called at end of loadMessagesFromConversation
func messagesDidReload() {}

// MainVC (override):
override func messagesDidReload() { refreshAvatarVisibility() }

Quick wins in ConversationFileStore:

• prioritizeHydration(id:) — moves the active conversation to the front of the pass-2 hydration queue. Called from loadLastConversation.
• isHydrated(id:) / requestHydrationIfNeeded(id:) — public queries used by the defensive guard in loadMessagesFromConversation: if the store returns 0 messages for a not-yet-hydrated conversation, defer render instead of clearing the screen.
• Eviction tolerance in surgicalRefresh: a pendingEvictions: Set<String> stages missing IDs on the first pass; actual eviction only happens if the file is still missing on the next refresh — prevents transient iCloud download/rename from evicting the active conversation."

Link to Devin session: https://app.devin.ai/sessions/764ee807e9284b4998911008069229b9

[devin-ai-integration]

Original prompt from API User

Investigate a state/render bug in Loop (repo: theashbhat/LoopHarness).

Symptoms reported by Ash:

• While in a conversation, switching to another tab and then returning seems to trigger an iCloud sync on re-entry.
• After returning, the chat sometimes renders as a blank screen — as if it's a new chat — even though the user is (likely) still on the same conversation underneath.
• Sometimes the agent orb is shown even though the conversation already has messages.
• Feels like a state/render desync between the conversation store and the view after sync.

Goal of this session: investigate, do not ship a fix yet.

Please:

1. Locate the code paths involved in:
   • Tab switching / tab focus regain
   • iCloud sync trigger + completion (CloudKit / NSUbiquitous… / whatever Loop uses)
   • Conversation message list rendering
   • Orb visibility logic (when the agent orb appears vs the populated chat view)
2. Identify whether tab re-entry clears or replaces the in-memory messages before re-hydrating from iCloud (a likely race).
3. Identify what signal drives orb-vs-messages visibility, and whether it can be wrongly true post-sync (e.g. keyed off "no messages currently loaded" rather than "conversation truly empty").
4. Write up findings as a markdown report in the repo under docs/investigations/tab-switch-icloud-sync-bug.md including:
   • Suspected root cause(s)
   • Specific files / functions / state flows involved
   • Proposed fix direction(s) (don't implement yet)
   • Any quick wins or guardrails worth adding
5. Open a PR with that report. Add ashbhat as a reviewer.

Keep the PR investigation-only — no behavior changes in this PR. A follow-up PR can implement the fix once Ash reviews the findings.

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
loop-harness	Ready	Preview, Comment	Jun 11, 2026 6:01pm