Feat/commit loss epoch gap backfill

[jgmontoya]

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Summary by CodeRabbit

• New Features

  • Added automatic epoch-gap detection and backfill recovery when undecryptable messages indicate stalled progress.
  • Backfill now runs during initial and ongoing synchronization, including when a pending epoch-stall is detected.
  • Recovery supports previously skipped messages below the synchronization floor once armed, with built-in safeguards to avoid repeated replays.

• Bug Fixes

  • Fixed stored events arriving during subscription activation being incorrectly dropped instead of delivered.
  • Improved error reporting when epoch-gap backfill fails.

• Tests

  • Added/extended integration and regression coverage for replay routing, stalled-epoch backfill, and below-floor recovery behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 62f94419-30da-4f94-916d-3ba98920087f

📥 Commits

Reviewing files that changed from the base of the PR and between 90da57c and 865d5b2.

📒 Files selected for processing (2)

• crates/marmot-app/src/client/sync.rs
• crates/marmot-app/tests/next_event_backfill.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• crates/marmot-app/src/client/sync.rs

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Walkthrough

Epoch-gap backfill detection tracks undecryptable messages by group and epoch, triggers full-history transport reactivation, and suppresses repeated signals after replay. Runtime integration drains pending backfills, while activation ordering ensures stored replay events are routed and tested.

Changes

Epoch-gap backfill

Layer / File(s)	Summary
Stall detection state crates/marmot-app/src/client/epoch_stall.rs, crates/marmot-app/src/client/mod.rs, crates/marmot-app/src/lib.rs	Adds per-group epoch-stall tracking, threshold detection, replay suppression, client state, and initialization.
Ingest-triggered backfill flow crates/marmot-app/src/client/sync.rs, crates/marmot-app/src/runtime/account_worker.rs, crates/marmot-app/tests/since_floor.rs	Arms full-history backfill after qualifying stale ingest failures, drains it during runtime processing, and tests recovery and debounce behavior.
Backfill liveness signaling crates/marmot-app/src/client/sync.rs, crates/marmot-app/tests/next_event_backfill.rs	Prevents next_event from skipping an armed backfill and verifies that empty ingest results still return promptly.
Activation replay routing crates/transport-nostr-adapter/src/lib.rs, crates/transport-nostr-adapter/tests/inbound_routing.rs	Activates routing state before subscriptions and verifies stored replay delivery during activation.

Estimated code review effort: 4 (Complex) | ~60 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title matches the main change: adding epoch-gap backfill handling for commit-loss recovery.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/commit-loss-epoch-gap-backfill

---

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[stage-review]

Ready to review this PR? Stage has broken it down into 5 individual chapters for you:

	Title
1	Fix race condition in subscription activation
2	Implement epoch stall detection logic
3	Integrate stall detector into AppClient
4	Wire backfill recovery into sync process
5	Add tests for epoch-gap recovery

_{Chapters generated by Stage for commit 865d5b2 on Jul 16, 2026 5:30pm UTC.}

[coderabbitai]

Actionable comments posted: 3

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/marmot-app/src/client/sync.rs`:
- Around line 339-344: Update next_event around
epoch_stall.observe_undecryptable so arming epoch_backfill_pending causes the
method to return through its empty-result path immediately, allowing
run_pending_epoch_backfill to execute without waiting for another visible event.
Extend the existing sync tests with steady-state coverage alongside the
cold-boot case, verifying a peel-failed delivery arms backfill and reaches the
pending-backfill flow.
- Around line 351-356: Update run_pending_epoch_backfill so it checks
epoch_backfill_pending without clearing it, attempts activate_transport(None),
and only clears the pending intent after activation succeeds; preserve the early
return when no backfill is pending and do not call epoch_stall.mark_replayed
until successful activation.

In `@crates/transport-nostr-adapter/src/lib.rs`:
- Around line 534-550: Update the activation flow around state.activate and
subscribe_all so failures in subscription issuance compensate all
already-applied changes: tear down any partial subscriptions, revert the
account’s local routing state to inactive, and remove the newly recorded
telemetry before propagating the error. Ensure both zero-subscription and
partial-subscription failures leave state consistent and avoid exposing the
committed activation until subscribe_all succeeds.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: f6945f79-e53c-469f-9554-0e92d73e744e

📥 Commits

Reviewing files that changed from the base of the PR and between 363b1fe and 90da57c.

📒 Files selected for processing (8)

• crates/marmot-app/src/client/epoch_stall.rs
• crates/marmot-app/src/client/mod.rs
• crates/marmot-app/src/client/sync.rs
• crates/marmot-app/src/lib.rs
• crates/marmot-app/src/runtime/account_worker.rs
• crates/marmot-app/tests/since_floor.rs
• crates/transport-nostr-adapter/src/lib.rs
• crates/transport-nostr-adapter/tests/inbound_routing.rs